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U n ive rsity Microfilms
300 N o r th Z e e b R o a d
Arm A rb o r, M ic h ig a n 48106
A X e ro x E d u c a tio n Com pany

I
I
73-5446
MILLER, Michael Charles, 1942THE CARBON CYCLE IN THE HP ILIMN ION OF TWO
MICHIGAN LAKES.
Michigan State University, Ph.D., 1972
Botany

U n iv e rs ity M ic ro film s , A XEROX C o m p an y , A n n A rb o r, M ic h ig a n

T H E C A R B O N C Y C L E IN T H E E P I L I M N I O N
OF T W O MICHIGAN

LAKES

By
M i c h a e l C. M i l l e r

A THESIS

Submitted to
M i c h i g a n State U n i v e r s i t y
in partial fulfillment of the r e quirements
for the d e g r e e of
D O C T O R OF P H I L O S O P H Y
Department of

Botany and
1972

Plant

Pathology

PLEASE

Some

NOTE:

pages

may

in d ist i n e t
Filmed

University

as

Microfilms,

have

print.
received.

A

Xerox

Education

Company

ABSTRACT
T H E C A R B O N C Y C L E IN T H E E P I L I M N I O N
OF T W O M I C H I G A N L A K E S
By
Michael

The planktonic
were examined

C. M i l l e r

communities of

to q u a n t i f y

extracellular

sedimentation,

dissolved,
organic

secretion,

acetate

depletion were determined
measurements

c ar b o n .

particulate

of

and

in r e l a t i o n

to

s t a n d i n g c r o p s of a l g a l
particulate organic

carbon

heterotrophic

and g l y c o l a t e ,

an d o x y g e n
simultaneous

carbon,

total

c a r b o n and humic

carbon.
Benthic metabolism affected

trophs more

in t h e

heterotrophic

shallower

u p t a k e of

directly with planktonic
In c o m p a r i n g
organic

R a t e s of p r i m a r y

input of humic material,

u p t a k e of g l u c o s e ,

lake

budgets and dynamics of d i s ­

s o l v e d an d p a r t i c u l a t e o r g a n i c
production,

two contrasting

the

carbon

lake.

In g e n e r a l ,

small organic
algal

two la k es ,

the

hetero—

th e

molecules varied

p r o d u c t i o n and

secretion.

si z e o f t h e p a r t i c u l a t e

po ol w a s p r o p o r t i o n a l

primary production.

the planktonic

to the r a t e s of

T h e s i z e of t h e d i s s o l v e d o r g a n i c

M i c h a e l C.
carbon pool was apparently related
a m o u n t s of
lakes the

limiting nutrients.

a l g a l c e ll

ranked

rupture,

by

a nd p a r t i c u l a t e o r g a n i c
Rates of

in r a i n w a t e r ,

plants,

these

and

secretion by and

phytoplankton

and organic

integrating

i n to t h e

autolysis

carbon decomposition

transfer

discussed and a model
s en t e d .

In t h e d e e p e r o f t h e t w o

importance were:

runoff

d e c o m p o s i t i o n of a q u a t i c

co lumn.

inversely to the

inputs of d i s s o l v e d organic c a r b o n

surtace wate r s

Miller

secretion,

in t h e w a t e r

carbon pools
results

a re

is p r e ­

AC K N O W L E D G M E N T S

The author would
a p p r e c i a t i o n to Dr.
logical

l i k e to e x p r e s s

Robert

G. W e t z e l ,

Station and the D e p a r t m e n t of

Pathology,
patience,

Michigan State University
a nd c o n t i n u e d

support of

much valuable criticism during
t i g a t i o n and
ciation
W.

K.

Kellogg
fo r

K.

sincere
Kellogg

for his a d v i c e ,

this work and

t h e c o u r s e of

Biological
financial

George

Station,

assistance

Bio­

Botany and Plant

for

the

inves­

in p r e p a r a t i o n of t h i s m a n u s c r i p t .

is a l s o d u e to Dr.

versity,

W.

his

Appre­

H. L a u f f , D i r e c t o r ,
Michigan
an d

State Uni­

institutional

support.
A s p e c i a l v o t e of a p p r e c i a t i o n m u s t g o
David

G.

whose

inspiration and g u i d a n c e

always

Frey,

D e p a r t m e n t of

Indiana University,

in t h o s e e a r l y y e a r s w i l l

be r e m e m b e r e d .
The graduate

logical
exchange

Station

student

f r o m 1967

and testing of

e v o l u t i o n o f t h is
Boraas,

Zoology,

to Dr.

Dr.

to

body

at t h e K e l l o g g

1970 all

hypothesis

approach.

Harold Allen,

Dr.

contributed

w h i c h led

to

Appreciation goes
Peter

Bio­

Rich,

Dr.

in the

the
to M a r t i n

Robert

Keen,

Dr.
My

J oh n O'Brian,
special

r e v i e w of

thanks

Robert

to D r . R o b e r t

and Dr.

Keen

for

Bruce Manny.

his critical

th i s m a n u s c r i p t .

These
the Federal

investigations were

Water

by the U.S.

Atomic

1 5 9 9 ( C o o - 1 599-24)
Grant GB-6538

supported,

in p a r t ,

by

Pollution Control Administration,

Research Fellowship

5 —F l - W P — 37,

44 9 - 0 1 , - 0 3

Energy Commission,
and

t o R.

by t h e N a t i o n a l

G. W e t z e l .

assisted

by t h e N a t i o n a l

BO-15665

to G.

for

Peterson,

to t h e a u t h o r

C o n t r a c t A T (11— 1) —
Science Foundation

The study was

further

Science Foundation Grant

H. L a u f f , et al^.

Inve s t i g a t i o n of F r e s h w a t e r

(Coherent A r e a s
Ecosystem).

Program

T A B L E OF C O N T E N T S
Page
LIST
LIST
LIST

OF T A B L E S ............................................
vi
OF F I G U R E S ............................................... v i i i
OF A B B R E V I A T I O N S ........................................x i i i

Chapter
I.

INTRODUCTION
A.
B.
C.
D.

II.

IV.

1

C a r b o n C y c l i n g in L a k e s
. . . . .
D i s s o l v e d O r g a n i c C a r b o n ................
Particulate Organic Carbon
. . . .
O b j e c t i v e s ...................................

1
3
9
10

T H E L A K E S .........................................
A.
B.

III.

......................................

L a w r e n c e L a k e ...............................
D u c k L a k e ...................................

12
12
17

M E T H O D S .............................................

21

RESULTS

32

A.
B.
C.
D.
E.
F.
G.
H.

A N D D I S C U S S I O N ...........................

M e a s u r e m e n t and P r e d i c t i o n of P r i m a r y
P r o d u c t i o n and S e c r e t i o n by P h y t o plankton
32
Diur n a l Patterns of P h o t o s y n t h e s i s
a n d S e c r e t i o n ..............................
G1
Annual Budgets of Primary P r o d u c t i o n
and S e c r e t i o n ..............................
G9
Z o o p l a n k t o n E x c r e t i o n ....................
71
A l g a l C e l l C a r b o n and P a r t i c u l a t e
O r g a n i c C a r b o n R e p l a c e m e n t B a s e d on
P lank t o n i c — p h o t o s y n t h e s i s
72
S e d i m e n t a t i o n of P a r t i c u l a t e C a r b o n
.
B7
P l a n k t o n M e t a b o l i s m C o m p a r e d to
W h o l e L a k e R e s p i r a t i o n in W i n t e r
.
.
104
D i s s o l v e d O r g a n i c C a r b o n , Its S o u r c e s
a n d U t i l i z a t i o n ...............................107

iv

Chapter

Page
I.
J.
K.
L.

V.
VI.

P l a n k t o n i c S o u r c e s of D O C ...................
Heterotrophic Uptake of Labile
......................
Organic Compounds
T u r n o v e r o f the S e c r e t o r y P oo l of
Organic Substrates
......................
Planktonic Production and Bacterial
Heterotrophy
..............................

INTERPRETATION AND

131
134
147
156

I N T E G R A T I O N ................... 16 4

C O N C L U S I O N S .............................................171

LITERATURE CITED

..........................................

17 5

APPENDICES
Appendix
A.
B.

P h y s i c a l - C h e m i c a l L i m n o l o g y o f D u c k Lake,
K a l a m a z o o Co., M i c h i g a n
......................

190

M o d e l for C a r b o n - F l o w i n the M i c r o p l a n k t o n
of a L a k e a t l m .

206

v

LIST OF TABLES
Table

Page

1.

M o r p h o m e t r i c p a r a m e t e r s o f L a w r e n c e L a k e and
D u c k L a k e .................................... 14

2.

S u m m a r y of m e a n o b s e r v e d r a t e s of p r i m a r y p r o ­
d u c t i o n a n d s e c r e t i o n in L a w r e n c e a n d D u c k
L a k e s ........................................37

3.

P a r t i a l c o r r e l a t i o n by s e q u e n t i a l a d d i t i o n o f
v a r i a b l e s for p r i m a r y p r o d u c t i o n a n d a l g a l
s e c r e t i o n in L a w r e n c e and D u c k L a k e s . . .

4.

C o r r e l a t i o n b e t w e e n p r o d u c t i o n in L a w r e n c e
L a k e an d D u c k L a k e o n the s a m e d a y or
a d j a c e n t d a y s ............................ 46

5.

D i u r n a l p a t t e r n of p r i m a r y p r o d u c t i o n and
s e c r e t i o n 1 2 — 13 J u n e 1968; L a w r e n c e L a k e
at l m ........................................64

6.

Diurnal primary p r o d u c t i o n and e x t r a c ellular
r e l e a s e 25 A p r i l 1969; D u c k L a k e a t lm
.

7.
8.
9.

10.
11.

39

.

A n n u a l b u d g e t s o f p r i m a r y p r o d u c t i o n and
s e c r e t i o n in L a w r e n c e a n d D u c k L a k e s . . .
E f f e c t of
carbon

67
70

z o o p l a n k t o n g r a z i n g o n r a t e s of a l g a l
fixation and or g a n i c secretion.
.
.

73

C o m p a r i s o n o f m e a n s t a n d i n g c r o p s , r at e s,
an d
r e p l a c e m e n t t i m e s of a l g a l c e l l c a r b o n ,
particulate and dissolved organic carbon
p o o l s in L a w r e n c e a n d D u c k L a k e s
. . . .

85

S e d i m e n t a t i o n budgets, L a w r e n c e Lake, 1 F e b r u ­
a r y 1 9 6 9 - 2 7 J a n u a r y 1 9 7 0 (361 da y s)
.
.
.

92

R e d u c t i o n in d i s s o l v e d oxygen c o n c e n t r a t i o n s
u n d e r t he ice in L a w r e n c e a n d D u c k Lakes.

vi

.

106

Page

Table
12.

H u m i c c a r b o n b u d g e t s for L a w r e n c e a n d D u c k
L a k e s ................................................. 128

13.

C o m p a r i s o n of k i n e t i c b i o a s s a y p a r a m e t e r s in
L a w r e n c e a n d D u c k L a k e s ........................... 135

14.

M u l t i p l e r e g r e s s i o n —p a r t i a l c o r r e l a t i o n
a n a l y s e s o f s u b s t r a t e u t i l i z a t i o n for
g l u c o s e , a c e t a t e , and g l y c o l a t e
. . .

15.
16.

.

C o m p a r i s o n o f a u t o t r o p h y vs. p o t e n t i a l h e t e r o t r o p h y i n t wo l a k e s o n the s a m e d a y s at lm.

140
159

A nnual pe l a g i a l c a r b o n budgets for Lawrence
a n d D u c k L a k e s ...................................... 174

vii

L IS T OF F I G U R E S
Figure
1.

2.

3.
4.

5a.

5b.

6a.
6b.

7a.

Page
Diagra m m a t i c r e p r e s e n t a t i o n of c a r b o n transfer
in t h e p l a n k t o n of a n i d e a l i z e d lake
(------- , p a r t i c u l a t e c a r b o n t r a n s f e r ,
dissolved organic carbontransfers,
*--- *---- *
t r a n s fe r s ) ....................

6

H o r p h o m e t r i c m a p of L a w r e n c e Lake, B a r r y
C o u n t y , M i c h i g a n c o n s t r u c t e d w i t h t h e aid
of s o n a r {200Kc sec"^, M o d e l F — 8 50A,
F u r u n o E l e c t r i c C o . , L t d . ,J a p a n ) . . . .

16

M o r p h o m e t r i c m a p of D u c k L a k e , K a l a m a z o o
County, M i c h i g a n
...............................

19

Isopleths of particulate primary p r o d u c t i o n
(mg C m ~ 3 d a y -3-), L a w r e n c e L a k e f r o m A p r i l ,
1968, to A u g u s t ,
1 9 6 9 .........................

34

P r i m a r y p r o d u c t i o n (mg C m - ^ d a y - -*-) in th e
0 -5 m s t r a t u m (solid line) and a l g a l
secretion or extracellular organic p r o ­
d u c t i o n (mg C m “ 2 d a y - -*-) (dashed line) in
L a w r e n c e L a k e f ro m A p r i l , 1968, to
August,
1969
...................................

36

P r i m a r y p r o d u c t i o n an d a l g a l s e c r e t i o n o r
e x t r a c e l l u l a r r e l e a s e (mg C m -3 d a y -3-) at
lm in L a w r e n c e Lake, f r o m A p r i l , 1968,
to
August,
1 9 69
...................................

36

Isopleths of particulate primary p r o d u c t i o n
(mg m — 3 d a y -3-)in D u c k Lake, 1 9 6 8 — 1 9 6 9
.

.

Isopleths of algal s e c r e t i o n or ext r a c e l l u l a r
p r o d u c t i o n (mg C m -3 d a y -3-) in D u c k Lake,
1 9 6 8 - 1 9 6 9 .........................................
—2

42

—1

P r i m a r y p r o d u c t i o n (mg C m
day
) (solid
line) a n d a l g a l s e c r e t i o n (mg C m - 2 d a y " 3
(dashed line) in D u c k Lake, 1 9 6 8 - 1 9 6 9
.
.

v ii i

42

44

Figure
7b.

8.
9.

10.
11.

12.

13a.

13b.

14a.

14b.

Page
P r i m a r y p r o d u c t i o n (solid line) and a l g a l
s e c r e t i o n or e x t r a c e l l u l a r p r o d u c t i o n
( da s he d line) in m g C m — 3 d a y - 1 a t l m in
D u c k Lake, 1 9 6 8 — 1 9 6 9 ..........................

44

I s o p l e t h s o f a l g a l s e c r e t i o n (mg C m ^ d a y ^)
in L a w r e n c e L a ke , A p r i l , 1 9 6 8 —A u g u s t , 1969.

49

I s o p l e t h s of t he p e r c e n t a g e e x t r a c e l l u l a r
r e l e a s e (PER) in L a w r e n c e L a ke , A p r i l ,
1 9 6 8 —A u g u s t , 1 9 G 9 ..............................

56

I s o p l e t h s of p e r c e n t a g e e x t r a c e l l u l a r r e l e a s e
(PER) in D u c k L ak e , 1 9 6 8 - 1 9 6 9 ................

59

Diur n a l p a t t e r n of p r i m a r y p r o d uction, algal
s e c r e t i o n , p e r c e n t a g e s e c r e t i o n o v e r s hort,
n o n — o v e r l a p p i n g i n c u b a t i o n s a t lm, L a w r e n c e
Lake, 12 June, 1968

63

Diur n a l p a t t e r n ofprimary production, algal
s e c r e t i o n , PER, g l u c o s e h e t e r o t r o p h i c
u p t a k e p o t e n t i a l (Vm a x ) / a n d t h e m a x i m a l
e s t i m a t e of n a t u r a l s u b s t r a t e c o n c e n ­
t r a t i o n o f g l u c o s e (as ug C 1 ~ 3 , D u c k Lake,
lm, 25 A p r i l , 1 9 6 9 ) .........................

66

P a r t i c u l a t e o r g a n i c c a r b o n (— ------- ) (mg C
m “ 2 X 1 0 2 ) a n d a l g a l c e l l c a r b o n (--------)
(mg C ~ 2 X 10l) in L a w r e n c e
Lake, 1 9 6 8 — 69
.

76

P a r t i c u l a t e o r g a n i c c a r b o n (---------) (mg C
m — 3 X 1 0 2 ) and a l g a l c e l l o r g a n i c c a r b o n
(------- ) (mg C m -3 X 101) at lm in
L a w r e n c e Lake, 1 9 6 8 - 1 9 6 9
...............

76

T u r n o v e r or r e p l a c e m e n t
t i m e (days) of a l g a l
c e l l c a r b o n (---------) a n d p a r t i c u l a t e
o r g a n i c c a r b o n (------- ) by p h y t o p l a n k t o n
p r i m a r y p r o d u c t i o n (minus 30% for r e s p i r ­
a t i o n day~l) p e r m 2 of the 0 — 5m s t r a t u m in
L a w r e n c e Lake, 1 9 6 8 — 1 9 6 9
...............

78

Turnover or replacement time
(days) o f a l g a l
cell carbon (
) and particulate
o r g a n i c c a r b o n (------- ) by p r i m a r y p r o ­
d u c t i o n (minus 30% for r e s p i r a t i o n d a y " M
a t lm in L a w r e n c e L ake, 1 9 6 8 — 1969.
.
. .

78

ix

Page

Figure
15.
16a.

16b.

17a.

17b.

18 .

19.

20.

21.

I s o p l e t h s of p a r t i c u l a t e o r g a n i c c a r b o n
(g C m — 3) in D u c k Lake, 1 9 6 8 — 196 9 . .

.

.

Particulate organic carbon (
) (mg C
m — ^ x 10^) a n d a l g a l c e l l c a r b o n (-------- )
{mg C m ~ 2 x 103) in D u c k L ake, 1 9 6 8 — 1 9 6 9

80

.

82

—3
2
Particulate organic (
) (mg C m
X 10 )
a n d a l g a l c e l l c a r b o n (------- ) (mg C m — 3 X
10^) in D u c k L a k e at lm, 1 9 6 8 — 1 9 69
. . .

82

T u r n o v e r or r e p l a c e m e n t t i m e (days) o f a l g a l
cell carbon (
) and particulate
o r g a n i c c a r b o n (-------) b y p r i m a r y p r o ­
d u c t i o n (minus 30% for r e s p i r a t i o n d a y “ l)
p e r m e t e r ^ in D u c k L a k e , 1 9 6 8 - 1 9 6 9
. . .

84

T u r n o v e r or r e p l a c e m e n t t i m e (days) o f a l g a l
cell carbon (
) and part i c u l a t e
o r g a n i c c a r b o n (-------) by p r i m a r y p r o ­
d u c t i o n (minus 30% for r e s p i r a t i o n d a y “ ^ )
p e r m e t e r ^ a t lm in D u c k L a k e , 1 9 6 8 — 19 6 9

.

84

D r y w e i g h t of m a t e r i a l in s e d i m e n t t r a p s d a y ^
at S t a t i o n A and D c o m b i n e d w i t h 90% c o n f i ­
d e n c e i n t e r v a l s w h e r e n = 3 (mg d r y wt.
m - 2 d a y ” 1); fi v e m e t e r t r a p s {------- ) an d
10 or 1 1 m t r a p s (------- ) ........................... 89
_T
O r g a n i c c a r b o n s e d i m e n t a t i o n r a t e s (mg C m
d ay ~ l) at 5m (------- ) a n d 10 or 1 1 m
(-------) in L a w r e n c e La k e, 1 9 6 9 - 1 9 7 0 . . .
91
P e r c e n t a g e o r g a n i c c a r b o n o f the d r y w e i g h t of
p a r t i c u l a t e m a t e r i a l s e d i m e n t e d w i t h 90%
c o n f i d e n c e i n t e r v a l w h e r e n = 3 at 5m
(------- ) a n d io or 1 1 m -(--------) in
L a w r e n c e Lake, 1 9 6 9 — 1 9 7 0 ......................

94

P e r c e n t a g e CaCC > 3 of th e d r y w e i g h t p a r t i c u l a t e
m a t e r i a l s e d i m e n t e d w i t h (9 0% c o n f i d e n c e
i n t e r v a l w h e r e n = 3 at 5 m {------- ) and 10
or 11m (------- ) in L a w r e n c e Lake, 1 9 6 9 —
1 9 7 0 .................................................

96

x

Figure

Page

22.

R a t e s o f t u r n o v e r (days) of p a r t i c u l a t e o r g a n i c
c a r b o n by s e d i m e n t a t i o n in L a w r e n c e Lake,
0 — 5m s t r a t u m (lower) and s t a n d i n g c r o p s o f
p a r t i c u l a t e o r g a n i c c a r b o n (mg C m ~ 2 X 103)
0 — 1 0 m p e r m 2 s u r f a c e a r e a at 0 m [-------)
a n d 0 - 5 m p e r m 2 o f 5m s u r f a c e a r e a (------- )
( u p p e r ) ................................................ 102

23.

I s o p l e t h s of t o t a l d i s s o l v e d o r g a n i c c a r b o n
(mg C l - 3) in L a w r e n c e Lake, 1 9 6 7 - 1 9 7 0 .

24.
25a.

25b.

26.
27.

28.

29.

30.

31.

.

.

109

I s o p l e t h s of t o t a l d i s s o l v e d o r g a n i c c a r b o n
(mg C 1~1) , D u c k Lake, 1 9 6 8 — 1 9 6 9 .................

112

I s o p l e t h s of u l t r a v i o l e t a b s o r p t i o n (250nm,
lcm) b y d i s s o l v e d humic m a t e r i a l s , L a w r e n c e
Lake, 1 9 6 7 - 1 9 7 0

115

I s o p l e t h s of f l u o r e s c e n c e (460nm, lOx s c a l e
unit s) in L a w r e n c e L a k e f r o m J a n u a r y , 1969,
to May, 1970

115

2
H u m i c a c i d o r g a n i c c a r b o n per m e t e r
in
L a w r e n c e L a k e (g C m ~ 2 ) ............................. 117
W e e k l y p r e c i p i t a t i o n at K e l l o g g B i o l o g i c a l
S t a t i o n , K a l a m a z o o C o u n t y , M i c h i g a n and
d e v i a t i o n s o f t h e lake l e v e l f r o m th e a n n u a l
mean, 1967-1970

119

I s o p l e t h s of u l t r a v i o l e t a b s o r p t i o n (250nm,
lcm) by h u m i c m a t e r i a l s (upper) and r e l a t i v e
f l u o r e s c e n c e ( 3 60 n m 1° fi l te r ) in f l u o r o m e t e r
u n i t s X 10 in D u c k Lake, 1 9 6 8 — 196 9 . . . .

122

H u m i c a c i d o r g a n i c c a r b o n p e r m e t e r ^ (g C m~2)
(------- ) , t o t a l d i s s o l v e d o r g a n i c c a r b o n
(g C m~2) (-- ^ — ) and the d i f f e r e n c e b e t w e e n
t h o s e two, r e p r e s e n t i n g t h e m a x i m u m D O C o f
a u t o c h t h o n o u s o r i g i n (-- 0 ---) , D u c k L a k e . .

124

C h a n g e s in u p t a k e v e l o c i t y (Vm a x ) , s u b s t r a t e
c o n c e n t r a t i o n (Kt + S n ) a n d t u r n o v e r t i m e
(Tt) of g l u c o s e , a ce t a t e , a n d g l y c o l a t e in
L a w r e n c e L a k e at lm, 1 9 6 3 — 1 9 6 9

137

C h a n g e s in u p t a k e v e l o c i t y (Vm a x ) , m a x i m u m s u b ­
s t r a t e c o n c e n t r a t i o n (K^- + S n > a n d t u r n o v e r
t i m e (Tt ) o f g l u c o s e , a c e t a t e , and g l y c o l a t e
in D u c k L a k e a t lm, 1968 — 1 9 6 9

139

xi

Page

Figure
32.

33.

34.

35.

36.

14
Heterotrophic Uptake Rateof
C Glucose
C a r b o n (yig C 1 _ 1 h r - 1) at 1 . 7 — 1.8 a n d
0 . 7 5 - 0 . 8 0 y g C l - i f r o m Ma y , 1968, to
A u g u s t , 1 9 69 ......................................

145

Primary production, glucose heterotrophic
u p t a k e CVm a x ) , and i n s o l a t i o n (cal c m “ 2
day~i) d e t e r m i n e d in s h o r t - t e r m s m a l l
bottle incubations usi n g water taken from
t h e l a ke a t lm on t h a t d a y (------- ) and
f ro m a 20 1 c a r b o y p l a c e d in th e l a k e o n
S e p t e m b e r 9, 1969 (---- )
......................

149

T i m e c o u r s e o f the u p t a k e
of secreted organic
c a r b o n f r o m p h y t o p l a n k t o n p h o t o s y n t h e s i s in
c o m p a r i s o n to u p t a k e o f g l u c o s e .................. 152
Isopleths of turnover of algal s e c r e t o r y
o r g a n i c c a r b o n by h e t e r o t r o p h i c u p t a k e of
t h e ^in s i t u b a c t e r i a , D u c k Lake, 1 9 6 8 - 1 9 6 9

.

V e r t i c a l p r o f i l e s of p r i m a r y p r o d u c t i o n , a l j a l
secretions, percentage extracellular
r e l e a s e , a n d t u r n o v e r of a l g a l o r g a n i c
s e c r e t i o n s by h e t e r o t r o p h i c b a c t e r i a l
u pt a k e . D u c k Lak e, 3 J u n e , 1 9 6 9 ...............

155

158

O

37.

38.
39.

40.

41.
42.

T e m p e r a t u r e C C) a n d c o n d u c t i v i t y (ymhos)
i s o p l e t h s in D u c k L a k e f r o m S e p t e m b e r , 1968,
to S e p t e m b e r ,
1969 .............................
Oxygen concentration
(mg 0 2 1
in D u c k L a k e
f r o m S e p t e m b e r , 1968, t o S e p t e m b e r , 1969.

193
. 195

pH a n d a l k a l i n i t y (mg
CaC0 3 1
i s o p l e t h s in
D u c k L a k e , S e p t e m b e r , 1968, t o S e p t e m b e r ,
1 9 6 9 .................................................

197

T o t a l d i s s o l v e d p h o s p h o r u s (yg P 1
in D u c k
Lake, f r o m S e p t e m b e r , 1968, to S e p t e m b e r ,
1 9 6 9 .................................................

199

A l g a l c e l l n u m b e r s (# x 10^ 1 1 ) a n d a l g a l c e l l
v o l u m e (y3 x 10^ l ” i) a t l m in D u c k L ake.
.

202

A l g a l c e l l n u m b e r s (#
x 10^ 1
and algal
v o l u m e (y3 x 10^ 1~1) in D u c k L a k e f r o m
S e p t e m b e r , 1968, to S e p t e m b e r , 1969
.

cell
.

. 204

L I S T OF A B B R E V I A T I O N S

DOC

Total dissolved organic carbon; non-filterable
o r g a n i c m a t e r i a l by g l a s s f i b e r f i l t e r (less
t h a n 0.3 pm) a f t e i M e n z e l a n d V a c c a r o (1964).

EOP

E x t r a c e l l u l a r organic p r o d u c t i o n = EPP or e x t r a ­
cellular primary production, more exactly called
a l g a l s e c r e t i o n or e x c r e t i o n ; t h o s e o r g a n i c s u b ­
strates rele a s e d by algal cells d u r i n g p h o t o s y n t h e ­
sis.

PER

Percentage extracellular

release =

s e c r e t i o n / t i m e x 100
algal primary production/time
P OC

Particulate organic carbon — filterable organic
m a t e r i a l ( g r e a t e r than 0.3 urn) r e t a i n e d o n g l a s s
f i b e r f i l t e r s a f t e r m e t h o d s of S t r i c k l a n d and
P a r s o n s (1965/ 1968).

xiii

I.
A.

INTRODUCTION

Carbon Cycling

in L a k e s

In a c l o s e d a q u a t i c e c o s y s t e m ,
processes of

synthesis

and decomposition determine

s t a n d i n g c r o p of o r g a n i c

c arbon.

of o r g a n i c

(1) d e t r i t a l

(2)

storage

algae,

(3)

zooplankton,
component
(b)

the

is the

(6)

fish.

The

The
(a)

and

(d)

communities

is

terrestrial

communities,

tivities may be
accumulates

little organic
relatively

The

c a rb o n,

synthesis

that

d e p e n d s on

and m a i n t a i n s

in l i m i n e t i c

features

more closely

linked

1

produc­

community

usually

a large biomass

limnetic community
and

a nd

in t e m p e r a t e

The terrestrial

short-lived producers.

therefore,

transfer

although their primary

organic matter

synthesis,

including organic

s m al l c o m p a r e d w i t h

long-lived plants.

size of any

r a t e s of

T h e p o o l of n u t r i e n t s

similar.

(5)

the ra t e o f m i n e r a l i z a t i o n .

a v a i l a b i l i t y of n u t r i e n t s ,
ca r bo n .

carbon,

of p r i m a r y

(c)

of p r i m a r y o r g a n i c

mineralized

particulate material,

instantaneous
rates

the

limnetic components

dissolved organic

si z e o f o t h e r c o m p o n e n t s ,

The rate

be,

(4)

r e s u l t of

between components,

t he

are:

bacteria,

and

the d ynamic

of

accumulates

a small biomass

of

Aquatic

production must

in t i m e

and space with

2
the p r o c e s s e s o f o r g a n i c d e c o m p o s i t i o n a n d m i n e r a l i z a t i o n .
Nutrients
1970).

are re-used

The

continual

in h o u r s o r a f ew d a y s

(P o m e r o y

n e a r e q u a l i t y of r a t e s

of p r o d u c t i o n

and d e c o m p o s i t i o n

is r e f l e c t e d

biomasses.

biomass

Algal

during

the

blooms

in e u t r o p h i c

is

first

planktonic
fixation
1965,

after

zo n e of

Some

and

significantly only

or d u r i n g m i d - s u m m e r

Zill

lakes

carbon dioxide

i n to o r g a n i c

compounds

secreted

1956).

(Fogg

The

1952,

carbon

i n g e s t i o n by z o o p l a n k t o n ,

death or

after

l yt i c p h a g e
Granhall

of

or B d e l l o v i b r i o

carbon

after

1969,

(Padan,
Hirsch

aerobic

to t he b o t t o m of the

l a ke w h e r e

(Hargrave

1970b).

some of

the algal

some of

the

ce ll

(e.g., blue

green

Shilo and K i s l e v

19G7,

unpublished data).
are

carbon

by

zooplankton

carbon

and

The

readily
The

limnetic

settles

it d e c o m p o s e s

The

and bacte r i a l

zooplankton.

(1)

rupture

"natural"

is p a r t i a l l y d e c o m p o s e d

Rich

carbon

heterotrophic bacteria.

Non-mineralized organic

1969,

by

Hellebust

by o s m o t i c

secretion and autolysis

u s e d by a v a r i e t y of

bacteria.

(2)

a t t a c k by o t h e r m i c r o b e s

s o l u b l e p r o d u c t s of

particulate

or

the algal cell

and Hofsten

or

in a l g a e m a y be

as d i s s o l v e d o r p a r t i c u l a t e o r g a n i c

and/or autolysis

and bacterial

e a r l y p r o d u c t s of p h o t o s y n t h e t i c

released or

Tolbert

algal

lakes.

synthesized

algae.

a re

released

accumulates

spring p r o d u c t i o n peak

In the p e l a g i c
HCO-j

in s m a l l

slowly

further
assimilate

f i sh c o n s u m e

3
Algal

and

bacterial

r a t e s of c a r b o n c y c l i n g
because
highly
These

herbivores

in u n d i s t u r b e d

are g e n e r a l l y

eutrophic conditions
rates are prese n t l y

radioisotopic

techniques.
change

pH)

techniques,

too

imprecise

(Beyers

Verduin

tracer

techniques

1959,

(1963),

Overbeck

Storch

(1971),

Wright

(1970)

Se k i

tw o p r o c e s s e s

and

the p a r t i c u l a t e
B.

carbon exists
lesser extent,
these

(1968) , H o b b i e
Saunders

(1968),

to the

the

and N a u w e r c k

1967)

algal p r o d u c t i o n

and

a nd

and b a c t e r i a l

often without relating

s t a n d i n g c r o p of

algae,

bacteria

ca r bon.

Dissolved Organic Carbon
an d

in the o c e a n m o s t

as d i s s o l v e d o r g a n i c c a r b o n
as p a r t i c u l a t e o r g a n i c
exceed

the

of

carbon.

a m o u n t of o r g a n i c

Juday

Saunders

1969).

the o r g a n i c

(DOC)

a n d b a c t e r i a by s e v e r a l - f o l d

1934,

transfers

Saunders

(1966b,

Ohle

unpublished

the p h y t o p l a n k t o n
1926,

as

Isotopic

carbon

(1967)

(1969),

Wetzel

such

1969,

1959) .

and d i s s o l v e d o r g a n i c

lakes

two sources

1970).

oxygen or

and Hall

(1969a a n d

tracer methodology,

the

In all

Manny

Allen

have m e a s u r e d

heterotrophy by

O'Brien

in

and bio l o g i c a l l y

follow precisely

(1970),

it e x c e p t

bottle

V e r d u i n e t a_l.

b y t he a l g a e a n d b a c t e r i a .
data) , G o l d m a n et al^.

lakes,

existing methods,

insensitive

1960,

ca n

of

1969,

(light-dark

a nd O d u m

1956,

incapable

(S aunders

Other

iii s i t u d i u r n a l
are

freshwater

the

studied adequ a t e l y only wit h

the

1958,

interactions must control

and,

to a

Minimally
carbon

in

(Birge a n d

It is d i f f i c u l t

to

4

assess

th e d y n a m i c s of d i s s o l v e d

lakes.

T h e p o o l o f DOC h a s m a n y

molecular

forms,

and

its b i o t i c

organic carbon
s ou r c e s ,
effects

(DOC)

a variety

in

of

a r e m o d i f i e d by

the environment.
Major
(1)

s o u r c e s of d i s s o l v e d o r g a n i c

terrestrial

from planktonic
lysis
and

and aquatic
algae and

or o s m o t i c

(4)

Wetzel

1969)

Shapiro

[Figure

leached

a re

formed during

materials

1].

f r o m the

Christman

Otsuki

rooted

aquatic

The

Watt

and Ghassemi
f o r m in

although

lakes

Ghassemi

(Boyd

1968,

1966,

and

(Birge

Shapiro

humus
and Juday

1957).

Humic

of

from

1965,

simple

rooted aquatic

1964,

Christman

and

1966).

studied

extensively

Forsberg

and Taube

Maksimova and Pimenova
1961,

auto-

1966,

(Otsuki and H a n y a

Christman

Extracellular products
been

C3)

humic materials

come directly

l e a c h i n g of t a n n i n s a n d q u i n o n e s
macrophytes

and Fogg

plant tannins

1966,

they may

secretions

higher a ni m a l s

terrestrial

soil w h e r e

(2)

plants,

decomposition processes

similarly

1968)

1957,

include

a l g a e or h y d r o p h y t e s ,

e x c r e t i o n s of z o o p l a n k t o n a n d

a re

1934,

humic materials,

r u p t u r e of d e a d

( G o l t e r m a n 1964,

carbon

Moore

and Tischer

W a t t and Fogg

1966).

of a l g a l

(Fogg

1952,

1967,

Hellebust

1969,
1965,

Merz,

photosynthesis

1963,

Fogg

1965,

Zehnpfennig

Nalewajko

1966,

have

and Watt
1967,
and Klima

Watt

1966,

5

Figure

1.

D i a g r a m m a t i c r e p r e s e n t a t i o n of c a r b o n t r a n s f e r
in t h e p l a n k t o n of an i d e a l i z e d l a ke (---p a r t i c u l a t e c a r b o n t r a n s f e r # ------ d i s s o l v e d
o r g a n i c c a r b o n t r a n s f e r s , --- *----’---- * CC> 2
transfers).

6

PLANKTON
alg al

&

CARBON

b acten al

CYCLE

resp irat*o n _

........................... "l
alpal p h o t o s y n t h e s i s
Z o o p la n k to n

P a r t i c u l a r O rg a n ic
C a rtx jn

y f
. ,A l g a e
•inoestxTi

e^t ion & deatt t / v

ter i a

particulate
inoestior>,
mate int

;r e h. o
d u to jiy S i S

I!&
'

*

TC-

%

D is s o lv e d

O rg a n ic

C arbon

s e d im e n ta tio n

4
exCrelmn

7
Dissolved organic matter may directly
effect the planktonic
inorganic

ions

community,

( S a u n de r s

DOC m a y

act directly

organic

growth

as

factors

or i n h i b i t o r s o f c e l l
bacteria

1957,
(1)

1963,

Wetzel

carbon-energy
and

algae,

in c e r t a i n r e s t r i c t e d c o n d i t i o n s ,

data).

are r e q u i r e d
Provasoli

1964,

Hartman

species

antibiotics

and J a k o b

1949,

All

aquatic
from very
Some

compete with
unpublished

* folic acid,

thiamine

(Hutner an d

1943,

Provasoli

1958)

(xylose,

longchain

f a t t y acids)

of

a l g a e or b a c t e r i a m a y

fo r o t h e r

Lefevre,

species

(Lefevre,

Jakob and Nisbet

1950,

while

be
Nisbet
1951,

an d

1959).
Organic matter

"peptidizing"
synthesis.
logically
Fe (OH)^

(2)

(3) s t i m u l a t o r s

s om e p h y t o p l a n k t o n

Hutchinson

compounds

s e c r e t e d b y one

s ou r c e s ,

(Saunde rs,

s u c h as b i o t i n ,

for g r o w t h by

other o r g a n i c

specific

substrates

as

1971).

first order kinetic mechanisms.

for o r g a n i c
Vitamins

important

small orga n i c molecules

solutions

indirectly

1968,

g r o w t h and d i v i s i o n .

dilute

bacteria

by

a n d c a n be as

and vitamins,

can concentrate

a nd

c a n a c t i n d i r e c t l y by c h e l a t i n g

micronutrient metals

Humic mater i a l s
available

to algae;

and Fe2(C02)^

and C h r i s t m a n

1968,

bind

are

the

necessary

for p h o t o ­

i r o n and h o l d
inorganic

an d R a s h i d

1968,

it p h y s i o ­

forms of

only slightly soluble

Prakish

or

iron,

(Ghassemi

Shapiro

S o d i u m h u m a t e s c o m b i n e w i t h or d e t o x i f y p e s t i c i d e s

1969) .

(DDT),

8
herbicides
(Wershaw,

(2,4,5,
Burcar

trichlorophenoxyacetic

and Goldberg

Three b r o a d classes
m a y be

recognized owing

of dissolved

technology needed

for t h e i r m e a s u r e m e n t :

compounds

primarily

scarcely decompose

waters,
occur

although

(Fede ro v a n d

Rhyanen

1968,

may oxidize

and

s e p a r a t i o n and
structure.

assimilated

1957).

t an n in s ,

and

of n a t u r a l

utilization
Starkely

can

1969,

Ultraviolet

light

(< 350nm)

in s u r f a c e w a t e r s

(Buck

1968).

ability

th a n b y c h e m i c a l

a r e p h e n o l i c p o l y h y dr ox yine t h o x y

c a r b o x y l ic

1964,

and

and

Black

and Chris t m a n

( Gh a s s e m i

small organic

1963)

and C h r i s t m a n
of b i o l o g i c a l

a c i d s — w h i c h are

f r o m d i l u t e s o l u t i o n by b a c t e r i a .

of t h e s e

dynamically

and

1968) .
availability

small molecular weight c o mpounds- - c a r b o h y d r a t e s ,

rap idly.

compounds

ar e

low;

however,

readily
T he

stable with nearly equal

galactose

Concentrations

rates

(Allen

to be

of p r o d u c t i o n

of c a r b o h y d r a t e s —

and f r u c t o s e — m a y b e d e t e r m i n e d

d i r e c t l y or by b i o a s s a y

concen­

th ey c y c l e

T h e i r c o n c e n t r a t i o n s are c o n s i d e r e d

a nd d e c o m p o s i t i o n .
glucose,

Le w i s

the

resistant

solutions

and bacterial

A t the o t h e r e x t r e m e

a m i n o acids,

very

humic materials

1963,

compounds

of p l a n t o r i g i n

a s e t of

trations

Dlyina

iron binding

They

(2)
are

f un g al

(1)

and

a r e c l a s s i f i e d m o r e by t h e m e t h o d of

( C hr i s t m a n

quinones

microflora

in th e d i l u t e

Shapiro

humic

Humic materials

acids

slow

organic compounds

to t h e i r d i f f e r i n g d e g r e e of

the h e t e r o t r o p h i c

which

and CuSO^

1969).

assimilability by

include

acid)

1968,

Hicks

either

and Carey

1968,

9
Hobbie

and W r i g h t

1965,

and W r i g h t and Hobbie
serine,

g l yc i n e ,

and

and acetate— have

(Allen

Kinson

Fogg

Webb

1969,

1968,

malic

1967).

Some

and Nalewajko

1962,

Ho bbie,

Crawford

Lactic,

ci tric,

oxalic

1970).
isolated

cultures

Scendesmus

(Weinmann

lipids

They

almost unknown

glucose,
uronic

acids

without

1926,

bacteria

and
as

Particulate
several

low

in

l evels

containing

Weinmann

sources.

the b u l k of

Walsh

1965a)

availability
(1970)

and

are

hydrolyzed

contained galactose,

This

in S c e n d e s m u s

if it w e r e

a g r o u p of

polysaccharides

1967,

a r a b i n o s e , xylose,

C.

has

Brehm

and exact b i o l o g i c a l

and glucosamine.

in n a t u r a l w a t e r s

a nd

products

m o b ility are

include peptides,

fraction which

mannose,

cultures

in b i o l o g i c a l

( W al s h 1965b).

a polysaccaride

f o u n d at

compounds w h i c h make up

(Birge a n d J u d a y
composition

ha s b e e n

an d

1970).

refractory

DOC.

an d

th a t a c c u m u l a t e d

in S c e n d e s m u s

Intermediate

total

whose

and

Eagle

from extracellular

sterile

the

acids— glycollate

Fogg,

A monosaccharide

larger more

amino acids — glutamate,

1967,

of phytoplankton.

(3)

1967,

Brehm

acids have b e e n

bacteria

Wetzel

i d e n t i f i e d a n d a re q u i t e m o b i l e

1968,

and W r i g h t

in n a t u r a l w a t e r ,

a l . 1968,

alanine— and organic

been

biologically

Vaccaro et

rhamnose,
fraction

fucosc,

accumulated

cultures with

biologically

or

refractory.

Particulate Organic Carbon
organic

carbon

For example,

suspended

in l ak e w a t e r

organic particles

are

10

blown or washed
algae

i n t o the

lake,

in the w a t e r c olumn,

or

arise from decomposed

resuspended benthic material

a n d d e c o m p o s e d b i t s of a q u a t i c m a c r o p h y t e s
alga e.
algal

Two types

of p a r t i c u l a t e

cell carbon

lumped

this

study.

in t hi s a p p r o a c h ;

in p l a n k t o n i c

algae

the

and secre t i o n

of t hi s

ship b e t w e e n p e l a g i c

carbon,

i m p o r t a n c e of
organic

the

the m e a s u r e d
standing
organic

fluxes

relation­

sedimentation

to e s t i m a t e

(4)

the a n n u a l

to d e t e r m i n e

the

in the t r a n s f e r s of
and heterotrophs;
control

simultaneously;
carbon

algal biomass,

and

the

lake

of d i s s o l v e d o r g a n i c

autotrophs

of o r g a n i c

to d e s c r i b e

a deep marl

to e x a m i n e

(3)

and

(1)

of

and

(5)

autotrophy
(6)

to
and

to r e l a t e

to t h e o b s e r v e d

particulate

and

dissolved

the

types of

carbon.
Though

data

(2)

sources

the r e l a t i o n s h i p

c r o p s of

lakes,

dissolved phase

heterotrophy occurring

POC o r i g i n a t e s

algal p i i m a r y p r o d u c t i o n

humic materials;

carbon between

investigate

lake;

o r g a n i c carb on;

especially

of

primary production

budget of non-planktonic

P O C are

1926).

s t u d y were:

contrasting

and a s h a l l o w s o f t w a t e r

of p a r t i c u l a t e

m o s t of t h e

were

Obj e c t i v e s

annual budgets

in t w o

(i'OC) ,

carbon,

s o u r c e s of

(Birge a n d J u d a y

The objectives
and q u a n t i f y

Many

however,

D.

attached

organic carbon

and total p a r t i c u l a t e

considered during

or

varied,

the

this

objectives were
study

is o n e

broad and

a p p r o a c h to e x a m i n i n g

the

11

i n t e r a c t i o n of p r o d u c t i o n a n d d e c o m p o s i t i o n p r o c e s s e s
a natural ecosystem.
over

the annual

is a p o w e r f u l
carbon

flows

The

comparison of contrasting

c y c l e of n a t u r a l

tool

environmental

in u n d e r s t a n d i n g

complex#

factors

r ea l e c o s y s t e m s .

in

systems

perturbations

controlling

II.
A.
Lawrence Lake
ice b l o c k

lake,

is

of A u g u s t a Cre e k

THE LAKES
Lawrence Lake

(85"

in s o u t h w e s t e r n

a r e a of t h e

southwest
times

sides.

the surface

ate

The

1953).

the

fed,

the ma r s h .

T he

we s t e r n corner,

surface

under

northwest

an d

about

consists of

w h i c h is n o w

10

the
system

largely

are

la k e h a s

and c a l c a r e o u s

immediately by muck
two small,

traverse

fallow

below

60cm.

(Vea tch

partially

spring-

and r e c e i v e d r a i n a g e

fr om

a s i n g l e o u t l e t , at t h e

south­

to A u g u s t a Creek.

Lawrence Lake
of marl

to the

s o i l is g e n e r a l l y a s a n d y l o a m of m o d e r ­

inflows

inlets which

lake,

Michigan.

the K a l a m z o o m o r a i n i c

1915),

are u n d e r l a i n

Major

N ) , a terminal

surrounding watershed,

area of

f e r t i l i t y at t h e

The swamps

27'

Barry County,

la k e o n the east,

(Leverett and Taylor
The

42°

covers an area equal

southern outw a s h ap r o n of

f a r m land.

W,

l o c a t e d at the h e a d w a t e r s of o n e b r a n c h

Adjacent marsh vegetation
surface

21'

is a m a r l

lake w i t h g r e a t e r

the d e e p e s t p o r t i o n of

12

the b a s i n .

th a n

8m

Littoral

13
marl

be n ches,

20 m e t e r s

e s p e c i a l l y on
Marl

t h e north,

dredging during

c h a n g e d the s h o r e

by

11% and v o l u m e

of

the

is

m a x i m u m depth
1.29,

shores

by 10%

4 .9 6

and

(Rich

hectares,

12.6 m, m e a n

stolonifera Michx.
Muhl.

5.9 m,
1,

Michx.,
down

Chara

and Naj as

Lawrence
characteristic
a re a s.

Further,

(12.5 m)

was

selected

used

Figure

flexilis

2).

L . , an d C o r n u s

Scirpus

acutus

Floating

(7 s p p . ),

leaved

a nd

Lake was

Rost.

Wetzel

selected because
lak e

for all

to d e t e r m i n e

de pt h .

found
low

any effects

it r e p r e s e n t s

a

in g l a c i a t e d
to v o l u m e

station

Station

that

extending

1971).

surface

A central

r o u t i n e work.

heterophy H u m

& Sc h midt,

a nd T h u y

it has a r e l a t i v e l y
relative

side.

s u b t e r m i n a l i s T o r r ., a

(Wild)

(Rich,

ar ea

a f o u n d a t i o n of

s p p .) , Myr i o p h y H u m

oligotrophic marl

r a t i o an d a h i g h

was

(several

to seven m e t e r s

surface

are c o m m o n on the n o r t h w e s t e r n

S u b m e r g e d are g r o w t h s of S c i r p u s
perennial,

the

surface area
3
2 9 2 , 0 0 0 m , the

b e nc h e s .

Nuphar variegatum Engelm., Potomogeton
N y m p h a e a o d o r a t a Ait.

the

fructicosa

The e m e r g e n t a q u a t i c

is a d o m i n a n t on the m a r l

has

shore development

is b u i l t o n

Pontentilla

1960

The

the v o l u m e

(Table

shores.

s o m e w h a t on

1970a).

depth 5.01%

tussocks,

to

increased

depth

T he m a r s h v e g e t a t i o n
sp.

f r o m shore,

from 1 9 18

line a n d m o r p h o m e t r y

and r e l a t i v e

Carex

extend

n o r t h e a s t and southeast

the p e r i o d

n o r t h e r n and w e s t e r n

lake

in w i d t h ,

th e

D

A

(11 m)

stream

14

TABLE

1.

M o r p h o m e t r i c parameters of Lawrence Lake and
D u c k Lake.
N o t a t i o n and d e f i n i t i o n s follow
H u t c h i n s o n (1957).
L a w r e n c e Lake

Total drainage
Surface
Volume

area

(ha.)

(m^)

Mean depth

(m)

(m)

(m)

Breadth

(ha.)

50
4 .96
2 9 2 , 0 00

Maximum depth

Length

area

(m)

Duck

Lake
48
12

.6

255,000

12 .6

4 .0

5.9

2 .0

349

407

218

305

Shore development

1.29

Relative

5.01%

1 .0 0 %

0.49

0 . 17

depth

Surface area
voTume

Figure 2

Morphometric map of Lawrence Lake- Barry County, Michigan constructed
with the aid of sonar (200Kc sec“f, Model F-850A, Furuno Electric Co,
Ltd., Japan). Transects at depths of less than 2m were confirmed by
direct measurements (cf. Wetzel, et al. in prep, for further details)

8M•
Z6l6m

LAWRENCE LAKE
BAPRv COJNTY. MICHIGAN

E

VE ’is j

17
i n l e t s m i g h t h av e on s e d i m e n t a t i o n of p a r t i c u l a t e m a t e r i a l
d u r i n g p e r i o d s o f h e a v y rain.

Duck Lake
located

(Figure

l ak e

3).

22'

W,

than
h as

the

a regular

restrict

f ou r t i m e s
no

42°

24*

N)

its
its

la s t g l a c i a l

oval

surface

inlet o r o u t f a l l

table.

and

farm

shore

Its s u r f a c e

Ha.,

volume,

1).

The

a r e a is

2 . 03 m e t e r s
the

Macintosh
variable

12.62
(Table

s u b j e c t of

(1960);
from year

The variation

period during

the w a t e r

to year,
level

the c o u r s e

d i e d by

submerged

1969.

255,000 m

she lf.
3

and mean

i n v e s t i g a t i o n by M a n d o s s i a n

h o we v e r ,

in w a t e r

littoral

shoreline vegetation

unlike

level

of

caused changes

this

(1967-68)

Unlike Lawrence Lake

Lake.

in the s p e c i e s

In the h i g h w a t e r

investigation,

and

and

is q u i t e

t ha t o f L a w r e n c e

(sever a l s p p . ) a n d C e p h a l a n t h u s

just b e c o m e

f o r e s t a n d by

zone or

c o m p o s i t i o n of emergent vegetation.

Salix

is c o v e r e d

symmetrical morphometry

w i t h no c l e a r l y d e v e l o p e d

has b e e n

le v el

land.

D u c k L a k e ha s a r a t h e r

d ep t h,

The

the w a t e r

The water sh ed

p r i m a r i l y by second growth o a k - h i c k o r y

lo w

to an a r e a

(12.6 h a . ) .

streams

an

retreat

b a s i n b o u n d e d by

area

lake

It is a l s o

immediate watershed

f l u c t u a t e s w i t h t he w a t e r

fallow

is a s e e p a g e

Kalamazoo County.

formed during

It has

ridges which

basin

Puck Lake

in n o r t h e a s t e r n

ice b l o c k

less

(85°

B.

a b a n d of

occidentalis

selected

L.

h ad

species had

no Scirpus

or T y p h a

18

Figure

3.

M o r p h o m e t r i c m a p of D uck Lake, K a l a m a z o o Count
Michigan.
The do t t e d line denotes the extent
o f the z o n e o f e m e r g e n t a n d f l o a t i n g - l e a v e d
p l a n t s ( u s u a l l y N y m p h e a o d o r a t a ).
The map was
c o n s t r u c t e d w i t h the aTd of s o n a r , d i r e c t
m e a s u r e m e n t s and aerial photography.

19

D U C K

L A K E

SEC. 5 T IS .R .9 W .
KALAM AZOO

C O U N T Y . M IC H IG A N

DO

FEE T
COMTOURS

N

30 0

300

20
were

found.

occupying

The emergents

the

included:

zone

leaved plants

f r o m t he S a l i x b a n d at 0.5 m t o

advena

two meters

purpurea W a l t . , Brasenia Schreberi

( A i t . ) A i t . , N y m p h a e a o d o r a t a Ait.

depth

in o p e n w a t e r

(4.3 ha.)

C e r a t o p h y l l u m d e m e r s u m L. w a s m o s t

there w e r e

colonizing

the b o t t o m of

Duck

Lake

i m p o r t a n t w ay s :
a r e a to v o l u m e
zo n e

(1)
ratio

Duck Lake
(0.49

th a n L a w r e n c e

are,

several

particulate

Lake

differences

in t h r e e

(2)

its

It is m o r e p r o ­

(0.8 vs

less c a r b o n a t e

4.6 m e q

between
the

surface

and consequently

It h a s m u c h

for a c o m p a r i s o n of

meter

completely.

to 0.17)

(3)

stands

Tucker.

3-4

ha s m u c h g r e a t e r

is m o r e d e v e l o p e d .

alkalinity

form a basis

la ke

at

contrasts with Lawrence Lake

ductive per unit volume.

then,

the

abundant

Gmel.,

Beyond

of M y r i o p h y l l u m s p . , a n d P o t o m o g e t o n a m p l i f o l i u s

littoral

2 m

P o l y g o n o m sp. , P o n t e d e r i a c o r d a t a I*. , U t r i c u l a r i a

c o r n u t a M i c h x . , U.
Nuphar

and floating

the two

1

.

lakes which

annual cycle

an d d i s s o l v e d o r g a n i c c ar b o n .

There

of

III.

METHODS

P h y t o p l a n k t o n p r i m a r y p r o d u c t i o n and
were measured with

the

c a r b o n - 14 t e c h n i q u e

(Steemann

Nielsen

1951,

1952)

using

in s i t u

incubations

bottles

(Strickland

1960,

Goldman

1963,

like W e t z e l

(1966a)

and Wetzel

procedure was
preparation)
NaH

14

was

carbon

in

except that additional
us ed to m e a s u r e

the

an o p a q u e
placed
were

then

to a v o i d

Lake an d

1,

2,

glass-stoppered

kept

19 56).

bottles were

incubated

for

Dark

1964).

et

The

a l . (in

high specific

activity

s e c r e t i o n of o r g a n i c

1,

3,

3 meters

5, 7,

10,

Lake and

sa m pl e r .

Pyrex bottles

at 0,

The

s a m p l e was

(125 ml)

which
sunlight

( Go l d m a n a nd W e t z e l

1,

3 m

a constant

specific activity

suspended

12 m e t e r s

in D u c k L a k e w i t h

b o t t l e s w e r e p r e p a r e d at

injected with

of k n o w n

samples wer e

Wetzel

s ma l l

in a l i g h t - t i g h t b o x o u t of d i r e c t

12 m in L a w r e n c e

14

0,

f r o m 0,

photo-oxidative damage

Edmondson

NaH

sampled

non-metallic Van Dorn

into

in

f il t rate.

Water was
in L a w r e n c e

algal

secretion

1,

1963,
5, a n d

in D u c k L a ke .
a m o u n t of

a n d shaken.

All

sterile
The

from a n o n-shading buoy and

4-7 h o u r s m i d - d a y at the d e p t h s

from which

22
they were collected.
through

0.45u

(HA M i l l i p o r e )

vacuum within

15-30 minutes

Simultaneously,
t h r o u g h GS
sterile

0.22u M illipore

aerated vigorously

dilute
lost

14

C as

NaOH.

14

(20-25 ml)

filters

(ca.

fil ters.

This
HC1

10-15 minutes

exposed

Then

2,

4, or

(We t ze l

the p l a n c h e t s

to HC1
14

fumes

for

and

have been

(coated w i t h a

filters we r e

to r e m o v e t r a c e s

C r e m a i n i n g o r p r e c i p i t a t e d by a l g a l

14

determined

C in l ak e w a t e r a n d

no m e a s u r a b l e d e v i a t i o n
increasing

the v o l u m e

through

remaining

a n d d r i e d at

and the d r i e d

in la k e w a t e r b y p l a t i n g

counts with
in

4.4-3.8,

of

growth

1965a).

compounds

was

effectively

to r e m o v e al l

80)

10 m i n u t e s

Self-absorption was

glucose-

filtered

6 m l of t h e t r e a t e d

the surf a c t a n t Tween

Both

inorganic

was

c ° 2 ' anc^ n e u t r a l i z e d w i t h N a H C O ^

stage.

s o l u t i o n of

180 m m Hg

f r o m lake.

Some volatile organic compounds may

at t h i s

35- 4 5 ° C ,

filtered

than

to p H

f i l t r a t e w e r e p l a t e d on a l u m i n u m p l a n c h e t s
5%

were

less

100 ml)

acidified with

for

at

after removal

the r e m a i n d e r

filtrate was

inorganic

Subsamples

4 ml.

required when

range

increasing

fr o m a l i n e a r

and

14

amounts

in d i s t i l l e d w a t e r .

volume plated

used,

for o r g a n i c

increase

Cof

There
in

for Duck L a k e w a t e r

for L a w r e n c e L a k e w a t e r

A s e l f - a b s o r p t i o n c o r r e c t i o n of

up

1.27 3 w a s

6 m l of L a w r e n c e L a k e w a t e r w a s p l a t e d .

23
C o m p u t a t i o n of particulate
algal

carbon

f i x a t i o n an d

s e c r e t i o n d u r i n g p h o t o s y n t h e s i s w a s b a s e d on

the

relationship:

C a s s i m i l a t e d / b o t t l e x 1 .0 6 _

C assimilated m

available/bottle
where

1.06

1959 ).

14

is the

The

C:

(35.0%)

of k n o w n

was

absolute

total

(1962)

counter with

activity.

alkalinity

which

The

a r e b a s e d on the

reference
total

calculated

f r o m the

dissociation constants

Total

alkalinity,

Standard Methods
thermistor
Ohio)

as

titratable

(1965).

themometer

calibrated with

mometer.

Hydrogen

metrically
The

temperature

+ C 0 2 in w a t e r :
(H+ ) < C 03= )
K2 =
base,

( H C 0 3“ )
was

determined

after

Temperature was measured with

a N.B. S.

Yellow

corrected mercury

a

Sp r in g s,

ther­

ion c o n c e n t r a t i o n w a s m e a s u r e d e l e c t r o N or Expand o m a t i c pH m e t e r ) .

r a t e s of p r i m a r y p r o d u c t i o n
the

available

and pH- d e p e n d e n t

(Yellow S p r i n g s C o r p . ,

( B ec k ma n M o d e l

measured during

the

S a u n d e r s et aJL.

temperature

fco2 total)

a

to s t a n d a r d s

carbon

t a b l e s of

of CaCO^

of

f r o m t h e pH,

(H+ ) < H C 0 3")
K1 =

( So r ok i n

a micromil window

The e fficiency

determined by

f or p h o t o s y n t h e s i s w a s

factor

filters was d e t e r m i n e d w ith

N u c l e a r C h i c a g o C o rp . ).

counter

and

C discrimination

a c t i v i t y of the

gas-flow Geiger-Muller
(D-47,

12

available

and secretion

incubation period was

expanded

to the

24

who l e day by a diur n a l
the p r o p o r t i o n o f
th e

the

factor which
to t a l

incubation period.

daily

is the r e c i p r o c a l of

sunlight received during

Incident solar radiation was

monitored daily w ith a Belfort recording pyrheliometer
located within

5 km of

the

lakes.

The err o r in the diurnal
2
e x p a n s i o n of p r i m a r y p r o d u c t i o n p e r m
of l a k e s u r f a c e
area during a m i d - d a y

incubation

1965,

The percentage

Goldman

1960).

is +1 0 %

(Vollenweider

underwater

t r a n s m i s s i o n w a s m e a s u r e d at e v e r y d e p t h by
photometer

(Fred S c h u e l e r ,

Waltham,

li g ht

an u n d e r w a t e r

Ma s s . ) .

P a r t i c u l a t e o r g a n i c c a r b o n w a s d e t e r m i n e d at
depths

in L a w r e n c e

oxidizing
Angel

filterable

984H,

dichromate
The

Lake

solids on glass

precombusted
at

100°C

and was

This

oxidizes most
le ss

t h an

only

single

with

fiber

stored

for e a c h

5% of t h e m e a n

1965,

in d a r k b o t t l e s

1968).

at room
1968)

standard glucose
and r e p r o d u c i b l y

Methodological

error

r a n g e was

value on quadruplicates;

thus,

f i l t e r s w e r e o x i d i z e d at e a c h c o l l e c t i o n depth.

Phytoplankton
modified Lugol's

samples were

iodine

(Edmondson

preserved with
1959:1200).

plankton were counted with a settling chamber
1958)

(Reeve

(Westenhouse

series with

technique efficiently

compounds.

filters

sulfuric acid potassium

to m i n i m i z e d e c o m p o s i t i o n

calibrated

solutions.

500°C)

in D u c k L a k e by

(Strickland and Parsons

acid dichromate was

temperature

and three depths

9

o n an i n v e r t e d p h a s e

contrast microscope

R o d h e 's

The
( U te rmohl
(Wild,

25
M o d e l M — 40).
5 to

Over

100

10 m m t r a n s e c t s

in 10 m l

the m a x i m u m r a n g e o f
of

the m e a n

were

(Lund,

calculated

individual

the 95%

Kipling

s h ap e o r w e r e

(Nauwerck

1963)*
Lake

(Wetzel,

A ll e n,

Dr.

in

confidence

and Le Cren

Rich

taken

in u^l

l -2 u m o t i l e

^).

here

and M i l l e r ,

converted

S lo a n,

f r o m the

reported

1958) .

and Eppley

+20%

Cell

volumes

and closest

literature
counting

for

and e l s e w h e r e

in p r e p a r a t i o n ) .

(1966)

Algal

by values

and S t r a thman

organic

In D u c k L a k e

in

so t h a t

limits were

to o r g a n i c c a r b o n

(C/V= 10 % w h e r e C is p i c o g r a m s
volume

chambers

Harold Allen did cell

1968,

c el l v o l u m e s w e r e
from Mullin,

settling

counted

f r o m the o u t s i d e m e a s u r e m e n t s

geometric

Lawrence

cells we re

carbon

(1967)

a n d V is c e l l

a large p h a s e — refractory

coccoid bacterium was

counted

in th e

same

preparation.
Dissolved organic carbon was determined by
method of Menzel

and Vaccaro

the s t a n d a r d d e p t h s w e r e

(1964).

Water

immediately

vacuum

through precombusted glass
210 m m

Hg in o r d e r

to r e m o v e

without disrupting

living

potassium persulfate
ampulated
N2

and sealed with

was m e a s u r e d w i t h

2

evolved

at

samples

from

filtered
l e ss

than

particulate material
Samples mixed with

(lowered wit h

p u r g e d of all

an o x y g e n

the CC> 2

the

filters

ce l ls .

at p H

in t r i p l i c a t e ,

30 m i n u t e s ,

fiber

the

torch.

3% H^PO^)

were

i n o r g a n i c CC ^ w i t h

After

autoclaving

for

f r o m the p e r s u l f a t e o x i d a t i o n

a non-dispersive

i n f r a r e d CC > 2

ga s

26
analyzer

(B e ck m a n

215a)

Electronik

19).

The

p u r i t y CC > 2

gas.

Triple

enriched

u s ed

instrument was

10% o f

replicates
l e ^s

in L a w r e n c e

t ha n

a nd C a C O ^

the v a l i d i t y of th e

deviated more

5%.

L a ke t h e

At

called

samples

"Gelbstoff"

room temperature

The

(1949),

i n the
were

spectrophotometer,

(18-23°C)

using m a t c h e d
the r e f e r e n c e ;

t h e pH o f

in mg h u m i c

carbon

five

1 ^ by

absorption on
observed

selective

periods an d

sunlight

the lakes;

the

calibrated

minimal

humic acid

in i n f l o w i n g w a t e r d u r i n g

a nd
high

the m a r s h a d j a c e n t

fraction­
carbon
rainfall
to the

lake

in preparation).
Fluorescent humic materials

were

resin;

photo-oxidation;

in the w a t e r of

at

independent methods;

anion exchange
in

119,

1 c m s i l i c a cells.

The UV a bsorption was

values per

filtered

model

n o t a lt e r e d .

carbon val u e s

lake

quantified

absorption of

samples w a s

(Miller,

depths

in s a m p l e v a l u e s

dissolved

by Kalle

Triple distilled water was

ation;

10%;

at 250 n m w a s m e a s u r e d w i t h a H i t a c h i -

Perkin-Elmer UV-visible

selective

than

several

range

ampuls

t h e mean.

with ultra-violet absorption.
water

calibrated with high

to t e s t

Resistant humic materials
wate r,

(Honeywell

T h e m e a n v a l u e of t r i p l i c a t e

generally

f ro m 3 s t a t i o n s

recorder

distilled water blanks

if n o n e of t h e

variance was

was

a sensitive

samples were prepared

sample preparation.
was

and

studied

for c o m p a r i s o n w i t h

in

filtered

l a ke w a t e r

the U V - a b s o r b i n g

humic

27
materials.
460

R e a d i n g s of

nm were taken wi th a T u rn er

ultraviolet bulb
Fluorescence

at

primary

(460 nm)
Buck

110 F l u o r o m e t e r u s i n g

values were c ompared

filter

were

(1968),

checks with

(365 nm)

selected
who

and

to m a k e

investigated

"humic" materials

in f l u o r o m e t e r u n i t s

365 nm a c t i v a t i o n

w a t e r with o c c a s i o n a l
The

l ak e w a t e r

on

and

1 cm

to t r i p l e

distilled

the s e c o n d a r y

standard.

filter

comparable

t h e role of

t he

l i g h t path.

a fluorescent

this w o r k

at

to

fluorescent

the m e t a b o l i s m of a q u a t i c m i c r o c o s m s

and pond ecosystems.
Oxygen concentrations were
u n m o d i f i e d W i n k l e r method.
a 25°C water bat h
(Model RC 16B,
0 . 0 0 7 0 2 N KC1

Instruments)

(1000 ohms).

to u m h o cm ^ x 10^
Cations

on HNO^

acidified,

absorption

Conductivity was monitored

(Ca

specific
, mg

calibrated with

Resistances were
conductance
, K

, and N a

filtered w a t e r

spectrophotometer

calibrated with

) were determined

samples wi th

(Jarrel Ash,

triple distilled water

persulfate o x i d a t i o n method of

Model

an e m i s s i o n 82700)

ion s t a n d a r d s .

Strickland

the p o t a s s i u m
and Parsons

1968).
Kinetic bioassays

1967)

converted

(Standard M e thods

Total dissolved phosphorus was measured by

(1965,

in

using a c on du ct iv ity-resistance bridge

Industrial

1965 ).

d e t e r m i n e d by the

for b a c t e r i a l

after Wright and Hobbie

u p t a k e of g l u c o s e ,

glycollate characterized bacterial

(1965,

a c e t a t e and

heterotrophy

in the

two

28
lakes.

Lake water plankton

opaque bottles with
of

used

A blank

incubated

of kno w n

fixed with Lugol's

the p a r t i c u l a t e m a t e r i a l
and incub a t e d

Subsamples
0.22 u

filtered

of
(GS,

specific

iodine was

present.

Millipore)

The bottles were

la k e w a t e r ,

f i l t e r e d at
filters,

dried,

always

the substrate

at the d e p t h c o l l e c t e d

50 m l w e r e

in

increasing concentrations

to d e t e r m i n e b a c k g r o u n d a b s o r p t i o n of

shaken

on

sequentially

lm w e r e

radioactive organic substrates

activity.

by

from

for

180-340

m m Hg v a c u u m

rinsed with

fumed with

HC1

2-6 hours.

15 ml of

a n d the

radioactivity measured.
An
t y p e of

S/v vs

the L i n e w e a v e r

Michaelis-Menten
(1965),
land
w as

S plot was made

Hobbie

(1962).
tested

equation

and W r i g h t
The

for

steady

state)

e s t i m a t e of
s h o w e d a 20%
ation was

the d a t a

(1968),

t r a n s f o r m a t i o n of

t i m e of the

and Parsons

least

from

the s l o p e

z er o

squares

the

(P =

95%).

The

(1/Vm a x ) , y i n t e r c e p t
substrate

c o n c e n t r a t i o n at

intercept

( (KT + Sn)

in s i t u

substrate

concentration).

in V m a x

and S t r i c k ­
regression

and x

variation

u s i n g o ne

following Wright and Hobbie

significance

turnover

linear

s l o p e of the

key parameters were
(Sn/v o r

Burke

of

although

or

the m a x i m a l
Replicates

the a n n u a l

vari-

2 orders of magnitude.

Heterotrophic

t u r n o v e r of

released extracellular

primary production products was monitored by
bacterial uptake

of

the s e c r e t i o n p r o d u c t s

following

in the p r i m a r y

29
production samples
removed,
The

from which

with pH and alkalinity

f i l t r a t e f r o m a s s a y of

production,

14

inorganic

C had been

r e t u r n e d to

in

s i t u v al u e s .

in s i t u r a t e s of p r i m a r y

was purged with air

for

10 m i n u t e s

a t pH

4 . 3 - 3 . 8 a n d r e t u r n e d to the o r i g i n a l p H a n d a l k a l i n i t y w i t h
NaHCO^

(less t h a n

2 ml per

At the

same t i m e of day,

filtrate was m i x e d

hours

but

1:1 w i t h

d e p t h o f the o r i g i n a l
incubations

100 m l

2 4 hours

incubation.

used
Any

collected.

An

l o ss of b a c t e r i a l

t r e a t m e n t of the

14

(Lugol's

uptake

activity

water

day.

from the previous

HC1

rinsed with

and assayed

calculated
time

for

(hours)

remove

all of

filtered o n t o

filtrate
was

filtered

the

at

treated

0.22u

lake water,

fo r r a d i o a c t i v i t y .
t he

made

c o r r e c t e d by c o m p a r i n g

C of n o n - d i l u t e d p l a n k t o n

Samples were

to 4.5

iodine),

caused by

1:1 w i t h

f il t e r s ,

1.5

for e a c h e x p e r i m e n t a l bot tle.

the u p t a k e of p l a n k t o n d i l u t e d
sample

uptake

s a m p l e of t r e a t e d

filtrate was

of g l u c o s e -

f r om the

identical mixture,

h a d be e n k i l l e d

as an a d s o r p t i o n b l a n k

uptake

Duplicate
for

0 . IN N a O H .

the treated

lake wat e r plankton

f r o m a s e c o n d a l i q u o t of e a c h
plankton

and

later,

in o p a q u e b o t t l e s w e r e m a d e

at the d e p t h

in w h i c h

fi l tr a te )

(GS,

lm w i t h
control

Millipore)

dried,

fumed w i t h

The turnover

time

e x t r a c e l l u l a r - r e l e a s e p r o d u c t s was

it w o u l d

have t a k e n

the o r g a n i c

c o u l d us e the v a r i e t y of

14
14

the

heterotrophs

C present,

C-organic

the

assuming

substrates

the

to

t h at t h e y
at an

30
equal
more

rate.

The

r a n g e of r e p l i c a t e s w a s

t h a n +50% of

large,

b u t no

t h e mean.

S e d i m e n t a t i o n of p a r t i c u l a t e o r g a n i c m a t e r i a l
the e p i l i m n i o n

in L a w r e n c e L a k e w a s m e a s u r e d

i n t e r v a l s by d u p l i c a t e
and

sediment

traps

10 or 11 m at t w o s t a t i o n s ,

paired
long,

traps wer e

A

5 cm diameter

The

frames were

plexiglas

anchored

minimize wave disturbance.
collected
Aliquots

into

jars.

The

precombusted glass

5 m

2).

cylinders,

60 cm

to

from the traps were

traps were

rinsed and resuspended.

sample were

fiber filters.

The

coated wooden

to a s u b m e r g e d b u o y

Samples

of e a c h w e l l - m i x e d

at

(F i gu r e

s u s p e n d e d o n e m e t e r a p a r t o n an e p o x y

frame.

at m o n t h l y

suspended

an d D

from

filtered on tared

T o t a l d r y w e i g h t of

sediment collected was measured on a Mettler microbalance.
The
by

precipitated CaCO^
th e

a m o u n t of C O ^

f r a c t i o n o n the

released by

inside a nitrogen purged

400

CO2

The apparatus was

acidification

cc chamber.

was q u a n t i f i e d by a Beckman CC^
analyzer.

times w e r e

coated CaCO^
a n d Suess,

employed

determined

(3% H^PO^)

T h e CC>2 r e l e a s e d

nondispersive

i n f r a r e d g as

calibrated empirically with

at k n o w n t e m p e r a t u r e a n d p r e s s u r e .

reaction

filter was

to

(Wetzel a n d A l l e n

Four minute

fr e e e v e n o r g a n i c a l l y
1971,

Chave

1965,

and C h a v e

1970).

P a r t i c u l a t e o r g a n i c c a r b o n on t h e
filters was dete r m i n e d using the
o x i d a t i o n of

acid

treated

potassium dichromate

S t r i c k l a n d and P a r s o n s

(1968).

The amount

31
of C a C O ^

and organic car b o n on each

filter was expanded
2
then per m
of s u r f a c e a r e a at

to the a m o u n t p e r t r a p a n d
t ha t d e p t h

in the

lake.

of c o l l e c t i o n d a y s
organic carbon
collection.
less t h a n

amount

bration
All

a p p r o x i m a t e d the m e a n d a i l y

across

that m 2 surface

of

much

the m e a n ;

it w a s

fi l t e r s .

precipitated was

results

s h o w the 90%

A n a l y s e s of D a t a w e r e
computer

at

multiple

regression-partial

i n d e p e n d e n t of

variables

in the

to

limits where

h a n d l e d o n the

correlation
the

the

the
amount
cali­

l a r g e a m o u n t s of CC>2 .

the U n i v e r s i t y of C i n c i n n a t i .

program adding

usually

in p e r c e n t a g e o r g a n i c

the g r e a t e s t because

confidence

f l u x of

traps was

Variation

curves were curvilinear with

th e n u m b e r

a r e a to t h e d e p t h of

replicate

variation

less b e c a u s e

i n i t i a l l y on the

of C a C O ^

result divi d e d by

Variation between

10%

carbon was

The

IB M

n > 3.
360-65

Stepwise

u s e d the

l i n e a r model.

BioMed

02R

IV.
A .

RESULTS AND

DISCUSSION

M e a s u r e m e n t a n d P r e d i c t i o n of P r i m a r y
P r o d u c t i o n and S e c r e t i o n by
Phytoplankton

New organic matter within

th e w a t e r c o l u m n

is

g e n e r a t e d p r i n c i p a l l y by p r i m a r y p r o d u c t i o n a n d s e c r e t i o n
of d i s s o l v e d

organic comp o u n d s by the phytoplankton.

P a r t i c u l a t e or
Lake ranged

f r o m 1 6 — 381 m g C m

e nd of J u n e ,
mean of

filterable primary production

respectively

128 m g C m

—2

day

of p h o t o s y n t h e s i s w a s
1 96 9
day

(Figure
^

2

day

—1

in J a n u a r y t o t h e

(Figure 4, F i g u r e
.

5 a ) ; with a

The max i m u m observed rate

100 m g C m

—3

5 b ) ; the m e a n a n n u a l

day

—1

on June

value was

25,

37. 4 m g C m

—3

(Table

2) at 1 m e t e r .
T h e a n n u a l p a t t e r n of p r i m a r y
—2
(m
) w a s s i m i l a r in 1 9 6 8 a n d 1969, w i t h a

production
spring

—1

—

in L a w r e n c e

pulse

in A p r i l

and

early M a y and

two summer m a x i m a

between June and August.

Th e m i n i m u m p r o d u c t i o n o c c u r r e d

in J a n u a r y —F e b r u a r y u n d e r

the

duction was

positively

m a t i o n o n all d a t a
(0.768),
carbon

materials

algal

(0.324),

correlated

Algal

(0.625),

with light

total dissolved organic

secretion

(0.363),

oxygen concentration

32

primary p r o ­

(after a log t r a n s f o r ­

to n o r m a l i z e v a r i a n c e )

temperature

(0.405),

ice.

hum i c — like
(0.332),

Figure 4.

Isopleths of particulate primary production (mg C
Lawrence Lake from April, 1968, to August, 1969.

PRIM ARY

PRO DUCTIO N mgC mJday''

XVTOv '

0
t

I

1
4

I

I; n

i

t

J

7

u
it*

f
10

s—

S.

j.

11

II
FEB

MAR

APR

MAY

JUN

JUL

AUG

SEP

OCT

NCN

DEC

JAN

FEB

MAR

APR

MAY

xM

JUL

AUG

35

Figure

5a.

Figure

5b.

—2
—1
P r i m a r y p r o d u c t i o n (mg C m
day
) in t h e
0— 5m s t r a t u m ( s ol i d line) a n d a l g a l s e c r e t i o n
o r e x t r a c e l l u l a r o r g a n i c p r o d u c t i o n (mg C m “ 2
d a y - l) ( dashed li n e) i n L a w r e n c e L a k e f r o m
A p r i l , 1 9 6 8 , to A u g u s t , 1969.

P r i m a r y p r o d u c t i o n a n d a l g a l s e c r e t i o n or
e x t r a c e l l u l a r r e l e a s e (mg C m “ 3 d a y ~ l ) a t
in L a w r e n c e L a k e , f r o m A p r i l , 1 9 6 8 , to
A u g u s t , 1969.

Ira

36

PRIMARY

PRODUCTION

mgC m^day

LAW RENCE

400

16

mg C m ^dsy-1
^ROOUCTION

x

30 0

<=
CL

30 0

100

APR

EXTRACELLULAR

L AKE

MAY

J1JN

JUL

AUG

StP

ocr

NOV

Dfc C

JAN

FEB

MAR

MAY

JUN

L AVVRENCL

AUG

JUl

LAKE

_

If
110

r

100

3ft

90

3A

T
XJ
£

>

00

30

10

T)
a
60 ^
70

XF

O

7 a

1 j!
W
1.ft h

3
O

14

ULj

ftl*

1O *

20

0 ft
I
0 2I

V
APR

"
MAY

JUN

JUL

AUG

fiF P

OCT

NQV

DEC

JAN

FEB

WAR

A fJR

MAY

JUN

.HJl

AUC>

37

T A B L E 2.

Depth
(m)

Summary of m e a n o b s e r v e d rates of p r i m a r y p r o d u c t i o n and
s e cr e t i o n in L a w r e n c e and Duck Lakes.

Mean A n n u a l
Primary
Production
mg C m~"3 d a y - i

Lawrence Lake

(Aug.

Kea n Annual
Secr e t i o n
me C m -3 d a y - 1

1968-Aug.

Mean
Secretion
Rate
^secretion
T. 1° Prod.

Mean
Secretion
Rates
£% s e c r e t ion

(*)

N
<%>

1969)

Om

32.0

1.28

3.99

6.8

lm

37.4

1.36

3.65

5.9

3m

30.5

1.29

4.24

6.3

5m

21.8

1.13

5.17

7.4

7m

11.4

8.88

17.9

1.01

10m

2.8

1.48

55.4

71.9

12m

2.9

0.96

32.9

48.5

128.1

7.29

5.7

23.5

M e a n per
m2

Duck Lake

(Sept.

1968-Sept.

1969)

0m

91.6

4.46

4.87

5.31

lm

72.0

2.93

4.07

6.91

3m
Mean per
m2

28.3

132.5

11.58

10.6

39.9

19.3

8.0

10.5

38
pH

(0.301),

(-0.282)

and

and

negatively correlated with

conductivity

(-0.279)

alkalinity

(P = 0 . 9 5 ^ f 244^'

A stepwise addition of transformed variables
c o r r e l a t i o n —m u l t i p l e

regression analysis

light and t e m p e r a t u r e could

explain

showed

67% of

in p r i m a r y p r o d u c t i o n in L a w r e n c e Lake.
(1968)
of

found

that light and

Eleven non-independent variables

algal

ce l l

with rates
0 .188

(p > 0.90),

related with

G o l d m a n et^ a l .

accounted

(available

primary

for

72%

bu t w e r e

production

72 % of

3).

1968)

produ c t i o n r = 0.282

respectively,

for

(Table

particulate organic carbon.

d i c t i o n of d a i l y
t he

and volumes

of p r i m a r y

th e v a r i a n c e

in L a g o M a g g i o r e .

in p h o t o s y n t h e s i s r a t e s

numbers

that

temperature accounted

t h e v a r i a t i o n of p h o t o s y n t h e s i s

t he v a r i a t i o n

in a p a r t i a l

Log
correlated

(p > 0.95)

and

negatively cor­
The best

pre­

in L a w r e n c e L a k e u s i n g

least c o n f o u n d e d varia b l e s would

be:

log p r i m a r y p r o ­

d u c t i o n = 0 . 3 7 4 log l i g h t t r a n s m i s s i o n d a y ^ + 0 . 5 7 9 log
o
temperature
C - 0 . 4 8 2 log c o n d u c t i v i t y — 0 . 1 3 0 log a l k a ­
linity

as m g C a C O ^

67% of

th e v a r i a t i o n .
Primary

production

s a m e d a y or w i t h i n
Lake
C m

—

ranged
2

basis

day

—1

1 ^ + 1.7 39.

from
, was

These

parameters

explained

in D u c k L a k e d e t e r m i n e d o n

the

two d a y s o f t h e m e a s u r e m e n t o n L a w r e n c e

5— 455 m g C m
not

—2

day

—1

.

The mean,

significantly d i f f e r e n t on an aerial

t h a n t h e p r o d u c t i v i t y of L a w r e n c e L a k e

The maximum observed

132 m g

(Table

r a t e of p h o t o s y n t h e s i s w as

2).

TABL£ 3.

I,

Partial correlation by sequential addition of variables for primary production and algal secretion ir. Lawrence and Duck Lakes.
variables significantly change the slope of the multiple regression prediction of the dependent variable.

Primary Production

A.

Lawrence Lake 1963-69

r2 F

B.

-

Secretion

Light

c .112

c.4a

Temperature

PX

;,64

67.59 Critical F ?5(9236)

DOC

pH

:.~!2

:ri

Conductivity

Oxygen

Alkalinity

o n

:."2

* 5-92

Duck Lake 1968-69
Light

Cell volume

Secretion

Bacteria «

Alkalinity

0.750

0.79

2.315

C.83C

r2 ■ 0.53'
F

- 23.61 Critical F

^

Temperature
C.06

Oxygen
C.B7

Cell *

Conductivity

0.07]

0.37

PX
C.B7

pH

Calcium

0.87

c.07

DX
0.877

- 2.0

Humic materials were not added to this run.
P * .95.

II.

Underlined

The simple correlation with primary production was 0,297(r2 ■ C .09> which was significant

U)
VS

Algal Secretion during photosynthesis

A.

Lawrence Lake 1963

r2 f

B.

Production

Dxyqer.

PX

0.20

0.27

0.29

Cell volume
C.31

pH
0.3 3

DX
0.14

Temperature

Conductivity

0,35

0.37

Cell *
C.30

Alkalinity
C.39

Light Humics
0.40

0.405

. 7.05 Critical r,,5(i;il;5} ■ 1-63

Duck u k e 1963-69

r2

Production

Cell »

PX

pH

Conductivity

DX

Light

Humics

Alkalinity

Dkyqeh

0.40

0.61

0.6B

0.70

0.71

C ,72

C.72

0.12

0.73

0,7 3

F - 3.41 Critical F

, . . . - 1.92
.95(i4,42)

Calcium
0.7 3

Temperature

Bacertia *

Cell volume

0,73

0.71

0.7 37

388 m g C m

—3

day

r a t e at O m w a s
g r e a t as

the

—1

on 3 June,

91.6 m g C m

p r o d u c t i o n at

annual photosynthesis
6a,

and

-3

7b).

1969, w h i l e
day

-1

.

This was

(Table

b l o o m in l a t e M a y and e a r l y

(Figure 7a) .

A l a t e sumir.sr o r

in p r i m a r y p r o d u c t i o n w a s

(0.667),

dissolved organic carbon
ticulate organic carbon

multiple

(-0.541),

cell

Light,

numbers,

numbers,

accounted
The best

bacteria

for

cell

conductivity,

primary p r o d u c t i o n = 0.447
l in i ty

- 2.28

°C + 9 . 6 3 3

(0.343),

transformed data

(0.636),

(0.291)

(— 0 . 5 4 7 ) ,
A

algal

showed

secretion,
oxygen,

con­

stepwise
that

66% of t h e v a r i a t i o n

temperature,

in

bac­
algal

P O C , pH, C a + + , a n d D O C
in p r o d u c t i o n

log light - 2.259
.638

(Table

in D u c k Lake

v a r i a b l e s w o u l d be:

log c o n d u c t i v i t y +

(explains 73% of

secretion

total p a r ­

(— 0 . 3 1 6 ) .

primary production

least confounded

algal

ions

the

significant

humic material

88% o f the v a r i a t i o n

p r e d i c t i o n of

using the

pH

number

volume,

alkalinity,

increase

cell volume

with calcium

temperature explained

production.
t er i al

algal

(0.306),

regression on the

light and

(0.733),

(0.377),

and n e g a t i v e correlations
ductivity

light

showed

4

19 69

in b o t h y e a r s a f t e r

Log t r a n s f o r m e d d a t a

temperature

as

by an

J une,

early autumnal

seen

positive correlations with
(0.688),

times

2, F i g u r e s

p a t t e r n was d o m i n a t e d

intense a l g a l

fal l o v e r t u r n .

2.5

the de p t h of m a x i m u m m e a n

in L a w r e n c e L a k e

The annual

the a n n u a l m e a n

log

log a l k a ­

log t e m p e r a t u r e

the variation

in p r i m a r y

3)

Figure 6a.

Isopleths of particulate primary production (mg ir.
in Duck Lake, 1968-1969.

Figure 6b.

Isopleths of algal secretion or extracellular pro­
duction (mg C m~3 day~l) in Duck Lake, 1968-1969.

PRIMARY

PRODUCTION

DEPTH

(m)

Soo

SEP

OCT

NOV

DEC.

JAN.

FEB.

MAR. APR. MAY

JUN. JUL.

EXTRACELLULAR

0

PRODUCTION

'

(m)

\ \ \

AUG. SEP

DEPTH

2

3
4

SEP

OCT

NOV

DEC

JAN.

FEB.

MAR. APR.

MAY JUN.

JUL.

AUG. SEP.

K)

43

Figure

7a.

Figure

7b.

—2
—1
P r i m a r y p r o d u c t i o n (mg c m
day
) ( solid
line) a n d a l g a l s e c r e t i o n (mg C m ~ 2 d a y ~ l )
( d a s h e d line) in D u c k L a k e , 1 9 6 8 — 1 9 6 9 .

P r i m a r y p r o d u c t i o n (solid line) a n d a l g a l
s e c r e t i o n or e x t r a c e l l u l a r p r o d u c t i o n
( d a s h e d line) i n m g C m — 3 d a y - 1 a t l m in
D u c k L a k e , 1 9 6 8 — 1969.

EXTRACELLULAR

PRODUCTION

mg rrr3day'

rr

DUCK

SEP

OCT

NOV

DEC

JAN

FEB

r

MAR

APR

MAY

JUN

JUL

AUG

SEP

s

EXTRACELLULAR
PR O D U C TIO N
mg C rrr2d a y '1
*0 O uS
o
« (N i 2 ^ O
trt

o

o
•ft

o
o

o

L_Aep

o
o
>-

o
o

o
n

«

uj

Noiionaoad

q

Bui

AuvwiHd

c*

8

o*

^ e p ^ .w

S— 8*■ $

0

6 lu

S

8

S

NOIiOnaOdd

S

$

8

AHVWdd

45
production).

T he

number

planktonic

of

a better

the

e x p l a n a t i o n of

in c o n t r a s t

t he m o s t

duction,

temperature

t he v a r i a t i o n
the question

of t h e d a i l y

incident

ments
Wetzel
apart

is r a i s e d as

r = 0.491

-2

(df = 9,

on th e

This c o r r e l a t i o n was

in t hi s

from September,
history of

p = 0.95,
196 8,

(Table

on t h e

4).

(H.S.,

on t h e

for t h e

those

of

1— 3 days

P = 0.95

light on those

p = 0. 9 5 df = 19).
the m e a s u r e d

same adjacent days,

df = 19).

stronger

same

Measure­

on L a w r e n c e Lake

to A u g u s t ,

the water was

primary production

to

l akes c a l c u ­

s t u d y and

l o w e r t h a n t h a t f or

primary production
(H.S.,

two

not s i g n i f i c a n t ) .

S e r i a l or a u t o c o r r e l a t i o n o f

r = 0.782

as compared

significantly r = 0.782,

a d j a c e n t d a y s was r = 0 . 4 5 9

r a t e s of

is d e t e r m i n e d

incubation periods

et a 1 . {in p r e p a r a t i o n )

(df 19).

con­

The correlation b e t ween estimates

of p r i m a r y p r o d u c t i o n

correlated

and p e r h a p s

to h o w m u c h of t h e

h i s t o r y of t h e w a t e r

radiation.

lakes w e r e

primary p r o ­

primary production

from overlapping

in l i g h t

in b o t h

in the r a t e s o f

of d a i l y p r i m a r y p r o d u c t i o n m

day was

p r o d u c t i o n ra t e s ,

Lake.

light and

the b i o l o g i c a l

lated

of

important variables explaining,

trolling,

by

a l g a e in D u c k L a k e w o u l d a f f o r d
the v a r i a t i o n

to L a w r e n c e

Since

control

i n c l u s i o n of c e l l v o l u m e a n d c e l l

1969,

T h u s on

these d a y s

the biological

in d e t e r m i n i n g

n e x t d a y or

t wo

the

than changes

46

TA B L E 4.

C o r r e l a t i o n b e t w e e n p r o d u c t i o n in L a w r e n c e Lake and Duck
Lake on the same d a y or a d j a c e n t days.

L a w rence L a k e
on the same d a y
(April to Aug.)

Duck Lake

Lawrence Lake
(present study)

L a w rence L ake
on the sam e o r
adjacent day
( S e p t .- A u g .)

L a w r e n c e Lake
(RGW) on a djac e n t
day s (Sept.-Aug.)

r — 0.491 ns

r = 0.612 HS

r = 0.654 HS

b = 0. 359

b = 0.406

b = 0. 390

n = 11

n = 22

n = 21

4 = 1.0

4 = 1.0

r = 0.782 H S #
b * 0.904
n

Note:

=

21

HS = h i g h l y s i g n i f i c a n t p > 0.01%
R G W = data c o l l e c t e d by W e t z e l et a l .,

(in preparation)

♦ A u t o c o r r e l a t i o n of light on t h e s e d a y s w a s r = 0.459 H S ,
b = 0.553, n = 21.

47

Algal

s e c r e t i o n of d i s s o l v e d

over almost

two annual

from

22 . 5 m g C m

m

—2

of
C m

0.0 t o
day

—1

( Fi g u r e s

day

—1

m e a n annual

day

in L a w r e n c e L a k e
—1

8).

when

increasing.

(Figures

secre t i o n was

The rates

of

exceeded

5b a n d

5.7%

the l a t e

q u a n t i t y of d i s s o l v e d
was maximal
except

at

hypolimnion,
(1969)

a late

caused
Algal

operative

a maximum.

organic

the

(Table

3).

to

l i g h t and

of

Here,

at

primary production

solved
(0.247)

(-0.253)

(0.447),

algal cell number

organic
and

by

carbon

annual

secretion

the

t o p of

by two m e c h a n i s m s ,

one
A

these two mechanisms.

oxygen

(0.289),

(0.271),

pH

with

the

(0.422),

light

(0.287),

and algal

cell

log

dis­

volume

negatively correlated with conductivity

and a l k a l i n i t y

t he

carbon

in t h e d a r k .

secretion was positively correlated

(0.360),

The mean

increased depth,

the other

correlation analysis confounds
Log

carbon remained

increase.

secretion occurs

in t h e

production

s u m m e r m a x i m u m of p a r t i c u l a t e

average

The

l o w but

carbon released

lm a n d d e c r e a s e d w i t h

at 10 m e t e r s

8) .

s u m m e r as p r i m a r y

secretion again reached

3.8 m g

secretion were maximal

b e g a n to d e c r e a s e w h i l e p a r t i c u l a t e o r g a n i c
high,

rates

of p l a n k t o n i c

the p l a n k t o n p r o d u c t i o n was

During

7.3 m g C

The maximum observed

in the e p i l i m n i o n
percentage

ranged

with a m e a n of

ph ot osynthesis never

primary production.
in A p r i l ,

—2

5a a n d

secretion during
—3

cycles

organic materials

(-0.229)

in 1968.

The

Figure 8.

Isopleths of algal secretion (mg C m
Lake, April, 1968-August, 1969.

-3

day

-1

) in Lawrence

E X T R A C E L LU LA R

0
1
i

P R IM A R Y

P R O D U C T IO N

i )'

3
(m)

4

s

4

DEPTH

7

I
*
10
II
II
FEB

MAR

APR

MAY

JU N

JUL

AUG.

SEP

OCT.

NOV

DEC

JA N

FEB

MAR APR

MAY

JUN

JUL

AUG

50
r e l a t i o n s h i p of

t he v a r i a b l e s d i d

cantly using the

1969 d a t a

that values

for c e l l

available.

Log

0.267

0.306

(P = 0.95,

number

organic

log o x y g e n

c a r b o n + 0.173

log c o n d u c t i v i t y

37% v a r i a t i o n

+ 1.56

showed

log s e c r e t i o n w a s

particulate organic
organic

carbon,

alkalinity,

and

that

light

In D u c k L a k e
summer

two weeks m

—3

at

settled cells at
m

—

2

following

A

a mean

the v a r i a t i o n

pH,

oxygen,

dissolved

cell number,

pH,

conductivity,

inversely but p r o ­

in p r i m a r y p r o d u c t i o n .
secretion increased

preceded
lm b u t

from

0 .1 2
of

in a n e a r l y

production.

The algal

p e a k s of p r i m a r y

not m

2— 3m w e r e

over t h e y e a r

stepwise

functional block

li g h t ,

—2

( F igures

responsible

t h e p r o d u c t i o n peak.

secretion ranged

of

conductivity,

{T a bl e 4).

p u l s e as d i d p r i m a r y

secretion maxima

A

by production,

a n d a l k a l i n i t y — c h a n g e d i r e c t l y or
to c h a n g e s

log

— 0.289 to e x p l a i n

cell volume,

temperature,

by

log t e m p e r a t u r e

40.2%

explained

carbon,

not

log c e l l v o l u m e +

log p H

of c o n f o u n d e d v a r i a b l e s — o x y g e n ,

portional

except

+ 0.561

in the d e p e n d e n t v a r i a b l e .

partial correlation
in the

135)

s e c r e t i o n m a y b e s t be p r e d i c t e d

log p a r t i c u l a t e c a r b o n — 0 .266

-1.144

df

signifi­

and cell volume were

log p r o d u c t i o n + 0 . 2 2 0

dissolved

not change

to

7a a n d

for t h e

7b).

—2

-2

day

—1

day
.

The

increase

Quantitatively

102 m g C m

1 0. 6 m g C m

p r o d u c t i o n by

—1

with

This

51
amounted

to

8% r e l e a s e o f t h e a n n u a l

primary production

compared

to

5. 7 % f o r t h e

in L a w r e n c e L a k e

(Table

2) .
The

June

highest

12 w h e n d a r k

senescent
settled
3m.

sa m e p e r i o d

secretion was

b l o o m of a l a r g e

loosely on

Much

between

extracellular release was

of

the

found on

associated with a

Botryococcus

t h e f r o n d s of

s p . that

the C e r a t o p h y l l u m a t

the d i f f e r e n c e

in m e a n a n n u a l s e c r e t i o n
_2
on a m
basis must be attributed

two lakes

to t h i s o n e d a t e a n d d e p t h

( F ig u r e s

Log

at a l l d e p t h s g a v e

secretion

in D u c k L a k e

positive correlation with

5a,

6,

7a,

and

significant

l o g s of p r i m a r y p r o d u c t i o n

(0.693),

cell

volume

(0.651),

particulate organic

(0.517),

temperature

(0.472),

algal

light

(0.434),

(0.410),

pH

(0.418),

(— 0.410)

log algal cel l

70% v a r i a t i o n
regression
between
rather

the

0.545

lakes was

indicated

se c r e t i o n was

of c o n ­

secretion

log p H + 0.58

The m a j o r

to a c c o u n t

for

difference

in t he

in s e c r e t i o n r a t e

the i n c l u s i o n of c e l l

in D u c k L a k e .

that

(0.442),

carbon

l o gs
Log

carbon

log p r o d u c t i o n

+ 5.54

to e x p l a i n v a r i a t i o n
two

t he

(— 0 . 4 0 9 ) .

c a r b o n - 7.57,

in s e c r e t i o n .

than cell v o l u m e

correlation

from
number

log p a r t i c u l a t e o r g a n i c

number

dissolved organic

and calcium

could be best predicted
+ 0.539

cell

an d n e g a t i v e c o r r e l a t i o n w i t h

ductivity

8).

71% of

number

A stepwise partial

the v a r i a t i o n of

e x p l a i n e d by log production,

log

cel l number,

52
p a r t i c u l a t e o r g a n i c carbon,
(Table 3).

Some

correlative

cation.

For

w e r e more
stratified
secretion
by

and

important

the

importance

lakes w a s

by c u m u l a t i v e

ductivity,

The most

th e s t r o n g d e p e n d e n c e

n ot

a n n u a l cycle
estimated

in t e m p e r a t e

Lago Maggiore.

Watt

bution control
season.
have

of

Storch

examined

representative

and
(Table

G o l d m a n e t a_l.

2 8 parameters
evaluated

secretion on

and Saunders

secretion over

ha s

through a complete

lakes.

over

the diurnal

the

on

the depth d i s t r i ­

four d a t e s

G o l d m a n found

(1968)

14 d a t e s

in the

( u n p u b l i s h e d da t a,

exceeded photosynthesis during
general,

important difference

(G o l d m a n et al_. , 1968),

(1966)

se a s o n s .

(con­

in L a w r e n c e L a k e

investigated

s e c r e t i o n an d

is s t r a t i f i e d

often called the extracellular

p r o d u c t s of p h o t o s y n t h e s i s
previously not been

l a ke

e f f e c t s of

between cell number

s e c r e t i o n in D u c k L a k e a n d
secretion,

for

bu t c o n f o u n d e d b y t h e

th e

Algal

temperature

predominantly controlled

are modified

oxygen).

stratifi­

T h e m a g n i t u d e of a l g a l

p r i m a r y p r o d u c t i o n while

was

of v e rtical

in t h e r e g r e s s i o n a n a l y s i s

r a t e s of p r i m a r y p r o d u c t i o n ,

pH,

lay in t h e d i f ­

oxygen c o n c e n t r a t i o n and

L a w r e n c e Lake.

parameters which

between apparent

in th e t w o l a k e s

example,

in b o t h

and c o n d u c t i v i t y

of t h e d i f f e r e n c e s

factors

f e r e n c e in d e p t h

pH,

same
1971)

period during

that

secretion

spring and

that,

s e c r e t i o n correlated well w i t h decreases

in

in

3).

53
major
a mi
at

p h y t o p l a n k t o n groups.

Deutsche1

(1970)

always

Watt

(1966)

found

the m a x i m u m

the d e p t h o f m a x i m u m p h o t o s y n t h e s i s ,

present

phytoplankton

as d i d

light

1966 ),

density

(2)

in n a t u r a l

1966),

f r o m the

populations

(1) CC > 2

(high)

limitation

( N a l ew a jk o ,

low light intensity,

1969).

e n d s of t h e

and

(6)

(5)

grow t h rate

light

K,

(Nalewajko

secretion,

numerous
reaction,

Dark

and a dark

fixing

mitochondria

14

rather

in the c h l o r o p l a s t ,
and

(Fogg an d

fixation and secretion occur

c a r b o x y l a t i o n s , for example,
CC> 2 i n t o

at both

the o p e r ­

secretion w h i c h are under d i f f e r e n t controls
1966).

and

l o w cell

and pH c o n t i n u u m i n d i c a t e
a light

(3)

1966,

The h i g h p e r c e n t a g e r e l e a s e d

a t i o n of t w o m e c h a n i s m s ,

Watt,

the

high population density,

intensity

(4)

(Watt,

and Marin,

and

to be a f u n c t i o n of

by h i g h pH),

inhibiting

s e c r e t i o n or release

in c u l t u r e s

has been shown

W att,

secretion

st u dy .
High percentage

(e.g.

and Anderson

by

by the W o o d —We r k m a n

four carbon

acids

in the

th an i n t o

three carbon phosphates

as

light m e d ia te d

in t h e

fixation

secretion.
Natu re]

w i d e range of

populations

secretion rates:

on Lake Onta r i o

1969),

(Watt,

10-500%

1 96 6 ),

have a

2 3 — 76% i n a d i a t o m b l o o m

(Nalewajko and Marin,

English reservoirs
(Watt,

in e u t r o p h i c w a t e r s

1969) , 1 — 33%

27% in th e

in L a g o M a g g i o r e

in

North Atlantic

( G o l d m a n e t a l .,

54
1968).

In t hi s

release

(PER)

study the p e r c e n t a g e

or p ercentage

extracellular

secretion during periods

of n o r m a l

l i g h t —m e d i a t e d g r o w t h w a s q u i t e

lm:

in L a w r e n c e

6.0%

Lake and

6.1%

in D u c k Lake

I s e c r e t i o n o n al l d a t e s
x
P E R = -=---- .---------- ^-- ----------- — -q— tE p r i m a r y p r o d u c t i o n o n a ll d a t e s
annual

basis

for e a c h m ^

of

L ak e p r i m a r y p r o d u c t i o n a n d
were secreted.

However,

La k e at m o s t o f

the depths

surface,

sampled

as t h e m e a n o f

P E R of a l l d a t e s

of L a w r e n c e

7

PPR

the

f rom the average

(including all depths)

In L a w r e n c e L a k e t he

Expressed

(-- ^-- ) , 2 3 . 5 % o f

secreted

10.5% on Duck Lake

in L a w r e n c e

because more depths

secretion mechanisms.

particulate production was

to

5.7%

_
O n an

a nigher PER occurred

by d a r k

compared

,„„
100.

(mean

8. 0 % of D u c k L a k e p r o d u c t i o n

were dominated

determination

low at O and

of L a w r e n c e L a k e

(Table

as

3).

percentage

secreted

with d e p t h w h e n p h o t o s y n t h e s i s decreased.

The

increased
PER was

n e g a t i v e l y c o r r e l a t e d w i t h p r i m a r y p r o d u c t i o n at b o t h
and

10 m e t e r s

were

so low,

day

, was

(P — 95%).
the

Because

secretion,

high relative

although very

to t h e

l o w in pg C l ' * '

l e v e l s of d a r k

as

t he

fixation

l o w e s t at t h e

surface,

production decreased.
p o i n t s of

apparently

However,

high percentage

(Figure

9).
secreted

increasing when

there were

release

With

production

In D u c k L a k e t h e p e r c e n t a g e of p r o d u c t i o n
was

rates

to t h e p r i m a r y p r o d u c t i o n .

increased d e p t h the PER incre a s e d
decreased

the p r o d u c t i o n

0

at h i g h

sufficient
production

to

Figure 9,

Isopleths of the percentage extracellular release (PER)
in Lawrence Lake, April, 1968-August, 1969.
Ul

(m )

PERCENT

RELEASE

®»

D E PT H

4

EXTR AC ELLU LAR

SO
FEB

MAR

APR

MAY

JU N

JUL

AUG

SEP

OCT

NOV

too

-K»
DEC

JAN

FEB.

MAR

ARR

1-0" -4C:',0
MAY

JU N

JU L

joa
AUG

57
make

the apparent

inverse relationship between p r o ­

duction and percentage
(Table
were

2).

The p o i n t s

40% o n November

at Om,

and

of h i g h e s t p e r c e n t a g e

6 — 21,

18% o n S e p t e m b e r

these dates

and d e p t h s

c el l n u m b e r s w e r e
between cell

number

f ro m 0-lm;

0.44 2 w h e n

the d a t a

lm,

8 at

2m

(Figure 10) .

h o we v e r ,

this

f r o m 3m w e r e

c el l v o l u m e and log c e l l

decreased

nu m be r

possible.

a

showed t h a t p r oduction r a t e s

T he

greater

(r =

0.371)

separation

correlation

and algal

cell

so t h a t p r i m a r y

of c e l l

in

volume on all dates and depths.
nu m be r s u g g e s t s t h at

f r o m small p h y t o p l a n k t e r s

c el l v o l u m e )

Because

number explained more variation

th a n d i d c e l l

importance

A partial

and d ependent,

at

log p h y t o p l a n k t o n

statistical

analysis

secretion

It w a s

in D u c k La ke

effects was

and c e l l

to r =

(Figure 6 b ) .

of t h e i r

production

On

The c o r r e l a t i o n

included.

(r = 0.563}

volume were confounded

22

the p h y t o p l a n k t o n

a lower c o r r e l a t i o n b e t w e e n

in L a w r e n c e L a k e

19% o n M a y

algal s e c r e t i o n w a s r = 0 . 6 9 5

plankton blooms decomposed

there was

t ha n

at

in every c a s e

and

secretion

1968,

l a r g e or i n c r e a s i n g .

(P - 0.95)

3m t h a t

secretion n o n — significant

t h a n l a r g e ones,

secretion

(lar ge s u r f a c e

except

when

the

is

area/

latter

are s c e n e s c e n t o r d e c o m p o s i n g .
This
K al f f

result

(1967),

agreed with Sa v a g e

and o t h e r s who showed

photosynthetic activity

(1969),

Watt

that most of

in the p l a n k t o n

is i n t h e

(1969),

the

Figure 10,

Isopleths of percentage extracellular release (PER)
in Duck Lake, 1968-1969.
Ln

00

PERCENT E X T R A C E L L U L A R R E L E A S E
■
\ : 11 ii1 '

DEPTH

(m)

0

1

■»

40
/V.'

58

2

lOj 20 106

1020

4

4

r-s

10

/■
Y
\

'■
■'

,v/

/'

(

■

Spltti

4

\

./

w,

3

Tm'"\V--

"

■LZ
SEP

OCT

vv

I1 A

1

i

r !

i

40

l
NOV

16

I

.

i

i
DEC

JAM

1
FEB

MAR.

APR

MAY

JUN,

JUL.

AUG. SEP

60
nannoplankton.
with C

14

organiccarbon

and,
14

C

These

small algae are

therefore,

than

probably

larger cells

secreted more

in w h i c h t h e

fixation per unit cell
High percentage

labelled rapidly

carbon

r a t e of

is s l o w e r .

secretion occurred when

w a s a 70% p h o t o i n h i b i t i o n o f p h o t o s y n t h e s i s
O n 11 d a t e s
PER was

in L a w r e n c e L a k e a n d o n e

higher

duction was

at

0m t h a n at

lower at

0m t h a n at lm.

enhanced

PER,

occurred

in the d a r k l y

(Watt,

in D u c k

1m, w h i l e

there
1 966).

Lake,

the

the primary p r o ­

Few observations

of

c a u s e d p o t e n t i a l l y by p h o t o i n h i b i t i o n ,
stained waters

of

Duck Lake where

the c o e f f i c i e n t o f l i g h t e x t i n c t i o n w a s m u c h h i g h e r

than

in L a w r e n c e Lake.
The
been

r a p i d d e a t h or d e c l i n e o f p l a n k t o n n u m b e r s

associated with high

The h igh h y p o l i m n e t i c
Lake

in l a t e August,

may have
and

been

percentage
1969,

partially decomposing

study

case,

at

was not

an d

secretion

in L a w r e n c e

in D u c k L a k e

on

least,

^ day

the d a r k

l ight b o t t l e

3 June

The

biomass of Botryococcus

the h i g h e s t

(200 m g C m

that of the

(G o ldman et a l . , 196 8) .

the r e s u l t o f t hi s m e c h a n i s m .

in D u c k L a k e had
the

PER

settled
at

3m

secretion recorded during
.

However,

fixation and

in the

latter

release equalled

indicating th at this

the light mediated.

has

secretion

61
B.

Diurnal P a t t e r n s of Photosy n t h e s i s
and Secretion

In o r d e r
expanding

to

t es t t h e d i u r n a l

short-term incubations

o n t h e f r a c t i o n of the
th e p e r i o d as

is d o n e

Lawrence

and Duck

Lawrence

L a k e at

0800-1200

and

incubations,
C m

—3

day

realized
between
may

—1

lakes.
lm,

On

1 2 - 1 3 June,

1968,

hours
as

(F i gu r e 11).

sum of the s h o r t - t e r m

e q u a l l e d 3 3 .6 m g C m

, respectively;

20 00 h r s

sunny conditions
25 A p r i l ,

12,

Table

—3

day

—1

and

1. 3 1 m g

th e b e s t e s t i m a t e w a s

(Table

6),

secretion was

rain

secretion

This u n u s u a l result

in t h e m o r n i n g

a day with

p r o d u c t i o n and

(Figure
100%

sunshine

fixation

again

The percentage organic

i n the m o r n i n g ,

towards dusk.

decreased

W h e n the d a r k

and release w e r e subtracted,

of PER lost

its s y m m e t r y .

The

2m in

slightly

towards m i d ­

d a y w h e n r a t e s of p r o d u c t i o n w e r e t h e h i g h e s t ,
increased

and by

11).

s e c r e t i o n at

at m i d d a y a n d w e r e

1200-154 5 period.
high

5).

all a f t e r n o o n

1969,

Duck Lake were maximal
in t h e

in

The primary

f r o m the e x p a n s i o n of p r o d u c t i o n a n d

On

higher

short-term

p h o t o s y n t h e s i s was m a x i m a l between

secretion,

1 6 0 0 and

(Figure

of continuous

the d a y l i g h t hours were m a d e on

h a v e b e e n c a u s e d by h e a v y

mostly

to th e e n t i r e d a y b a s e d

insolation received during

a series

1600-2000

p r o d u c t i o n and

of

for p r i m a r y p r o d u c t i o n m e a s u r e m e n t s

( V o l l e n w e i d e r , 1965),
incubations during

total

factor method

bottle

the d i e l

p a t t e r n of

and

pattern

PER observed

62

Figure

11.

D i u r n a l p a t t e r n of p r i m a r y production,
algal secretion, percentage secretion over
s h o r t , n o n — o v e r l a p p i n g i n c u b a t i o n s a t lm,
L a w r e n c e L a k e , 12 J u n e , 19 6 8 .
The solid
l i n e c u r v e is i n s o l a t i o n r e c e i v e d , 304 k c a l
m “ 2 / solid bars are primary production,
d a s h e d b a r s — t h e a l g a l s e c r e t i o n ( b o t h in
yg C 1 — 1 p e r i o d - ! ) , t h e d o t t e d l i n e — p e r ­
centage extracellular release during each
incubation period.

EXTRACELLULAR
*

#

o rt n - J

(s « « t rt h -

a 9d

9

n

0

P P uflC r '
n

0

0

_

*

D

( J O 6" Nouonaoad

Aavwiad

TABLE 5.

Dirunal pattern of primary production and secretion 12-13 June 1968;
Lawrence Lake at lm.

Particulate
production
period
mg C m"^

Secretion
per
period
mg C m"3

0448-0800

2.81

0800-1205

Incubation
period*

Estimated daily total
from diurnal factor

PER
(%)

Particulate
production
per day

Secretion
per day

0.19

76.74

3.06

3.99

12.96

0.38

62.40

1.83

2.94

1205-1605

9.29

0.33

17.14

0.62

3.61

1605-2022

7.53

0,38

33.75

1.71

5.06

2022-2403

0.64

0.06

100.73

9.51

9.44

2403-0450

0.33

0.04

33.56

1.31

Totals

•

»

•

»

*The day was rainy until noon; the sun shown intermittently during the
afternoon.

12,84
3.92

65

Figure

12.

Diurnal pattern of primary production,
alg a l s e c r e t i o n , PER, g l u c o s e h e t e r o t r o p h i c
u p t a k e p o t e n t i a l (Vm a x ) , a n d t h e m a x i m a l
estimate of natural substrate concentration
o f g l u c o s e (as ug C 1 “ 1, D u c k L a k e , 1m,
25 A p r i l , 1969) .
Upper:

--- e

Lower:

—•
— — —
-------------

g l u c o s e Vm a x :
in ug C 1-1

K t + Sn

p r i m a r y p r o d u c t i o n (ug C 1 ^
p e r i o d ~ l ) w i t h 90% c o n f i ­
dence interval
algal secretion
percentage extracellular
r e l e a s e (PER)
_^
i n s o l a t i o n (569 c a l m
day
)

33 APRIL A ?

30

°0

GLUCOSE

C I'V’

66

Vm a*

10

ofl

C

I '1

34

34

PER

16 C
- -6

L-

PRIMARY

PRODUCTION

72

'■"•o

0*O
0.4 —
0.3 “
300

400

600

*00

>OO0

1300
TIME

1400

MOO

MOO

3300

0

67

TABUi

6.

Diurnal
at

Incubation

125

ml

0835-1205

1200-1540

1535-1945

short

extracellular

release

25

April

1969;

Duck

Lake

term

Estimated from
Diurnal Factor

Secretion
per
period
mg C m"^

Part,
prod,
per day

Secretion
day_l

PER
%

incubations:
13.93
0. 2 7

1.004
0.182

116.67

L
D

26. 86
0.428

1.293

69.07

3. 3 2 5

0. 3 9 6

4.813
92.54

L
D

29.64
4.443

1. 3 4 5
0. 0 5 9

72.03

3.263

4 .5 8 1

L

14. 7 5

0.775
0.181

140.36

0.688

Total Particulate
P r i m a r y P r oduction as
the s u m of all light
bottles
Total Particulate
Primary Production
the s u m of light
dark bottles

ml

and

L
D

D

1000

production

Particulate
production
per period
mg C m - ^

period

bottles,

0537-045

primary

lm.

7,22

8.421

67.21

1 . 33
7 .3 7 1

5.25
26. 35

8 5 . IB

4 .417

5. 1 0

79. 35

3 .599

4.53

as

minus

bottles:
Amounts

per

period are
consecutive

determined
s a m p l e s in

by difference
the c a r b o y

between

540-845

14.91

0 . 4 36

112.30

2 .722

2.924

850-1210

20 .99

1 .048

7 1 . 55

2 .957

4.133

1205-1545

2 3 . B5

0.8B1

6 7 . 34

2.666

3 .958

1545-1945

14 . 9 5

1 .004

75,10

3. 3 8 7

4 .5 1 0

Total
i n 14

74 . 70

3. 3 6 9

Production
hour incubation

4.511

68
d u r i n g p e r i o d s of l o w p r o d u c t i v i t y d u r i n g t h e m o r n i n g
a nd a f t e r n o o n
cellular
of

14

g av e

included

t h e c o n t r i b u t i o n of a h i g h e x t r a -

r e l e a s e of o r g a n i c —

^^2 *

14

incubations

agreement

to the s u m o f

incubations

in small

bottles,

lative p r o d u c t i o n and
(Table

period w e r e

6).

from t h e

Secretion

the day w a s

l ower

the

incubation

period probably

two e x p e r i m e n t s

incubation in

the

at the e n d o f

incubations.

s e c r e t i o n m a y be e x p a n d e d

The

as

t h e u t i l i z a t i o n of

indicate

f a c t o r w i t h a b o u t the

incubations

at n ea r m i d - d a y g i v e

same

1936).

t h a t s e c r e t i o n and

t h e d a y and

to the d a i l y

the d i u r n a l

the

extended

(Z ebell a n d A n d e r s o n ,

follow one another over

proliferation

Measurement

short-term bottles

increased

s e c r e t i o n s by b a c t e r i a

amount

in a 1 l i t e r

t h a n the s e c r e t i o n m e a s u r e d

short-term bottle

m a t e s of t h e

cumu­

production per

in the c a r b o y

s u m of t h e

These

of

long-term

carboy agreed.
24%

period

th e e n t i r e d ay .
s u m of

short-term

and c o m p a r e d with

estimates

to

from t h e

production

production

the s h o r t - t e r m

in d i s c r e t e

secretion per

Both

expanded

of p r o d u c t i o n

algal

to the w h o l e day

(cf. a l s o V o l l e n w e i d e r , 1965).

Production was measured

and

the dark a s s i m i l a t i o n

T ^ e 1200— 1540 period ex panded

t he b e s t

carboy

C by

total
erro r.

that

b y u s e of
short-term

somewhat higher e s t i ­

s e c r e t e d by n o t a l lowing b a c t e r i a l

and u p t a k e

to d e v e l o p .

69
C .

Annual

Budgets of Primary
and Secretion

The m e a n annual p r o d u c t i o n and

Production
s e c r e t i o n at e a c h

d e p t h w e r e m u l t i p l i e d b y t h e v o l u m e of w a t e r
above and b e l o w the
totals

i n c u b a t i o n de p t h ;

for e a c h d e p t h of

surface area of

the

mary production and

lake;

is m e a n d a i l y p r i —
2
s e c r e t i o n pe r m e t e r
of s u r f a c e a re a .
times

of p a r t i c u l a t e o r g a n i c

column

for t h e ye a r .

t h a n in L a w r e n c e L a k e

(6,100 v s

assuming equal

entire

a r e a of t h e

e t a l ., in p r e p a r a t i o n )

sampling

from weekly

larger

surface area,

Lake was

2,400

kg C

greater

lake ^ y r

^,

pr od uctivity beneath the

independent studies
closely

similar

frequency

(Wetzel

(Table

in 1 96 8

7).

and

i n the W e t z e l

in o l i g o t r o p h i c
to y e a r

Lawrence Lake

th a n in D u c k L a k e or

and c a n change
Extracellular

photosynthesis

the

are

study reduced

amounted

to

3 . 88 g C m

—2

Apparently,

is m o r e s t a b l e

in s m a l l
brief,

final estimate

r e l e a s e of o r g a n i c

Primary

1969,

t o biweekly b e t w e e n those years.

ponds where high production periods
missed,

in the w a t e r

lakes.

agreed

production estimates were

from year

t he e s t i m a t e d

e s t i m a t e s of p r o d u c t i o n of L a w r e n c e L a k e b a s e d

the two c o n c u r r e n t a n d

production

production

in D u c k

respectively),

although

365 g a v e

B e c a u s e of t he

t he t o t a l p r i m a r y p r o d u c t i o n

on

by the

th e r e s u l t

budget

The

s u m of t he

12 m e t e r s w a s d i v i d e d

The mean d a i l y m e a s u r e m e n t

surface

the

in 0 . 5 m

tundra
easily

( K a l f f , 1967) .

carbon during
yr

—1

in D u c k L a k e

TABLE 7.

Annual budgets of primary production and secretion in Lawrence and Duck Lakes.

Lake/Date

Mean daily
primary production
mg c m“2 day"^

Mean daily
secretion
mg C m"2 day“l

Total Annual
primary production
g C
yr-l

Total Annual
secretion
g C m'2 yr”l

118.6
128.1

6.1
7,3

43.3
46.7

2.7

Lawrence Lake
Present study
1968-69
Apr.-Apr.
Aug.-Aug.

-j
o

Wetzel et al.
1968-69
Jan.-Jan.
Apr.-Apr.
Aug.-Aug.

138
121.5
124.5

50.7
44.4
45.4

1969-70
Jan.-Jan.

115.7

42.2

Duck Lake
1968-69
Sept.-Sept.

132.5

10.6

48.4

3.9

71
and

slightly

over the
during

less,

sa m e

2.66 g C m

interval

and

—2

yr

—1

in L a w r e n c e L a k e

sampled o n

the s a m e d a t e s

the most p r o d u c t i v e p o r t i o n of the year.

d i f f e r e n c e was primarily a result of
observed

secretion

in the d a r k

at

Th e

the e x t r e m e l y h i g h

3m on

3 June,

1969,

in

Duck L a k e .
D .

Zooplankton Excretion

Zooplankton grazing

and

subsequent

excretion

of

n i t r o g e n and p h o s p h o r u s m a y be a p r i m a r y p a t h w a y of
mineralization

in m a r i n e

systems

Physical

d i s r u p t i o n of c e l l s

releases

dissolved

order

to evaluate

affecting
term
200

zooplankton
14

densities

(Brehm,

r o l e of

Lake w a t e r

1967) .

to

250 ml

bottles

phytoplankton.

in

short­

to 4 0 , 1 0 0 ,

a nd
containing

The Daphnia

s w i m m i n g p oo l

( K a l a m a z o o Co.,

t ow s s o m e m o n t h s

initially

Michigan)
earlier.

and

The bottles

The p h y t o p l a n k t o n p r o d u c t i o n and
The

and counted

8900

zooplankton were
for

14

C uptake.

Gull

innoculated with

at

were measured.

t a b l e at

filled with

on a r o t a t i n g

weighed,

In

zooplankton

incubated
25°C.

feeding

secretion during

equivalent

1 ^ were added

1 9 68 ) .

and D a p h n i a m e n d o t a g a l e a t a w e r e c o l l e c t e d

from a outdoor

plankton

carbon

r a t e s of

and natural

schedleri

zooplankton

the p o t e n t i a l

the m e a s u r e d

incubations,

50 pCi

organic

by

(Johannes,

lux for

were

4 hours

secretion

s i e v e d o u t,

dried,

72
Plankton secretion

in b o t t l e s w i t h

h i g h c o n c e n t r a t i o n s of a d d e d a n i m a l s

the u n u s u a l l y

showed

PER compared

to the c o n t r o l s

but

n o t c l e a r w i t h l o w n u m b e r s of D a p h n i a

t hi s w a s

(Table 8).

Grazing pressure also

am o u n t of prim a r y
of

40,

(o n e - w a y A N O V A ,

increased

100,

organisms,

seriously reduced

1

However,

zooplankton grazing could

E.

the

by

14

C method and

important

was

algal cell
In a l g a l

required

and c o m p e n s a t i o n

(Hellebust,
that

night-time

the n i g h t

in

1 965).

and

then

However,

the

equals

light— fixed

24-hour

30% o f

in

Saunders

in s i t u

If t h e d a y l i g h t r e s p i r a t i o n w e r e
respiration

for

14
. . .
C — r e s p i r a t i o n is

for

15% of

cultures,

production

production

Storch

on the average

respired during

bations.

1965).

carbon

no correction

(Ryther an d M e n z e l ,

phytoplankton communities

decomposition,

reported

c a r b o n c a n be

in p a r t i c u l a t e c a r b o n e q u a l l e d

dark respiration
natural

standing crop of

by n e t p r i m a r y p r o d u c t i o n .

measured

significantly

Algal Cel l Carbon and P a r t i c u l a t e
Organic Carbon Replacement
B a s e d on P l a n k t o n i c —
photosynthesis

from

increases

not

secretion.

The replacement of algal cell

divided

if t h e s e e f f e c t s

p r o p o r t i o n a t e l y to t h e n a t u r a l d e n s i t y o f

a f f e c t p r o d u c t i o n or p e r c e n t a g e

estimated

the

p r o d u c t i o n at the e f f e c t i v e d e n s i t i e s

200 a n i m a l s

were reduced

P = 0.95)

the

equal

14

C

incu­
to the

total c a r bo n

f ix e d

73

TABLE

8

.

E f f e c t of z o o p l a n k t o n g r a z i n g o n r a t e s
carbon fixation and o r g a n i c secretion.

N u m b e r of a n i m a l s
1-1

200

N u m b e r of a n i m a l s
/250 ml b ottle

5C

D r y w t of a n i m a l s
( m g )/ b o t t l e
Primary production
(cpm/50ml)
S e c r e t i o n by a l g a e
(cpm/50ml)
Percent

1.0 4
2930.

secretion

100

40

0

25

10

0

0.47
4951

106.2

5 4 .3

4.00

of a l g a l

1.10

0.29
5596

0
7862

51.5
1.34

73.3
0.94

(%)
N ote:

All values

are

the m e a n o f

triplicates.

A o n e - w a y A N O V A s h o w e d t h at t h e p e r c e n t s e c r e t i o n w a s
s i g n i f i c a n t l y d i f f e r e n t for, at l e a s t , o n e o f the a n i m a l
densities.
O b s e r v e d F = 14.96.,, ^
c r i t i c a l F = 8. 45
for P = 0.99.
J '

74
per d a y w o u l d be respired.

The daily
14

POC w a s e s t i m a t e d by the m e a s u r e d
minus

30%

for daily r e s p iration.

value

for

l o s s by r e s p i r a t i o n

not acco u n t

carbon

in M a r c h ,
mean

of

C-primary production

On the average

seasonal changes.

the total s uspended particulate

in the e p i l i m n i o n r a n g e d

1970,

to

2800 m g m

1491 m g C m

—2

f r o m 694 m g

^ in J u n e ,

(Figure 1 3 a ) .

1969,

The

replacement

time based

from

544 d a y s w i t h a m e a n of 4 0 . 7

8.1

to

April,

1968-April,

ranged

from

of

8

_

2

mary production
1. 06 d a y s

1969

a n n u a l m e a n of

in o n l y

1050— 18,990 mg C m
16a)

and was

days

with

—

of

fluctuated

17a,

from

Table

calculating

0.30

(mean

2

; its

days

from
carbon

replaced

by p r i ­

1968)

or

of

an e s t i m a t e d

standing crop varied
—

2

)

17a,

17 d a y s

every

Table

1 4 6 — 2 1, 0 3 0 m g C m
replacement

from

(Figures

production

(Figure

mean

a mean

14a).

Minor differences

algal

or

2.25 d a y s w i t h a m e a n

by p r i m a r y

3.5-90.8 days,
9).

turnover

A l g a l c e ll

It w a s

2990 m g C m

64 d a y s

—

to

( Fi g ur e

between

m e a n of 1968 mg C m
varied

2

-2

with a

i n the e p i l i m n i o n w i t h

13a).

the P O C

replaced

a mean

-2

to D e c e m b e r ,

3.6 d a y s

In D u c k L a k e

carbon

( Fi g ur e 14a).

(Figure

(from A p r i l

C m

on primary production varied

3 0— 241 m g C m

3.4 m g C m

this

is p r o b a b l y h i g h a n d d o e s

for t e m p e r a t u r e d e p e n d e n t

In L a w r e n c e L a k e
organic

n e t a c c u m u l a t i o n of

— 2

and

1 1 — 361

9).

Cell

with a

turnover
(Figures

in t h e m e t h o d

cell v o l u m e undere s t i m a t e d

15

time
16a and
of

those

75

Figure

13a.

P a r t i c u l a t e o r g a n i c c a r b o n (------- )
(mg C m “ 2 x 10^) a n d a l g a l c e l l c a r b o n
(------- ) (mg C — 2 x 10l) i n L a w r e n c e L a k e ,
1968-69.

Figure

13b.

P a r t i c u l a t e o r g a n i c c a r b o n (------- )
(mg C m — 3 X 102) a n d a l g a l c e l l o r g a n i c c a r b o n
(------- ) (mg C
m “ 3 X 101) a t lm in L a w r e n c e
L a k e , 1 9 6 8 — 1969.

C "fl m'W

mg m J ilO

au.

cmoamc

c m k n

q * g * n ic
MKnCULATE •— * 1

■* ■*->• «

C m« *-*.«■

r _

‘)3M>*HV T

MRnCULATE OWJANC
n C ( L l CAJWON

77

Figure

14a.

T u r n o v e r o r r e p l a c e m e n t t i m e (days) o f
a l g a l c e l l c a r b o n (— ----- ) a n d p a r t i c u l a t e
o r g a n i c c a r b o n (------- ) b y p h y t o p l a n k t o n
p r i m a r y p r o d u c t i o n (m in us 3 0 % f o r r e s p i r ­
a t i o n d a y “ l) p e r m 2 o f t h e 0 — 5 m s t r a t u m i n
L a w r e n c e L a k e , 1 9 6 8 — 1969.

Figure

14b.

T u r n o v e r o r r e p l a c e m e n t t i m e (days) of
a l g a l c e l l c a r b o n (------- ) a n d p a r t i c u l a t e
o r g a n i c c a r b o n (------- ) b y p r i m a r y p r o ­
d u c t i o n ( m i n u s 30% for r e s p i r a t i o n d a y - i) a t
l m in L a w r e n c e Lake, 196 8 — 1 9 6 9 .

7 8

uiwitNa i

PtfTCULATE
one

«

C
TuBNOVEft

td**>

W * OCT

NOW

OCT

LAW RENCE

NOW DfC

L

JAM

1**"

14

SEP

Ffa

Figure 15.

Isopleths of particulate organic carbon (g C
Lake, 1968-1969.

PARTICULATE

ORGANIC

CARBON mg L

r

C
DEPTH

/

SEP

'W

OCT

O

NOV

DEC

JAM

FEB

MAR

APR

MAY

JUN

JUL.

AUG

SEP

81

Figure

16a.

Figure

16b.

P a r t i c u l a t e o r g a n i c c a r b o n (--------)
(mg C m ~ 2 x 1 0 ^) a n d a l g a l c e l l c a r b o n
(--------) (mg C m ” 2 x 1 0 3) i n D u c k L a k e ,
1968-1969.

—3
P a r t i c u l a t e o r g a n i c (------- ) (mg C m
X 10
and algal cell c a r b o n (
) (mg C m _ 3 X
102)
i n D u c k L a k e a t lm, 1 9 6 8 — 1 9 6 9 .

2

)

8 2

A
0

DUCK

L

H *

Z *

vSEP

OCT

NO/

DEC

JAN.

FE B

M AR

APR. M A V

tn

JU N

JUL

DUCK

L

MAY

JUN

AUG

SEP

1m

CC

SEP

OCT

NO/

OEC

JAN

FEB

MAR

APR

JUL

AUG

SEP

83

Figure

Figure

17a.

T u r n o v e r o r r e p l a c e m e n t t i m e (days) o f
a l g a l c e l l c a r b o n (------- ) a n d p a r t i c u l a t e
o r g a n i c c a r b o n (------- ) b y p r i m a r y p r o ­
d u c t i o n (minus 30% f o r r e s p i r a t i o n d a y “ ^-)
p e r m e t e r 2 in D u c k Lake, 1 9 6 8 — 1969.

17b.

T u r n o v e r o r r e p l a c e m e n t t i m e (days) of
a l g a l c el l c a r b o n (------- ) a n d p a r t i c u l a t e
organic carbon (
) by primary pro­
d u c t i o n (minus 30% for r e s p i r a t i o n d a y “ l)
p e r m e t e r ^ at lm in D u c k Lake, 1 9 6 8 - 1 9 6 9 .

P A R T I C U L A T E & C E Ll*“ *ORGANIC CARBON
TURNOVER TIME
(ttoy«)
,
*

§ELL & PART ORG.

C

TURNOVER

(d s y t)

o T g ^ S S l S S a S S g S f
SEP
OCT
NOV
Dec
JA N .

X

FEB.
M AP.
APB.
JU N .

DUCK

MAY

DUCK

JU L.

85
TA BL E 9.

A.

Co m p a r i s o n of m e a n s t a n d i n g crops, rates, and r e p l a c e m e n t
times o f algal cell carbon, p a r t i cu la te and d i s s o l v e d
o r g a ni c c arbon pools in L awr e n c e and Duck L a k e s .

0-5 Meters
_2
Primary p r o d u c t i o n {mg C m
d ay
-2
-1
S ecretion {mg C m
day
)
-2
A l g a l cell c a r b o n (mg m
)

)

Algal cell c a r b o n replacement
Pa r t i cu lat e o r g an ic carbon
POC rep lac e m e n t time

(days)
-2
(mg C m
)

(days)
-2

Dissolved o r g a n i c carbon

(mg C m

)

Primary p r o d u c t i o n / a l g a l

cell c a r b o n

POC/ p r i m ar y pr odu ct ion

At

Duck Lake

102

132

n.a.

10.6

83

23 73

1.06

17.3

1492

2990

43

64

20458

18170
0.07

1.2
14.6

DOC/ p r i ma ry pr odu ct ion

B.

Lawrence Lake

22.6

204

138

POC / algal cell carbon

18

2.7

DOC / algal cell carbon

247

7.1

37

71

1 Meter
P r i m ar y p r o d u c t i o n (mg C m
day
-3
-1
Secretion (mg C m
day
)
-3
Al g a l cell c a r b o n (mg C m )

)

3.1
23

453

1

11

324

763

46

46

Al g a l cell c a r b o n replac eme nt
Pa rticulate o r g a n i c carbon
POC r e p l a c em ent time

(days)
-3
(mg C m
)

1.4

(days)

Dissolved o r g a n i c carbon

-3
(mg C m )

Primary pr od uct i o n / a l g a l cell c arbon
POC/ primary pro du cti on
DOC/ p r i ma ry p r o d u c t i o n

6635
1.4

882 5
0.16

8.7

10.8

180

124

POC / algal cel l carbon

14

1.7

DOC/ algal cel l carbon

288

19.5

86
turnover values
20%.

fro m Lawrence Lake,

Seasonal differences

as a p r o p o r t i o n

b u t b y no m o r e

in th e a l g a l c e l l

of t h e t o t a l c a r b o n

fixed,

than

respiration

and n o n ­

equilibrium conditions permitted only a relative com­
p a r i s o n of r e p l a c e m e n t o r t u r n o v e r

t i m e s b e t w e e n lakes.
3

The contrast between aerial and meter
of p a r t i c u l a t e

a n d algal

and Duck

revealed marked differences.

lakes

cell organic carbon

b i o m a s s of p h y t o p l a n k t o n
24 t i m e s g r e a t e r
in the e p i l i m n i o n
duction

was

twice

(0-5 m e t e r s )

found

and

2 0

lakes
(4)

rapidly
Thus,
volume
algal

times g r e a t e r per m ^

Lake,

—3

Duck

cell

carbon was

in L a w r e n c e Lake

algal cells

3

at

lm.

in D u c k L ake
(3)

Because

Lake was only twice

identical,

in the

46 d a y s

three

than in Duck Lake

two
a t lm.

times more
(Table

9).

p h o t o s y n t h e s i z e m o r e per uni t cell
in D u c k Lake.

In a d d i t i o n ,

v o l u m e d i d n ot c o r r e l a t e w i t h p a r t i c u l a t e

o r g a n i c c a r b o n as

it d i d

carbon concentration
t he c a r b o n

and m

turned over

in L a w r e n c e L a k e t h a n
cell

2

the t u r n o v e r of P O C

for t h e y e a r w a s n e a r l y

Algal

Lake was o n the av e r a g e

in L a w r e n c e L a k e .

the primary production m
that of Lawrence

(1) T h e

w h e r e m o s t of the p r o ­

in s u s p e n s i o n p e r m

that

in L a w r e n c e

t h a n in L a w r e n c e L a k e o n a n a e r i a l b a s i s

t o o k pl a c e ,

(2) T h e P O C

in D u c k

turnover

in D u c k Lake.

in b o t h

fl u x r a t h e r

t he p h y t o p l a n k t o n c r o p

Particulate

lakes vari e d d i r e c t l y wit h

t h a n w i t h the
(Table 9).

s i ze or v o l u m e of

87
F .

S e d i m e n t a t i o n of Particulate
Carbon

Particulate

organic

carbon

e p i l i m n i o n at r a t e s v a r y i n g
w i t h a m e a n of
Table

10).

77 m g C m

—2

from
day

settled

from the

7 -1 8 0 m g C m

— 1

(Figu res

—2

18 a n d

The m a x i m a occurred during overturn

and N o vember
in J u l y a n d

day

19,
in A p r i l

a n d d u r i n g p e r i o d s o f m a x i m u m s u s p e n d e d POC
September,

10 m e t e r s w a s g r e a t e r

1969.
t h a n at

The amount sedimenting
5 meters,

kept much organic material

to

except during

July-September when a sharp thermal discontinuity

et

—1

in t he m e t a l i m n i o n

a t 5m

( W etzel

a l . in p r e p . ) .
During

the

summer the p e r c e n t a g e o r g a n i c car b o n

decreased while

t h e p e r c e n t a g e b y w e i g h t of p r e c i p i t a t e d

CaCO^

( Fi gures

increased

2 0 a nd

highest percentage organic
or d u r i n g
was
At

resuspended

to a depth of several

carbon material

large amounts

centimeters

2 0 and

resulting

t h e ice

of C a C O ^ .

m a r l of

low organic

(Rich,

1970b).

This

the h i g h e r p e r c e n t a g e o r g a n i c
from algal decomposition

21).

Sedimentation
calculate

under

the

and the b o t t o m m a t e r i a l m i x e d

in e f f e c t d i l u t e d

(Figures

carbon occurred

and a u t u m n a l circulation,

content was

process

In g e n e r a l ,

low-production periods when photosynthesis

t o o l o w to p r e c i p i t a t e
spring

21).

of organic

c a r b o n m a y be u s e d

to

the n e c e s s a r y r a t e o f r e p l e n i s h m e n t o f P O C

b y p r i m a r y p r o d u c t i o n to m a i n t a i n

the observed

standing

Figure 18.

Dry weight of material in sediment traps day" at Station A and D
combined with 90% confidence intervals where n = 3 (mg dry wt.
m
day-1); five meter traps (------) and 10 or 11m traps
(

).

mo

DRY

W E IG H T

£
O
m

£
<

c

r~

1>
o
C

m

O
n

DEC
JAN
FEB.
MAR
APR
MAY

68

m~2 day

Figure 19

-2

-1

Organic carbon sedimentation rates (mg C m
day ) at 5m
(------) and 10 or 11m (------ ) in Lawrence Lake,
1969-1970.

v>
Q

FEB,

MAR

APR.

MAV

JUN

JUL

AUG

SEP

OCT

NO

DEC

JAN

FEB

MAR

APR

MAY

16

S
8
S
$
8
o

day’
m-2
CARBON
mg O R G A N IC

TABLE 10.

Sedimentation budgets, Lawrence Lake, 1 February 1969-27 January 1970 (361 days).

Station A

Station D

227.01

227,36

227.19

27.65

27.97

27.81

101.81

109.25

105.53 (248 days)*

338.66

315.96

327.31

34,88

29.98

32.43

152.37

152.45

Mean

Mean percent organic carbon

5 meters:
-2
g dry wt. m
„ -2
g Org. C m
g CaCO^ m 2

12.24%

10 and 11 meters:
g dry wt. m 2
g Org. „
C m “2
„ ™
g CaC03
m -2

152.41 (248 days)*

Annual Budget Estimates**

g dry wt. m 2 yr
„ -2
-1
g Org. C m
yr

9.91%

1

™
g ^CaC03
m -2 yr -1

5 meters

10-11 meters

229.68

330.91

28.11

32.79

145.12

196.44

♦The total from 248 days of sedimentation; 24 May 1969 to 29 April 1970.
**A11 figures increased to one full year.

Figure 20.

Percentage organic carbon of the dry weight of particulate
material sedimented with 90% confidence interval where
n = 3 at 5m (------) and 10 or 11m (------) in
Lawrence Lake, 1969-1970.

^
u

CARBON
ORGANIC
PERCENT

FEB

MAR

APR

MAY

JUN.

JUL

AUG

SEP

OCT.

NOV

DEC

JAN

FEB.

MAR

APR. MAY

Figure 21.

Percentage CaCC>3 of the dry weight particulate material sedimented
with {901 confidence interval where n = 3 at 5m (------) and
10 or 11m {------) in Lawrence Lake, 1969-1970.

^
UT

PERCENT

u
o

CaCOj
o
o

BY

W E IG H T

o»

CD

T
J3
D

JUN
JUL
AUG

..

SEP
OCT
NCV
DEC
JAN
FEB
MAR
APR

96

97
crop.

Davis

small

(1968)

shown that p o l l e n

lakes are r e s u s p e n d e d

deposited

at the gr e a t e s t

matter distributed
was

has

concentrated

thermocline.

from the

de p th s .

grains

s h a l l o w zones and

Small

particulate

u n i f o r m l y o n t h e s u r f a c e o f the

8— 14 t i m e s by t h e

time

it p a s s e d

R e d i s t r i b u t i o n of p a r t i c l e s

particles w e r e of u n i f o r m l y

Marl

small

size

at t h e d e e p e s t p o i n t

d e p o s i t s of

1 1 m in t h e

since

the Wisconsin glacial

BP.

Apparently,

resuspended
Rich

marl

in the

littoral

(1970b)

to a d e p t h o f

has

shown

littoral

growing

Allen

(1969b,

on r o o t e d

lake

Cores

transect profiles

by R i c h

(1970b)

1971)

plants

held

showed

0.5,

1,

2,

shown

in a n

is d i s l o d g e d
functionally

which remains

t a k e n at 1 2 m b y W e t z e l
a t 0,

has

in the

it a ct s

as a l a r g e p i e c e of p a r t i c u l a t e m a t e r i a l
littoral.

and y e t

are evidently

When this marl d e p o s i t i o n

b y w a v e a c t i o n o r d e a t h of th e p l a n t ,

in the

to be

presumably during

form a thick crust of m arl

organic matrix.

c a . 15000 years

that bott o m m a t e r i a l was m i x e d

in the s h a l l o w s .

zone

z o ne a n d

basin,

Larger pieces of marl

t h a t the e p i p h y t e s

lake.

small enough

the c e n t r a l

several centimeters,

thermal overturn.
retained

to

If m a r l

in L a w r e n c e

retreat,

is n ot u n i f o r m l y

an d c a r r i e d

the

t h e y s h o u l d be

9 . 5 m at t h e d e e p e s t p o i n t h a v e d e v e l o p e d
Lake

lake

in a l a k e is

o b v i o u s l y a f u n c t i o n o f s i z e of the p a r t i c l e s .

deposited mostly

in

3,

and

5, 7,

in

and

that smaller p a r t icles were

11m

deposited

at 12 m e t e r s .

hypothesized,

This

finer material,

o r i g i n a t e s by p r e c i p i t a t i o n o f s u p e r ­

s a t u r a t e d CaCO-j by p h y t o p l a n k t o n
solubility during
The

greater

material

g r o w t h or b y

the warmer m o n t h s

turbulence

in the

effects

observed with

phytic

in o p e n w a t e r .

community

The

littoral
Three

zone

(Wetzel,

lines o f evidence

for a p l a n k t o n i c o r i g i n of t h e
cent e r of
in t h e

lake.

summer was

weight,
the

the

to

t raps,

position during
however,

(1)

greater

decreasing

sediment

like

Toyoda

e^t al.

than

fine CaCO^

epiphytic

and macro-

1970) .
support

the h y p o t h e s i s

fine sediment

2 0

sediments

in

the

particulate material

% o r g a n i c c a r b o n by

5 m and

9.9% at

1 0 m in

biological

decom­

total dry w e i g h t

th a t s e t t l i n g m a t e r i a l w a s

the p o l l e n in F r a i n s
(1968)

pieces

up the m a r l b e n c h e s

bake

found a s i m i l a r

increased,
concen­

(Davis,

1 968).

increase

i n the

increased d e p t h

in its n i t r o g e n and p h o s p h o r u s

deep water

the c o n ­

the

build

a m o u n t of m a t e r i a l d e p o s i t e d w i t h
decrease

and

which indicates
The

th is

pollen must occur with

Suspended

12.2% a t

settling.

indicating

trated

Thus

forms larger o r g a n i c a l l y b o u n d

of m arl w h i c h e f f ectively help
in t h e

1969).

zo n e k e e p s

there.

s e d i m e n t a t i o n of p l a n k t o n d e t r i t u s
precipitated

reduced

( B r u n s k il l ,

littoral

from settling p e r m a n e n t l y

centration

i t is

content.

and a
T he

in L a w r e n c e L a k e ha v e a h i g h e r

centage organic weight

th a n s h a l l o w e r

sediments

per­

99
(Rich,

1 970b).

carbon

of

Thus,

surface

the p e r c e n t a g e o r g a n i c

sediments

i ncreased with depth,
th e

while

on

th e p e r c e n t a g e

s e t t l i n g POC decreased.

origin

with

is n o t
t im e

(2)

Sedimentation was correlated

standing
the y e a r

deposits

lags

c r o p of

in o r g a n i c

seston w i t h

Algal

carbon was

sestonic organic

particulate carbon
The r e l a t i o n s h i p

the thermal
maximal

discontinuity
biomass

lake w a s

synthesis would

a t w o —w e e k
the p r o b a b l e

lag

Maxima

(Figures

to changes
13a,

s o u r c e of t he

sedimented

and

i n the

production corresponded

carbon which

(3) M e g a r d

carbon

sediments.

s e d i m e n t a t i o n to d e e p e r w a t e r s .
in p r i m a r y

the

a different

significantly

p = 0.95) .

between production,

a nd

cell

and benthic

suspended

(r = 0.49,

and m i n i m a

while

suggests

littoral

stronger because of

seston,

This

lake

o r g a n i c c a r b o n in

f or

the

through

the b o t t o m of t h e

13b).

total

to t h e b o t t o m

stratified.
(1968)

estimated

that algal p h o t o ­

precipitate an additional

as p r e c i p i t a t e d C a C O ^ .

2 5 — 40% m o r e

The primary production

in

L a w r e n c e L a k e d u r i n g the s e d i m e n t a t i o n s t u d y w a s 6 8.5 g
_o
C m
a b o v e the 5m c o n t o u r s u r f a c e a r e a and 145 g C a C O ^
(17.4 g CaCO-j—C)

were

collected

from

the

5m s e d i m e n t a t i o n

t ra p s.

T h e r a t i o o f C a C O ^ -C s e d i m e n t e d

duction

in the e p i l i m n i o n = 17.4 g / 6 8. 5 g X 100 =

within

the r a n g e c a l c u l a t e d b y M e g a r d

Minnesota.

to p r i m a r y p r o ­

for m a r l

lakes

25%,
in

100
To determine

th e c o n c e n t r a t i n g e f f e c t o f

b a s i n o n the s e d i m e n t a t i o n of a l g a l
assumed

t h a t all

the

in th e e p i l i m n i o n
at t h e

The

of t h e 5 m c o n t o u r .
Assuming
ibr i um ,

th a t

decomposition
by

t h r o u g h the t h e r m o c l i n e

surface a r e a

Thus,

that

is t w i c e

the c o n c e n t r a t i o n

sestonic

organic

the c o n c e n t r a t i o n
is o c c u r r i n g ,

sedimentation

it w a s

settling o r g a n i c carbon produced

sedimented

5m c o n t o u r .

detritus

t h e lake

the

factor

is t w o a n d
turnover

t ha t no

of

POC

is:

-2
m e a n POC in ep i l i m n i o n 0-5m m
of 5m s u r fac e area
,
--------------- *■-------------------- — ------— ------------- = da y s
se di men ted organic c a r b o n m
d ay
at 5 m

The d e c o m p o s i t i o n occu r r i n g
ticulate

production m

settling

i n to

1969,

1 February,

to

in t he

the

7 4.5 m g C m

at

5m.
—2

—

2

— 1

above

22);

140 m g C m

—1

the

was

5m, m i n u s

traps.

(
—

2

14

is th e par —
the

amount

From 1 February,
2959 mg C m

C production

day

caught

traps s h o u l d

—1

.

2

therefore,

30%

An average

in the s e d i m e n t
have

minus

Average replace­

21 days.

tr aps

c a u g h t 15 6 5 m g

53 % of that p r o d u c e d .

is e s t i m a t e d ,

,
to deple tio n

the mean p r i m a r y pro-

production was

w h i c h is o n l y

production.

epilimnion

the m e a n P O C w a s

(Figure

day

In 21 d a y s

decomposition
POC

1970,

was

t i me by a l g a l

of

C m

day

of p a r t i c u l a t e m a t e r i a l

f or r e s p i r a t i o n )
ment

—2

in t h e

5m sediment

0-5m stratum

duction

is two.

c a r b o n i s at e q u i l ­

factor

then

the area

Epilimnetic

to be

47 %

of the

101

Figure

22.

R a t e s o f t u r n o v e r (days) o f p a r t i c u l a t e
o r g a n i c c a r b o n by s e d i m e n t a t i o n in
L a w r e n c e L a k e , 0 — 5m s t r a t u m (lower) a n d
standing crops of particulate o r g a n i c car­
b o n (mg C m — 2 x 103) 0 - 1 0m p e r m 2 s u r f a c e
a r e a at O m (------- ) a n d 0 - 5m p e r m 2 o f 5m
s u r f a c e a r e a (------- ) (upper) .

^QC

SEDIMENTATION

TURNOVER

'.aa/S '

STANDING

CROP

POC

-ng C ^ 2* to

102

350

RQ(~ O bm
a POC.

100

200

100

FEB

MAR

ARR

M AY

JUN

JUL

AUG

SEP

OCT

NOV

DCC

JA N

FEB

MAR

APR

M AY

103
T h e d i s a p p e a r a n c e o f POC u n d e r t h e
second method of e s t i m a t i n g d e c o m p o s i t i o n
epilimnion because

t h e r e wa s

ic e is a
in the

l i t t l e p r o d u c t i o n a n d no

r e s u s p e n s i o n of b o t t o m m a t e r i a l .
F r o m D e c e m b e r 22 to
_2
M a r c h 16 the POC m
in the e p i l i m n i o n d e c r e a s e d f r o m
—2
3506 to 1318 m g C m
. During the interval primary
production added
total
was

2 20 m g C m

observed decrease

2188

+ 220

decrease.

Thus

33% of

7 9 8 / 2 4 0 8 or

t r a p s if a ll

of the

the ice,

the

the

the t r u e p e r c e n t a g e o f
in the

A third

5m or

morphometry.
wa s

11m.

at

—2
— 1

been caught

that

that und e r
the

lost
Thus

l o s s o f POC
%;

the d e c o m p o ­

34%.

in the p e r c e n t a g e

organic

is

carbon

This procedure avoids assumptions

t r a p e f f i c i e n c y or c o n c e n t r a t i o n by t h e
On April

20.33% organic

to 1 5 . 1 7 %

to

6 6

a 65%

e s t i m a t e of e p i l i m n e t i c d e c o m p o s i t i o n

fr om

sediment

(0 - 5 m)

day

the b o t t o m .

traps was

The

t h r o u g h the

likely,

so r e s t r i c t e d

really closer

— 2

PO C h a d

the e p i l i m n e t i c

f rom d e c r e a s e s

about

loss of

anywhere on

calculated
0m to

9.17 mg C m

It is m o r e

5m s e d i m e n t

s i t i o n of P O C w a s

798 mg C m

lost POC s e t t l e d

circulation was
settled

5m level.

^ at 5m in 84 d ays ?

20 M a r c h or

5m i s o c l i n e .

POC c o u l d h a v e

caught

the

Sedimentation observed was
to

ar ea

above

in PO C in the e p i l i m n i o n

= 2408 m g C m

fr om 2 3 D e c e m b e r

in th e

_2

5m,

22,

1969,

the

c a r b o n by w e i g h t .

a r e d u c t i o n of

surface plankton
This was

5.16% o r

reduced

a 25. 4% c h a n g e

lake

104
i n the p r o p o r t i o n o r g a n i c c a r b o n b y d r y w e i g h t *
October

23,

carbon;

in the

in t he

l l m trap,

was

1969,

the

5m traps

this was

11.9% organic

8.46%/22.2% or a

organic

surface plankton was
reduced

carbon.

38% r e d u c t i o n

carbon by w e i g h t

in 5m.

viously
the

2 5 — 38%

The r e d u c t i o n

T h e s e two e x a m p l e s

estimated d o u b l i n g of the POC

contained

t o o high.

both living

precipitated CaCO^
underestimate

of

initial
the

respectively,
5 meters.

and

the s u r f a c e

seston

The p r e s e n c e of
seston would
an d

calculating decompo­
gave estimates of

34% d u r i n g

for the y e a r ,

the w i n t e r in t h e u p p e r

S e d i m e n t a t i o n was one of
carbon

the major

r o u t e s of

from the e p i l i m n i o n

L a w r e n c e Lake.
G.

Ice c o v e r
the

of

th e s p r i n g a n d

r e m o v a l of p a r t i c u l a t e o r g a n i c
of

through

true decomposition.

sedimentation

47% d u r i n g

the p r e ­

percentage organic carbon

independent methods

s i t i o n of POC d u r i n g
2 5 — 38% and

indicate

and partially mineralized

thus underestimate
Three

cells.

but d e c o m p o ­

sedimenting

However,

a nd d e a d

and

in the p e r c e n t a g e

in t h e e p i l i m n i o n m a y

5m c o n t o u r w a s

22.2% organic

to 1 3 . 7 %

p r o b a b l y d o n o t r e p r e s e n t t h e e n t i r e year,
s i t i o n of

On

lakes

remaining

Plankton Metabolism Compared
Whole Lake Respiration
in W i n t e r
from December

to g a s e x c h a n g e
from the

to

t h r o u g h m id M a r c h

closed

so t h a t o r g a n i c m a t e r i a l

preceding summer was oxidized

using

105
u nrenewed deep water concentrations

of dissolved oxygen.

A n e s t i m a t e of o x y g e n u t i l i z a t i o n m u s t
of s e d i m e n t e d p l a n k t o n r e m a i n s ,
aquatic plants,

leaf

fall

summer
The

O2

m

-2

day

—1

in the t w o

(C0

ratio)

or

2

1.0

(Rich,

excess

of

twice

ton

(T a b l e

C (>2

evolution

m

—2

the

— 1

day

equal

1970b).

the m e a n
11).

-2

to 0. 85

The

annual

Rich

—1

.

total

day

—1

(1970b)

found

It d r o p p e d

that

far

at t h a t

primary p r o d u c t i o n of

in

time

the plank­

the m e a n a n n u a l

Lawrence Lake was

to l e s s t h a n

200 m g C

but generally agreed with

r e p o r t e d here.

as the w i n t e r a d v a n c e d .

anaerobic

conditions

oxygen

—2

respi r a t i o n was

decreased

and

showed

It

tension can

t h e ice

is p r o b a b l e
organic

heterotrophs.

that the respiration

unimpeded when

under

lack of s u i t a b l e

slowed g r o w t h of aerobic

continued

m

Lake

(Manny et a l ., 1971)

T h e r ate of o x y g e n d e p l e t i o n

(1941)

Lawrence

284 m g 0 2

from the benthos of
day

1 9 6 8 — 69

if t h e r e s p i r a t i o n q u o t i e n t

during the winter,

results

strates

1969).

the p r i m a r y p r o d u c t i o n o c c u r r i n g

and

320 m g C m

was

and

had d e v e l o p e d

lakes:

and Duck Lake

little difference

i0

(Moss,

sources,

r ates o f o x y g e n d e p l e t i o n d u r i n g

It m a d e
2

the s e d i m e n t

stratification

were v ery nearly equal
2 97 m g

decomposing annual

from t e r r e s t r i a l

any r e m a i n i n g oxygen deb t
during

include oxidation

rate

sub­

Lindeman

in m i c r o c o s m s

oxygen b e c a m e depleted.

induce facultative

that

anaerobes

Decreased
to

106

TABLE 11,

Rtductian in ditiolv«d o x y g e n concentrations und e r the ice in Lawrence and Duck Lakes.

g 0 2 m -2

Change in (0? )
g m -^

Oj utilization
mg Oj m _2 d a y “ *

Prim a r y production
mg C irT2 d a y “ l

14.563/89 days

163 .6

33 .81

27,59/92 days

296-7

39.04

21.51/99 days

217.3

20.50

24 .66

15.11/49 days

314.0

28 Jan.

9. 55

7.058/30 days

2 35. 3

27 F e b .

2.49

22.69/7B days

284 .2

Lawrence

Lake:

1967-60
18 D e c .
18 Mar.

1-69
16 Dec.
27 Dec.
6 Jan.
20 Jan.
3 Feb.
17 Feb.
4 Mar.
17 M a r .

-70
22 Dec.
5 Jan.
19 J a n.
1 Feb.
16 Feb.
2 Mar.
16 Mar.
30 Mar.

74. 10
41. 01

74.91
71.22
69 .17
64. 10
56. 16
55.92
51. 51
47. 32

72.57
60 .60
63 ,50
59 .22
64. 13
51.13
51.H1
51.06

Duck L a k e :
1968-69
11 D e c .

60. 3

107
m e t a b o l i z e a n a e r o b i c a l l y or c h a n g e t h e
sition.

Thus,

it is q u i t e p o s s i b l e

depletion method

species c o m p o ­

that

the o x y g e n

reveals only m i n i m u m values of p r o ­

cesses.
Th e r a t e s o f o x y g e n d e p l e t i o n

and mean annual

r a t e s o f p r i m a r y p r o d u c t i o n in t h e w a t e r c o l u m n p e r m
were very

similar

in t h e s e

trasting morphology,
composition,

of

n u trient content,

and biomass.

atory metabolism

greatly c o n ­
hydrophyte

In b o t h c a s e s

species

the n e t r e s p i r ­

in w i n t e r w a s t w i c e t h e m e a n a n n u a l

plankton production,
interface

two l a k e s

2

showing that

the

s e d i m e n t —w a t e r

is t h e si te o f a l a r g e r c a r b o n

t h r o u g h t h e p h y t o p l a n k t o n in s m a l l

lakes

f lux t h a n
(see a l s o

Rich,

1970b).
H.

Dissolved Organic Carbon,
Sources and U t ilization

Total dissolved organic carbon
varied
with

f r o m 1.5

a m e a n of

frequency of

to 9.5 m g C
5.7 m g C l

over

(Figure

sampling was changed

in 19 69 t h e r e w e r e
(1)

1

I- 1

Its

in L a w r e n c e L a k e
a

2.5-year period

23).

Although

from weekly

to b i w e e k l y

similarities between

the y ear s.

Highest values were observed during

the s u m m e r

stratification
compared

in the

to 4-5 m g C

surface waters
1

1

at

12m.

(2)

(7— 9 m g C l 1 ) a s
T h e maximum stand-

ing crop of d i s s olved or g a n i c carbon

(DOC)

in S e p t e m b e r

the

and O c t o b e r

just before

th e

m

_2

occurred

autumnal mixing.

Figure 23.

108

Isopleths of total dissolved organic carbon (mg C l
) in
Lawrence Lake, 1967-1970. Sampling was weekly before 1969
and biweekly thereafter (cf. Wetzel et al., in preparation),

109

o

110

(3) M i n i m u m v a l u e s w e r e
d u c t i o n was

reduced

in

and

1 968 - 6 9 ,

Pockets

(1 m g C l -

3 m g C I-

1

the

ice w h e n pro­

in 1 9 6 7 - 6 8 ,

2 mg C l-

1

in 196 9- 7 0 ) .

1

of h i g h a n d

often continuing
with

found under

low concentrations

for several weeks,

occurred,

and w e r e c o rrelated

inputs of allochthonous organic carbon

or

intense

planktonic production.
T h e DO C

in D u c k L a k e r a n g e d

w i t h a m e a n of

8 . 6

mg C

1 ^

m e a n D O C of L a w r e n c e L a k e .
the

su mme r;

f o u n d at

however,

3m in

late

the

i ce

summer

24),

1.5

t i m e s the

High levels occurred during

a nd

early autumn of

discontinuity

to t h a t d e p t h .

1968 and

layer p r e v e n t e d c i r ­

Minimal values

occurred

under

in J a n u a r y .
Inputs

int o the d i s s o l v e d organic

phytoplankton secretion,
decomposition,
i n flo w.
enters

(Figure

the m a x i m u m c o n c e n t r a t i o n s w e r e

196 9 w h e n the t h e r m a l
culation

f r o m 6— 16 m g C 1 ^

phytoplankton

zooplankton secretions,

pool

included

autolysis,

benthic

an d a l l o c h t h o n o u s

Allochthonous dissolved organic material which
l a k e s is p r i m a r i l y h u m i c

aromatic

polyhydroxy carboxylic

in c o m p o s i t i o n .
acids

(fu lvi c

These

acids)

h a v e b e e n c l a s s i f i e d by s t r u c t u r e a nd by s o l u b i l i t y
bases
1966).
may

and acids
All

( C h r i st man ,

1964;

C h r i s t m a n and Ghessemi,

fractions absorb ultraviolet

fluoresce

(Buck,

1968;

in

light;

S i e b u r t h and J e n s e n ,

some
1968).

Ultraviolet absorption was quantitatively calibrated

in

Figure 24.

Isopleths of total dissolved organic carbon (mg C 1
, Duck Lake,
1968-1969. Sampling frequency was biweekly at 0, 1, and 3 meters.

TOTAL DISSOLVED ORGANIC
W

]
*

s

—
T

V

r \
10 9

DEPTH

CrrD

K>

i
f
1
B

> 1

r '

\\\

/
f
s

/j

O
f

9
/

,

*. 1 '1 . ?1
ll1
I
SEP OCT NOV DEC

..
JAN.

J Aytn
fc’L li

CARBON

N

/•••
! !
I
\ \ v
: 1
9 8
7 , 8 9 , ^
KJ/
8' 9
M
l
"
■ /
‘
'■ ' ! 1
! i
; •- r - v
„
i ,;
M
M » .
'
: i 1
'
,
i
!
■
li ■ i
i
. .
.i. i 1
i_ i II , . m
.i l.i
FEB MAR- APR MAY JUN. JUL AUG. SEP
\ J

J

113

o r g a n i c c a r b o n by s e v e r a l
in p r e p a r a t i o n ) :
(95% c o n f i d e n c e

complementing methods

1 2.7 m g C

1 ^/0D„C

i n t e r v a l — — 1.8)

(Miller,

in L awrence Lake

an d

13.1 m g C

1 ^/O D 250nm

in D u c k L a k e .
In t h e a n n u a l c y c l e
materials

o f t h e c o n c e n t r a t i o n of h u m i c

in Lawrence L a k e m o s t of the i n c r e a s e s w e r e

a s s o c i a t e d w i t h r a i n f a l l w h e n the l a k e w a s

stratified

(Figures

absorption^Qj^

varied

25,

26,

and

from 0.090 to

27).

The ultraviolet

0.200

(mean 0.136)

units w h i c h was

e q u i v a l e n t to a m a x i m u m c h a n g e of 2.5mg o r g a n i c
in a t o t a l d i s s o l v e d
over

the y e a r .

o r g a n i c pool w h i c h v a r i e d

and

27).

The

increase

period of rain depended
column,

the

8

mg C l

l a p s e of

in absorbance

(Fi gures
after

any given

after

the r a i n ,

and

Rainfall or snow m elt

the recent

and ultra­

violet absorption were clearly related o n February
13,

April

June

13,

November

26,

May
20

July

19, J u n e

3 1 —A u g u s t
9, J u l y

15 in 19
20,

6 8

Lake occurred

26,

, and on

a nd O c t o b e r

inputs

from the bottom

during the

(12m)

10—

of Lawrence

summer stagnation period when

b i o l o g i c a l o x i d a t i o n h a d u s e d all t h e o x y g e n ,
and

4,

in 196 9.

Humic

pH,

25,

u p o n the t u r b u l e n c e of the water

time

history of rainfall.

Ma y

1

During several weeks of heavy rainfall

ultraviolet absorption increased markedly
26,

carbon 1 ^

reduced redox potentials

(Figures

There w a s n e v e r a s u b s t a n t i a l humic

input

lowered

2 5a a n d b ) .
into Lawrence

Figure 25a.

Isopleths of ultraviolet absorption (250nm, 1cm) by dissolved
humic materials, Lawrence Lake, 1967-1970.

Figure 25b.

Isopleths of fluorescence (460nm, lOx scale units) in Lawrence
Lake from January, 1969, to May, 1970.

ULTRAVIOLET

TT

«UG SfP OCT NCW DEC

UC

AftSCMFTlON

SEI> OCT

Otc

J tH

fs*

115

FLUORESCENCE

460 nm

T T T T O J
t

i

:

/•
A

\

30 32

3640

i

V/'i
v
, ); '"-a

30

12S 36

\r

A

/

ij

A
10

11
12

A
I
's.1 w : i
i f a ll
■

JAN FEB

/ K 7 •^• 40'
-i ill - :__ ^ -TILi
34 36"

MAR. APR. MAY JUN. JUL. AUG SEP

'■

_ A-~\ ■
/"'A
U rV 26 V/' \

L / C,

OCT NOV DEC JAN

FEB

MAR

f
23

APR. MAY

Humic acid organic carbon per meter2 in Lawrence Lake (g C m’2).
The vertical arrows denote the major rainfall periods.

116

Figure 26.

HUMIC

CARBON

(A

LI T

m

Figure 27.

118

Weekly precipitation at Kellogg Biological Station, Kalamazoo
County, Michigan and deviations of the lake level from the
annual mean, 1967-1970.

cm

PRECIPITATION

~h, rl Il.ir.
LAKE

L AWRENCE

LEVEL

LAKE

DUCK

LAKE

-10

NOV DEC
1967

JAN

FEB MAR APR MAV JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOv DEC JAN
1966
-I1969
-I-

FEB MAR APR
'970

may

120
L a k e by t h i s m e a n s b e c a u s e o n l y a s m a l l v o l u m e of w a t e r
between

10-12m was effected.

was more

Humic

f r o m 0 . 1 4 2 — 0.627 w i t h

(Figure 28).
of

l- 1 ; the t o t a l

pool varied by
absorption

fa ce w a t e r s d i d

and winter

reflect

(Figures

seepage

the w a t e r

level

ta b l e ;

humic materials

tended

to a c c u m u l a t e d u r i n g

Lawrence Lake
both

tuated more

level

and

p a t t e r n of

in s u r ­

increase
Lake

is a

surface waters

t he s u m m e r

period.

leave

In

t h r o u g h the

humic c o n c e n t r a t i o n

fluc­

t h a n in D u c k L a k e .
carbon concentration

c o n c e n t r a t i o n i n D u c k L ake g a v e

s i m i l a r to t h e a n n u a l c y c l e
29).

absorption

absorption

During

is s t a b i l i z e d by the w a t e r

surface d r a i n a g e could
lake

anaerobic decom­

Because Duck

entering with

S u b t racting humic
to t a l D O C

29).

the r e l e a s e

stratification.

the general
27,

carbon

The m a x i m u m

associated w i t h

from the bottom by

with rainfall

and

to a m a x i m u m c h a n g e

stratification the u l t raviolet

lake,

0.200 units

dissolved organic

in D u c k Lak e w a s

p o s i t i o n d u r i n g summer

(Figure

a mean of

humic materials

10 mg C 1 ^ o v e r the y e a r .

of dissolved material

outlet;

250nm b y

This was equivalent

6.25 m g C

summer

f r o m the b o t t o m

i m p o r t a n t in s h a l l o w e r D u c k L a k e .

In D u c k L a k e a b s o r b a n c e
ranged

input

of d i s s o l v e d

from the

a pattern
humic materials

The simple c o rrelation b e t w e e n humic

a n d t otal D O C a t

for a l l d e p t h s and d a t e s

lm w a s r =

0.73

(p - 0.95);

o n log t r a n s f o r m e d d a t a

Figure 28.

Isopleths of ultraviolet absorption (250nm. 1cm) by humic materials
(upper) and relative fluorescence (360nm 1 filter) in fluorometer
units X 10 in Duck Lake, 1968-1969,
121

ULTRAVIOLET
ABSORPTION
-n r ■n— r— r'— ’
—

DEPTH

Cm)

390 300

220

205

1

-250 \
-300

-/
170:200

.170

2

\
\

300
.«0
!

J65.18 220.300

-300220,v

-AOO ,
i

500
.600

,40 I

400

3

.400

4

ill li ■ : I
OCT

NOV

DEC

JAN

FEB

MAR

APR

MAY

JUN

JUL

FLUORESCENCE

AUG

SEP

460 nm

DEPTH

(mj

0

44
40/

2

4
OCT

NOV

DEC

JAN

FEB

MAR

APR

MAY

JUN

JUL

AUG

SEP

123

Figure

29.

2
Humic acid o r g a n i c carbon per m e t e r
(g C m - 2 ) (-), t o t a l d i s s o l v e d o r g a n i c
c a r b o n (g C m “ 2 ) (-- ■ --- ) a n d t h e d i f ­
f e r e n c e b e t w e e n t h o s e two, r e p r e s e n t i n g
t h e m a x i m u m D O C of a u t o c h t h o n o u s o r i g i n
(
E3
) » Duck Lake .

DISSOLVED

m » -h »

£
>

.

S

ORGANIC

CARBON

( gm t i ' 1 )

“ w u I C I 5 n » * 8

—

K t

124

-

o

T

L
L-

5

--

*-

°
O
*

V

c
#
i *

4-

■!-"""
*
\

*

*

*

1

i3

^
O

-

((.w

U

ulO)

U

4

3

. !
^

oao

O

N

OlHDH

9

4

1 25
r = 0.57

(p —

released

from the bottom,

calibration
non U.V.

0.95).

B e c a u s e m o s t h u m i c m a t e r i a l wa s

f a c t o r was t o o

19 d i d

causal

being released
22,

June

in a d d i t i o n
25,

and

production mask

the apparent

relation between DOC

and ultraviolet

absorption

29).

was c o r r e l a t e d w i t h the
duction

(r =

materials

0. 391),

>

where

organic

logs of

(r - 0 . 5 4 1 ) ,

and

The

level

(stepwise multiple

log

light

secretion +
duction +
.0089,

+

.059

.351

light

.304

(r = 0. 3 6 7 ) ,

algal

temperature

with production.
m a t e d by

log d i s s o l v e d

temperature

(r = 0.295),

(P - 0.95)

partial

large q u a n t i t i e s of

Only on May

In L a w r e n c e L ake

+

carbon

high planktonic

(Figure

.0825

the o r g a n i c

s m a l l or

absorbing carbon were

to the h u m i c m a t e r i a l s .
July

either

secretion

and

regression):

log c o n d u c t i v i t y

production,
explained
(F = 11.9,

c e l l v olu m e ,
alkalinity,

—

*0^7

only

.035 l o g o x y g e n c o n e .

D O C in L a w r e n c e

conductivity,

in DO C.

9 5 ( 9

Lake was

1 2 8

) =

T he

temperature,

algal

humic materials

45.5% of th e v a r i a t i o n

critical F

log

.04 3 log p r i m a r y p r o ­

the variation

and

correlated

log DOC =

c o r r e l a t i o n c o e f f i c i e n t s o f light,

cell n u m b e r ,

humic

of D O C c o u l d b e s t be e s t i ­

log h u m i c O D 250 +

36% o f

pro­

(r = 0.222)

light w e r e

log t e m p e r a t u r e -

explaining

carbon

secretion,

maximally

in D O C

in 1968

Significantly,

primarily associated with fac­

to rs of p r i m a r y p r o d u c t i o n

and

its c o —c o r r e l a n t s .

126

The

total dissolved

bake showed
all data)

simple correlations

w i t h humic

primary production
particulate
0. 410 ),
It w a s

organic

cell

0.471),

carbon

volume

temperature

(r = 0 . 4 1 2 ) ,

(r = 0.377),

and

(r = 0.572),
(r =

li g h t

(r =

bacterial morphotype

— 0.4 51) .

partial

production,
F

9 5 ( 3

5 3

an d b a c t e r i a l

j =

2.79)

of t h e v a r i a t i o n
predicted
0.032

added

number

That

=

In D u c k L a k e

(F —

14.9,

0.296

log h u m i c

allochthonous

and

determining

total

Lake

T h e r e w as

a time

formation of
correlation
sidered,

DOC,

organic products

46%

levels

absorption +
numbers

nonplanktonic
important

(Fi gur e 29) .

in

In

all of its c o —

s t r o n g l y correlated with DOC.

lag b e t w e e n p r i m a r y p r o d u c t i o n a n d
which reduced

in b o t h

s u c h as

been major

DOC

primary p r o d u c t i o n and

correlants w e r e most

critical

log b a c t e r i a l

m a t e r i a l s w e r e the m o s t

Lawrence

humics,

fit c o u l d h a v e b e e n

i n p u t s of h u m i c
the

(r =

correlation of

lo g p r i m a r y p r o d u c t i o n - 0 . 0 3 8

+ 1. 1 2 7 .

0.3 3 2 ) .

s i g n i f i c a n t l y to e x p l a i n

in D O C .

f r o m log D OC

(r =

(r = — 0.535)

and a large m o t i l e c o c c o i d
15 v a r i a b l e s ,

0. 4 6 5 ) ,

secretion

negatively correlated with calcium

Of

in Duck

(log t r a n s f o r m a t i o n of

compounds concentration

(r =

organic

c a r b o n le v e l

lakes.

secretion
of b e n t h i c

contributors

t he

Other

strength of

s o u r c e s of D O C

that
not con­

f r o m a q u a t i c m a c r o p h y t e s or
decomposition,

could have

to the d i s s o l v e d o r g a n i c

pool.

127
The

strong c o r r e l a t i o n w i t h hum i c material

indicated

that

Annual

inp uts

f r o m t h e b e n t h o s ar e

calculated

carbon—equivalency

added

by a

carbon-equivalency

fo r the u l t r a v i o l e t

absorbing organics

v a l u e s of t h a t

factor.

sampling dates

The

Lawrence Lake was

12.7 m g C / O D 250*

factor

streams

(F =

However,

the m i n i m u m

27.6 m g C 1 ^ / O D ^ ^ q

indicated that

at all

in

times,

^ crn)
at l e a s t

t w i c e as m u c h o r g a n i c c a r b o n a c t u a l l y e n t e r e d

the

as w a s c o n t a i n e d

in the h u m i c m a t e r i a l

(Miller,

in p r e p a r a t i o n ) .

A m i n i m u m b u d g e t of

dissolved

carbon was determined w i t h

factor.

organic
In D u c k

a m o u n t of o r g a n i c
materials

o d

only could

carbon

came

the

latter
the

in w i t h t h e h u m i c
of a q u a t i c

be estimated

estimated

angiosperms.

(13.1 m g

i n p u t of d i s s o l v e d

to L a w r e n c e L ake w a s

and only

8.1 g C m ^ yr

fo ld d i f f e r e n c e s u g g e s t s
input o f dissolved,

swamp and t h e
did

allochthonous

organic

2 5 0 ).
Minimal

th e

that

itself

lake

no w a y t o e s t i m a t e

in b e n t h i c d e c o m p o s i t i o n

A humic b u d g e t
C/

Lak e t h e r e w a s
carbon

to

by m u l t i p l y i n g the d i f f e r e n c e

b e t w e e n O D 2 5 0 n m o n c o n s e c u t iv e

from inlet

important.

budgets of d i s s o l v e d humic c a r b o n

the l a k e s w e r e

factor used

in D u c k L a k e

not v a r y

32 g C m

^ in 1 9 6 9

yr

(Table

that complex

—1

cm yr

for

12).

factors

h u m i c — like materials

lak e b o t t o m f r o m y e a r
(105 vs 108

—2

organic

to y e a r .

1968
Th e

four­

affect
f r o m the
Rainfall

^ ) significantly between

TABLE 12.

Humic carbon budgets for Lawrence and Duck Lakes.

1968

1969

Lawrence Lake:
Total carbon
input/lake

1596.7 kg lake

Humic carbon
input/lake

- 1

yr

732.0

Total carbon
input m“2

32,16 g C m

Humic carbon
input m-2

14 .74

- 1

403.7 kg lake

- 1

yr

185.1

_*
yr”

_o
_i
8.13 g C m ” yr”

3.73

Duck Lake:
Total humic carbon input/lake
Humic carbon input m

-2

1040.97 kg
8,25 g m

lake ^ yr ^

-2

yr

-1

129
19 68 a n d

1969,

the w i n t e r

a l t h o u g h the w a t e r table

1 9 6 8 — 69

Lawrence Lake was
vented

(Figure
saturated

the a e r o b i c

incomplete

then released
to b i w e e k l y

The m a r s h

in 1969,

formation of humic

lignins and phenolics.
from

27).

In

spring turnover,

f r o m th e b o t t o m .

in

19 69

(Figure

humic

carbon m

(199 d a y s
t i m e of

—2

day)

total).

500 d a y s

of humic

acids

low

the r u n o f f

organic materials

The change
lowered

the accuracy

in L a w r e n c e L a k e
slow

d u r i n g periods of no r a i n

(Figure

for the m e a n

26).

influx.

However,

when water

have

that CaC O ^ does

seawater because CaCO^
by a n o r g a n i c

rapidly

Particles of CaCO^

s o m e DOC.

Chave

coating;

the

season

(Wetzel

Suess

and

inacti­

a d d i t i o n of

C a C l ^ or N a H C O ^ c a u s e s r a p i d p r e c i p i t a t i o n of C a C O ^
organic
water

material.

flowing

th at c a u s e

T he C a C O ^

into Lawrence

(1970)

in n o r m a l

are p r o t e c t e d
however,

just

and adsorbed

and

not precipitate

nuclei

in 1969

standing crop

s e t t l e d u r i n g the g r o w i n g
removing

(19.3 m g

for a r e p l a c e m e n t

standing crop dropped

1971)

vated

from weekly

in O D ^ ^ q , w a s v e r y

and A l l e n ,
shown

resulted

25).

(1.4 years)

(1968),

from plant

and m o r e c a r b o n was

This w o u l d account

compounds

level w a s
after

by d e c r e a s e

around

which perhaps pre­

D e c o m p o s i t i o n of h u m i c m a t e r i a l s
as m e a s u r e d

30cm during

soi l

1968 e a r l y a n o x i a

sampling may have also

of e s t i m a t e s

rose

in the s u p e r s a t u r a t e d

an d
stream

L a k e m a y a c t a s t h e n uc l e i

pr e c i p i t a t i o n of more CaCO^ w h i c h adsorbs

130
humic
them

compounds,

effectively removing

f r o m so lut i o n .
The

Lake

among others,

total

in 196

duction,
rates

8

input of organic

w as

60% of t h e p l a n k t o n i c

but only

the

carbon

15%

in 1969

(Table

s t a n d i n g c r o p of h u m i c

t w o ye ars.

Thus

the humic

t h e w a t e r s h e d of s m a l l

lakes

p o r t i o n of the a n n u a l o r g a n i c

primary pro­

12).

At

compounds

ated organic carbon were replaced
every

i nto L a w r e n c e

these

and a s s o c i ­

by the annual
acid

influx

introduction

can r e p r e s e n t

from

a sizable

c a r b o n a c c r u i n g to t h e

open water.
primarily
yr

In D u c k L a k e h u m i c c o m p o u n d s w e r e r e l e a s e d
-2
by a n a e r o b i c b e n t h i c d e c o m p o s i t i o n (8.25 g m

and were

of humic carbon
In 1 969
absorbing
annual

sufficient
in less
the

to r e p l a c e

the standing crop

than one year.

influx organic

humic compounds

c a r b o n in u l t r a v i o l e t -

equalled

7.5

and

p l a n k t o n i c p r o d u c t i o n in L a w r e n c e

respectively.
important
the d e e p e r
were more

The

inputs

in D u c k Lake,

column.

lakes,

f r o m the b o t t o m w e r e m o r e

inputs

In

f r o m the w a t e r s h e d

T h e p o t e n t i a l m e t a b o l i s m of

heterotrophs on that carbon source was
the m e a n d a i l y p r i m a r y

and D u c k

the

the s h a l l o w s e e p a g e lake.

Lawrence Lake,
important.

16% of

production

about

15% of

for the entire w a t e r

131
I.
The most
variations

Planktonic

significant

in DOC

level

factors that contributed

in L a w r e n c e L a k e w e r e

related w i t h primary production of
of o r g a n i c
occur via

carbon

to

The

47% of t h e

before

it

and

(3)

Transfer

sediment

epilimnetic

rapidly

(2 ) d e a t h or

bacterial d e g r a d a t i o n of

trap analysis

showed

t h a t 2 5%

particulate material was

s e t t l e d b e l o w 5m.

autolyzed

all c o r ­

the plankton.

(1 ) s e c r e t i o n d u r i n g g r o w t h ,

cells.

to

f r o m t h e a l g a l c e l l s to t h e w a t e r m a y

autolysis of cells,
dead

Sources of DOC

Probably

lost

the d y i n g cells

and w e r e s u b s e q u e n t l y d e c o m p o s e d by

bacteria.
Duursma
DOC

(19 63)

in t h e N o r t h Sea,

primary production
planktonic
only

6

dried

2.6 g m

—3

(55-75 g C m

release of DOC

that the net c h a n g e of
yr
—2

—1
yr

was equal
— 1

sustain the b a c t e r i a l

Scenedesinus

organic

carbon

initial

loss w a s

soluble compounds

first
the

int o

stimulus
after

1:40,

source

fou r d a y s

alone
Freezetheir

immediate autolysis of water

the d i s s o l v e d

homogenized

at 4 0°C

to

( O t s u k i , 1968).

phase where heteroIn s e w a g e s l u d g e

cells provided

for a rapid o x y g e n c o n s u m p t i o n w h i c h

500 m i n u t e s

phyto-

equal

l o s t 40% o f

trophic d e c o m p o s i t i o n was v e r y rapid.
waste diluted

Because

respiration.

s p . in m i c r o c o s m s

in t h e

}.

to the

in L a w r e n c e L a k e w a s

% of t h e p r i m a r y p r o d u c t i o n t h i s

could not

Th e

estimated

(Varma and D i G i a n a ,

t he
stabilized
1968).

132
Thus

the

present
lost

substrates
in a l g a l

for e n h a n c e d

cells.

phosphates
organic

autolysis

( G o l t e rma n,

nitrogen m o r e

four d a y s ) .

1964).

of c e l l s

nutrient

release by hydrolysis

material

rapid and

cells

proportionately much

late carbon
15%

the

from

in t h e

limiting

the organic
tha t t h e

compounds.

loss o f o r g a n i c

The

loss o f p a r t i c u ­
(Melosira)

from H a e m a t o c o c c u s , 33%.

rapid than

the c o n c l u s i o n was

q u i c k l y autolysed

to

the oxygen upta k e by

f i r s t two d a y s .

the r e l e a s e w a s m o r e

intra­

in a e r o b i c d e c o m p o s i t i o n was

larger t h a n

and

first

the a c t i o n o f

not rate
of

lost

the diatom d o m i n a t e d plankton

in 24 hrs,

response,

20- 30%

by

demonstrated

fr om k i l l e d

bacteria during

hydrolysis of organic

(only

enzymes

(1964)

are

in a f e w h o u r s

U V —killed cells

cellular

Krause

is

and

sl o w l y

Autolysis

activity

Unruptured UV— irradiated cells

50% of t h e i r c e l l u l a r p h o s p h o r u s

b e c a u s e of a r a p i d

was

bacterial

the heterotrophic

that

the cell a n d

Since

intracellular

enzymes

released dissolved organic

carbon.

killed

Autolytic

l o s s of c e l l m a t e r i a l

algae w a s

1 0

( G o l t erm an,

1968) .

c a r b o n occurred
added.

0

% of the d r y weight

No f u r t h e r

in th e nex t

1 0

in d r y w e i g h t

autolytic

in j u s t d a y s

r e d u c t i o n of p a r t i c u l a t e
days

The a d d i t i o n of P s e u d o m o n a s

a c c l i m a t e d to a l g a l
loss

-2

from sterile

until

bacteria were

s p . which had been

materials caused

from c h l o r o f o r m killed

6 0 — 70%

Scenedesmus

133
in the

next

30 days,

a t w h i c h t i m e the b a c t e r i a l

al so w e r e d e c r e a s i n g .

The

fraction of organic

lost by w e i g h t was d e p e n d e n t u p o n the
plankter
latter

and

species

its p h y s i o l o g i c a l c o n d i t i o n

state determined

the

c o n t e n t of

Thus

releases

the

autolysis

is

DOC

in m i c r o c o s m s ,

the n 7% of

r e m a i n as r e s i d u a l DOC.
POC

2.4 g C m

resistant

to

released
7% of t h e

(1968)

-2

yr

-1

or

found

the total
Since

P OC

evidence

produced

mg C m

—2

from the

34.2
day

cell

—1

—

2

literature

indi­

and

that

in to d i s s o l v e d

to b a c t e r i a l

Si n c e

as o r g a n i c

was

secreted

not m e a s u r e d

immediately during photosynthesis,
as a n i n c r e a s e

in ce ll c a r b o n .

plankton standing crop w e r e unchanging,

,

is r a p i d l y

is c o n v e r t e d

production

-1

of D O C

organic compounds which are refractory
5 . 7 — 8% of the p r i m a r y

yr

produced.

t h e cel l c a r b o n

carbon

pro—

g C m

labile d i s s o l v e d organic m a t e r i a l s

initial

should

the p h y t o p l a n k t o n

stratum was
6 . 6

in

for Scenedesinus

further o x i d a t i o n would be

f r o m 10 -3 0% o f

as

carbon

formation of biologically

in the 0 - 5 m

In c o n c l u s i o n ,
cates that

organic

f rom c e l l u l a r d e c o m p o s i o n o c c u r r e d
as O t s u k i

about

t he c e l l c o n ­

in the e p i l i m n i o n .

L a w r e n c e La k e ,

d u c t i o n of

The

the m e chanism w h ich undoubtedly

If t h e sa me r a t e o f
refractory

of p h y t o -

at d e a t h .

l a r g e s t a m o u n t of d i s s o l v e d

i nto t he w a t e r

carbon

intracellular

e n z y m e s p o t e n t i a l l y a v a i l a b l e to d i g e s t
tents.

numbers

th e

a tta ck.

carbon

it w a s

If the
fl ux of

134
organic carbon transferred through
m a y be e q u a l

to 23-4 5% of

production.

Thus,

DOC

the d i s s o l v e d p h a s e

the n e t p a r t i c u l a t e p r i m a r y

levels

in L a w r e n c e L a k e c o r ­

r e l a t e d b e t t e r w i t h p r i m a r y p r o d u c t i o n t h a n in D u c k L a k e
where benthic metabolism was quantitatively more
as a s o u r c e of DOC.
the p a r t i c u l a t e

important

A d d i t i o n a l l y , t h e lo ss of 2 3 - 4 3 %

production

to t h e

dissolved phase

w i t h th e r a n g e of p e r c e n t a g e w e i g h t

of

agrees

loss o f D O C s e t t l i n g

ou t of t h e e p i l i m n i o n .
J.
If
subsystem
organic

H e t e r o t r o p h i c U p t a k e of L a b i l e
Organic Compounds

the h e t e r o t r o p h i c m e t a b o l i s m
is c l o s e l y

carbon,

linked

to t h e

p r o d u c t i o n of d i s s o l v e d

then phytoplanktonic

molecular weight

sugars and o r g a n i c

synthesis

should

correlate with

bacterial

a s s i m i l a t i o n of t h o s e

in the p l a n k t o n i c

s e c r e t i o n of

acids during p h o t o ­

independent assays
substrates.

(Wright a n d H o b b i e , 1966)

Figures

c o r r e l a t e d w i t h p r o d u c t i o n an d

secretion rates
The
glucose

31)

to s u p p o r t

t his

theoretical maximum

(v m a x )

both

in p a t t e r n o f h i g h and

l a k e s at

31).

Both corre l a t e d

production,

secretion,

(Table

13,

(Table 14).

r a t e s of u t i l i z a t i o n
lm exhibited

of

similarity

low v a l u e s w i t h m a x i m a o c c u r r i n g

in l a t e A u g u s t - e a r l y S e p t e m b e r
and

hypothesis

f or

Substrate

dilution bioassays
30 and

small

and

in b o t h y e a r s

(Figures

significantly with primary
the c o —c o r r e l a t e s o f

30

TABLE 13.

Comparison of kinetic bioassay parameters in Lawrence and Duck Lakes.

Duck Lake

Lawrence Lake
mean

range

mean

range

Glucose (Annual)
Vmax (ug C 1 ^ hr
Kt + Sn (ug C 1“1)
Tt (hours)

0,042
2.72
73.0

0.005-0.18
0.15-7.80
17-300

0.143
2.72
19.0

0.04-0.49
0.04-8.40
6-50

0,193
3.93
35.0

0.017-0.66
0.22-7.30
1.7-117

2,06
43.04
16.0

0.24-5.80
2.1-247.0
4.4-43.0

0.075-1,41
2.20-89.4
20-309

1.81
76.39
44.0

0.54-2.84
30.142
34-58

Acetate (Mar.-Sept.)
Vmax (ug C 1"^* hr-*
Kt + Sn (ug C l"1)
Tt (hours)

Glycolate (May-Sept.)
Vmax (ug C 1"! hr"*-)

Kt + Sn (ug C 1“1)
Tt (hours)

0.63
47.65
99,0

Figure 30,

Changes in uptake velocity (Vmax), substrate concentration
(Kt + Sn) and turnover time (Tt) of glucose, acetate, and
glycolate in Lawrence Lake at 1m, 1968-1969,
136

LAWRENCE

LAKE

1m

O

?
4
f
>

o

?
137

MJQ I0 »

OCT

NOV

JUN

Figure 31.

Changes in uptake velocity (Vmax), maximum substrate concentration
(Kt + Sn) and turnover time (Tt) of glucose, acetate, and glycolate
in Duck Lake at lm, 1968-1969.

a1
r

*4

t
r

01

jI

l!O •I
M*

139

I
I

3

m

xt now mc

m

TABLE

14,

Multiple regression-p*rtial

correlation analysts of substrate u t i l n a t i o n

for glucose,

acetate,

and glycalate.

Partial correlation of
r‘

F found

Critical

variables

F

m

Simple

order

linear correlations

(significant P > 0.95)

of significance

? ^ i-95

Lawrence L a k e :
I.

Glucose

c7*

14, It

2,39

T e m p e r a t u r e , secretion,

(df 2,29!

h u m i c s . light,

oxygen

Produc t i o n

1.740),

temp.

(.630)

Acetate

964

Hurics,

c . 29
Jf - 4 ■

glucose

-secret ion,

light,

temperature
Glycolate

994

55.41

6.79
■'d f " 4

1

(-.470)

Humics

1.943),

i ,735), DOC

(-.625)

Temp.

I . 6 2 0 , light

production

(.994)

(.779), p r o d u c t i o n

secretion,
alkalinity,

temp.

gluclose v n

T e m p e r a t u r e , DOC , I i g h t ,
humics

1.587), a l k a ­

linity

(.839), p r o d u c t i o n
! .609) , secretion

(.587) , humics

(.583)

Duck L a k e :

1.

Glucose

954

: 3. -c

Temperature,
(df,

r,17)

dark secretion,

.

Acetate

994

23.44

production

cell number,

344

14.13

(.579),

(.563) , secretion

19.4

-Secretion,

{df 12,2]

bacterial

pH,

-DOC,

numbers,

9.28

Temperature,

,'df 3,31

numbers,

POC,

cell volume,

light production,

Slycolate

dark fixation

dark fixation,

temperature,

3.

(.753),

(.684), dark secretion

pH

2

Temp.

alkalinity, production,

(.492)

None,

df 11

.553,

secretion

number

;.555),

critical r

(-.505),

S

(-.517) , cell
humics

1.359)

cell number

bacterial

-oxygen

light

{.6Cl!,

cell volume

None,
oxygen

df 5 critical
(-.691),

temperature

r • .754

humics

(.608)

(.645)

140

3,

I-,6471,

s ecretion

1 .61’ ), light

I.

humics

{.667), conduc t i v i t y

141

production
was

(Table 14).

related m o r e

dissolved

to h u m i c o r g a n i c

organic

D u c k Lake.

and

secretion
lakes.

showed maxima

in A p r i l ,

Acetate V

with dissolved
and

in J u n e a n d J u l y i n

J u n e —J u l y ,

unlike glucose,

factors

carbon

for u p t a k e

were not related directly

Wright and Hobbie

(1966)

utilizing heterotrophs
t o be p h y s i c a l l y

and H o b b i e

(and n o t

attached

in bo t h

to

(1967)

secretion.

found

filterable

In D u c k Lake

the

acetate V_
with particulate
max

particu­
partial

organic

significant.

the same dates,

in m i d - s u m m e r .

except

Glycolate V„
max

that

to g l u c o s e u p t a k e .

temperature,
of

heterotrophic
under

similar

too small

the

(NS),
humics,

A l though the number

to d r a w c o n c l u s i o n s ,

u p t a k e of g l y c o l a t e

showed

(NS), light

and p o s i t i v e c o r r e l a t i o n s w i t h

the c o n t r o l of

occurred

In D u c k L a k e g l y c o l a t e V _
max

and bacterial numbers.

samplings was

two

in L a w r e n c e L a k e c o r r e l a t e d

negative correlations with secretion
( N S ),

the

the m a x i m a

w i t h p r o d u c t i o n - s e c r e t i o n an d h u m i c m a t e r i a l s ,

and oxygen

acetate

heterotrophs)

Glycolate v max showed no pattern bet w e e n
lakes on

in

of acetate,

the g l u c o s e

to l a r g e r

in L a k e E r k e n .

correlation of

and S e p t e m b e r

humic m a t erials and negatively w i t h
total d i ssol ved o r g a n i c

late material

to total

correl ated very s ignif icantl y

max

The controlling

carbon was

carbon than

max

carbon.

A
cetate V_
-------max
Lawrence Lake

In L a w r e n c e L a k e g l u c o s e V

the

in D u c k L a k e m a y be

non-planktonic system

lik e a c e t a t e .

142

In L a w r e n c e L a k e in t h e
of

iri s i t u

an d

31)

substrate concentration,

increased before

(V
).
max

s p r i n g the m a x i m a l
Kt + Sn

the b a c t e r i a l

T h e m a x i m u m Kt + S n o b s e r v e d

with

temperature,

is e v e n s t r o n g e r

for g l u c o s e

196 9a)

and

that

this physical

than regulation by

species

of

of bacteria

occurred

velocities
control

substrate

the y e a r w h e n

30

Annual cycle data

o f all s u b s t r a t e - u p t a k e

suggest

bility during parts

( Fig u r e s

uptake potential

in t h e a u t u m n w h e n V _
max was decreasing.
and high correlations

estimate

availa­

temperature

are changing

{Allen,

{Daubner,

1969) .
The estimates
for g l u c o s e
glycolate
acetate

acetate were

(Table

13).

The

in b o t h

times

Lake

turnover time
(faster)

the s a m e ,

The
production,
glucose-C,

less t h a n
the

fo r

levels

10-20%

(Table

13).

in D u c k

of b o t h

greater

f o r all

Figures

levels of

than

However,

8 times

Lake than

the

same

substrates

30 a n d

in

time

to 5 0%
than

higher

or
less

in L a w r e n c e

31).

heterotrophic

were m u c h higher
10.6 X

1

The replacement

in s i t u wa s a b o u t

13,

8 ug C

of a c e t a t e w e r e

2 times higher

in D u c k L a k e

(Table

c a r b o n 1 ^)

e s t i m a t e of m a x i m u m c o n c e n t r a t i o n o f g l u ­
lakes wa s

glycolate

Lawrence

Lake

10

In D u c k L a k e ,

th e m e a n c o n c e n t r a t i o n s
and

(mg o r g a n i c

and g l y c o l a t e carbon w e r e

glucose.
cose

and

o f Kt + S n

activity

in D u c k L a k e

for a c e t a t e - C , and

( Vm,a„x) , like

(3.4 X fo r

2.6 X f or g l y c o l a t e - C )

143
t h a n in L a w r e n c e Lake.

Glycollate-C occurred

h i g h e s t c o n c e n t r a t i o n of a l l thre e s u b s t r a t e s
Wright

11970]

found).

Allen
cose

(as

G l u c o s e and a c e t a t e Kt + Sn

in L a w r e n c e L a k e w e r e s i m i l a r to t h o s e
(1967,

in the

found by W e t z e l

1968)

in two n e a r b y

I nd i a n a m a r l

(1969)

found acetate

Kt + Sn m u c h h i g h e r th an g l u ­

in L a k e L o t s j o n

(max.

d e p t h 2.5m)

lakes

(14m deep).

b e c a u s e of an

a p p a r e n t r e l e a s e of a c e t a t e

f r o m the b o t t o m o f the pond.

The

is o bvious.

s i m i l a r i t y t o Duck L a k e

W h e n t h e h e t e r o t r o p h i c up t a k e r a t e o f a c o n s t a n t
14
low concentration glucose-C
w a s p l o t t e d (v = g l u c o s e - C
u p t a k e jjg C

1 ^ hour ^) o v e r

heterotrophic
had

levels b y m i d - A p r i l

the biomass dependent V

r e a c h summer

t he v e l o c i t y o f

u p t a k e of low c o n c e n t r a t i o n s o f

rea ched s u m m e r

Apparently

the year,

levels until June,

instantaneous

ni3x

substrate

(Figure 32).

, w h i c h did not

did n ot e f f e c t the

uptake significantly.

The m u l t i p l e r e g r e s s i o n - p a r t i a l c o r r e l a t i o n
analysis indicated
secretion may

that p r i m a r y p r o d u c t i o n a nd o r g a n i c

be the s ou r c e

of substrates controlling

a portion of

t he p l a n k t o n i c b a c t e r i a l h e t e r o t r o p h y

(Table 14).

The validity of

depended upon
b i o a s s a y for V

(a)
max

this t e n t a t i v e c o n c l u s i o n

the t i m e c o u r s e i n d e p e n d e n c e of the
and

(b)

t h e a b i l i t y to r e s o l v e c a u s e

a n d effect r e l a t i o n s h i p s d u r i n g d i u r n a l c y c l e and
o v e r a w e e k l y period.

(c)

T h e b i o a s s a y of W r i g h t and H o b b i e

Figure 32.

14
-1
-1
Heterotrophic uptake rate of
C glucose carbon (pg C l
hr )
at 1.7-1.8 and 0.75-0.80pg C 1”! from May, 1968, to August, 1969.
144

LAWRENCE

L

Im

80
60
40
v-

G LU CO SE

C

20

to
8

6
4
A:.75-.8Qug Glucose C

2

0
MAY JUN

JUL.

AUG SEP

OCT

NOV

D€C

JAN.

FEB.

MAR. APR

MAY

JUN.

JUL.

AUG

146
(1965)

has

problems

been shown

to h a v e c e r t a i n m e t h o d o l o g i c a l

(H ami l t o n e t a l .,

1966)-

If u n i f o r m l y

in t h i s

st u d y ,

labelled

the m o s t

d a t i o n of assimilated

showed

occurred
Thus,
too

low,

between

lakes

on

25,

Calculated V max *

(F igu re
levels

12).
between

synthetic

1969,

max

at

0845-1530

fixation and

u p t a k e of

lm i n D u c k L a k e s h o w e d

occurred

hrs.

1 ^ hr

22 °C — 0 . 5 ° C

between

845— 1200

T h e e s t i m a t e of Kt + S n r e m a i n e d

p a t t e r n of Kt + Sn,
Thus

9,

yg G l u c o s e - C

p a t t e r n of hetero t r o p h i c

1969,

m a x i m u m e s t i m a t e of V

incubations.

the s a m e d a y .

September

The diurnal

in c a l c u l a t e d v„
max

directly comparable

0.207
0.149
0.110
0.012

glucose on April

1S miniIIl^ zed

f o r v m a x roay be 25%

T i m e F r o m t_
o

D u c k L ake ,

c °2'

three-hour

nonetheless,

1 .00 hr
3 . 50
6 . 43
10.25

(b)

14

to

summer data

b u t t hey are,
the t wo

C

(28%)

a sizable reduction

experimental

Cumulative

14

namely the oxi-

d e t e r m i n a t i o n of u p t a k e k i n e t i c s

be t w e e n o n e - h o u r and

the

error,

a r e u s e d as

1969).

A time c o u r s e

that

V a c c a r o a nd J a n n a s c h ,

substrates

serious

organic

(Hobbie a n d C r a w f o r d ,
(a)

1966;

The

hrs

at high

p a t t e r n of p h o t o ­

secretion also

highest between

a

l o o k e d l i k e th e

0 8 4 5 — 1530 hrs.

t h e p a t t e r n of h e t e r o t r o p h i c m e t a b o l i s m o f g l u c o s e

^

147
in s i t u w a s c l o s e l y l i n k e d
duction.
time

S a u n d e r s and S t o r c h

lag b e t w e e n

Potter

(1

9 6 4

) had

(unpublished data)
for

in Frains

(1971)

observed

s e c r e t i o n an d b a c t e r i a l
observed

b acterial n u m b e r s over

changes

to secretion and p r i m a r y p r o ­

in

S t o r c h and S a u n d e r s

investigated cumulative pool

secretory compounds using

Lake,

assimilation.

short-term fluctuations

24 h o u r s .

have

a slight

Michigan.

similar

size

techniques

They observed maximum accumu­

l a t i o n of s e c r e t o r y products

a b o u t two h o u r s

after s un­

s e t w i t h s u b s e q u e n t u t i l i z a t i o n d u r i n g the night.
(c)

Daily

variation

heterotrophic

u p t a k e of g l u c o s e

mined between

1200-1400 hrs

8— 13 S e p t e m b e r ,
ture

1969,

at l m

The

(Figure

and glucose

(r =

0. 762 ,

33).

Water

this

algal

significant over

Thus,

from

tempera­

significantly over

was

P = 0. 9 5 ) .

and

in D u c k b a k e w a s d e t e r ­

simple linear correlation between

photosynthesis
six days

production

f o r six c o n s e c u t i v e d a y s

and w e a t h e r d i d not c h a n g e

interval.

in primary

the

synchronization

of p r i m a r y p r o d u c t i o n a n d b a c t e r i a l h e t e r o t r o p h y b y
extracellular

secretion during photosynthesis

to b e s u b s t a n t i a t e d o n a d a i l y ,

weekly,

and

seems

seasonal

basis.
K.

T u r n o v e r of the S e c r e t o r y
of O r g a n i c S u b s t r a t e s

The d y n a m i c s of th e
photosynthetic

products

Pool

secretory pool of algal

in D u c k b a k e w a t e r w a s d e t e r m i n e d

148

Figure

33.

Primary production, glucose heterotrophic
u p t a k e (Vm a x ) , a n d i n s o l a t i o n (cal c m - 2 d a y ” 1)
d e t e r m i n e d in s h o r t - t e r m s m a l l b o t t l e i n c u ­
b a t i o n s u s i n g w a t e r t a k e n f r o m t h e la ke at
lm o n t h a t d a y (------- ) a n d f r o m a 20 1
c a r b o y p l a c e d in the l a k e o n S e p t e m b e r 9,
1969 (
).

149

ro

DUCK

500

&

£

CD

1m

L

400

300

in situ

120

100

00

>

Q ■§
Or
cr

60

C arboy

o
>- 5"4 0
0C
<

20

cr
cl

'T-

t_rn

.5

L±J^,4
O

3 .3

y

| .2

O > .1
8 SEP

9 S E P 1 0 S E P 11-SEP 12 S E P 13 S E P

IV

150
by m i x i n g
14

the m i c r o f l o r a w i t h

C-labelled

organic

lake w a t e r c o n t a i n i n g t h e

secretory products.

The pool

size

in c p m d i v i d e d b y t h e u p t a k e per h o u r b y t h e b a c t e r i a
g a v e a n e s t i m a t e of t u r n o v e r
some cases

the counts

time

in t h e m i c r o b e s

(minus t h e a d s o r p t i o n blank)
an y u p t a k e .

using

the

were

Three alternative

sible on these

occasions:

substrates,

( rem o v a l t i m e ) .

(2)

after incubation

i n s u f f i c i e n t to d i s c e r n

interpretations were p o s ­

(1)

the b a c t e r i a w e r e
14

the

In

C

not

labelled o r g a m c s

were

be i n g d i l u t e d w i t h a large p r e - e x i s t i n g pool of the same
compounds,

or

(3)

another molecule
compound

in t h e

substrate

inhibition or

restricted
secretory

the u p t a k e o f t h e m a j o r

pool.

A c o m p a r i s o n of G l u c o s e — 14 C u p t a k e
untreated water

samples was used

of b a c t e r i a l upt a k e activity.
were assimulating

in u p t a k e o f
uptake of

bottles.

enzyme
sent

34).

Such delay

control

in

and

for losses

case the b a c teria

the c o n t r o l

O n e t y p e of t i m e c o u r s e
and

glucose showed that

14

C was

taken

up a c t i v e l y

could have b e e n caused by

i n h i b i t i o n o r r e p r e s s i o n by o t h e r o r g a n i c s p r e ­

in the w a t e r

Gaudy,

C

in t r e a t e d

secretory p r oduct was delayed

60 m i n u t e s w h i l e g l u c o s e —
(F igu re

14

secretory products
labelled

as a

In e a c h

the g l u c o s e —

(u n t r e a t e d s a m p l e s )

repression by

Ga u d y ,

( S t u m m - Z o l l i n g e r , 1966;

and Komolrit,

an d S t u m m - Z o l l i n g e r , 1969).

196 3; M a t e l e s
Pseudomonas

Gaudy,

1962;

and Chain,

1969;

aeroginosa would

Figure 34.

151

Time course of the uptake of secreted organic carbon from phytoplankton
photosynthesis in comparison to uptake of glucose.

40

1600

GLUCOSE UPTAKE 1200

E

CL

U

800

152

UJ

¥

o

2

x>

CL

3

3

K

- 10

400

o

u
o

90

MINUTES

120

153

not

t a k e u p g l u c o s e at a l l

as l o n g

as o n e o f t h e

glycolate,

succinate,

and R o m a n o ,

from a m i x e d

small organic
or

lactate)

in p r e p a r a t i o n ) .

acids

and g a l a c t o s e
Other
lar

there

growth

t i m e —c o u r s e p a t t e r n s

to t h a t o f g l u c o s e —
The

14

(Mukkada

S e q u e n t i a l u t i l i z a t i o n of

is a s e q u e n t i a l

in d i a u x i c

(acetate,

w e r e present

particular compounds ha s been observed
for e x a m p l e ,

substrate m e d i a

in sewage,

u t i l i z a t i o n of g l u c o s e

(Stumm— Z o l l i n g e r , 1966).

sh o w e d

immediate uptake

third h y p o t h e s i s assumes

that

t h a t a s s i m i l a t i o n of that p r o d u c t
14

little

measured

the

14

times

occurred w h e n

organic materials was

t h e lo w e s t

winter).

the

when
Ma y

the
22,

between

Conversely,
percentage

June

15)

The

substrate availability and

The

limit of

secretory—product

g i v e n a v a l u e of
ti m e s

(Figure

highest

(November

3,

t u r n o v e r time,

to u t i l i z e p e a k
the t e c h n i q u e

from

suggests that
l eve ls of

sub­

for d e t e r m i n i n g
100 hours;

accordingly,

no u p t a k e w a s e v i d e n t w e r e a r b i t r a r i l y

"100

35).

in t h e

inverse relationship

turnover was about

on all points when

fastest

the secretion of

these d a t a and f rom kinetic bioassays,

strates.

The

turnover times o c c u r r e d

secreted was t h e

the b a c t e r i a a r e u n a b l e

in t h e

(3m u n d e r t h e ice

longest

( F i g u r e 35).

C—secretory

i n c l u d e d so

C t h a t no u p t a k e c o u l d b e m e a s u r e d .
turnover

simi —

C.

p r o d u c t s w e r e so d i l u t e d by p r e - e x i s t i n g p o o l s
water

where,

hr s"

for t h e

isopleths of turno v e r

Figure 35.

Isopleths of turnover of algal secretory organic carbon by
heterotrophic uptake of the in situ bacteria, Duck Lake,
1968-1969. Values of 100 hrs are not real, but assigned
maximum values when no uptake was found (see text).

e x tr a c e llu la r

o rg

C tu rn o v e r

(m )

h 20/WO

,1

1060

DEPTH

10 60

'2 0

10

10! Si
i __ L
SEP

OCT

NOV

D EC

JA N

FEB

MAR

A PR

MAY

JU N

JU L

AUG

SEP

156
The m e a n annual
of

algae was m a x i m a l l y

Th u s ,

turnover of
2 0.4 h o u r s

the secretory p r o d u c t s

o n t h e a v e r a g e of o n c e
(Figure

36)

shows

secretion,

by h e t erotrophic u p t a k e .
time were

turnover was very
secretion was
L.
Table

(V
max

A depth profile
19 69,

during a

(probably B o t ryococcus
b e t w e e n the processes

Quantity

secreted

assimilated

and s e c r e t i o n —p r o d u c t

inversely related.

u p o n the amounts

cellular

3m

3 June,

interrelationships

of production,

the r e a l p o i n t s .

in D u c k Lake w ere

from Duck Lake on

the

fo r all

e v e r y 24 h o u r s .

b l o o m of an unknown alga at
sp.)

secretory products

Time

because

s h o r t at

secreted

0— lm,

turnover

and turnover

l ags o b v i o u s l y d e p e n d
the

Tt =

secretion—product
1 hr,

where

t h e least.
Flanktonic Production
Heterotrophy

and B a c t e r i a l

15 s u m m a r i z e s p r i m a r y p r o d u c t i o n ,

secretion,

X 24 hours)

and g l y c o l a t e ) .

and

extra­

the s u m o f h e t e r o t r o p h i c

for t h r e e s u b s t r a t e s
The ratio

(glucose,

potential
acetate,

of h e t e r o — t r o p h i c p o t e n t i a l

to p r i m a r y p r o d u c t i o n s h o u l d b e c o n s t a n t o n e a c h d a t e
if p r o c e s s e s o f n u t r i e n t c y c l i n g
at e q u i l i b r i u m .
cate variable
sition

Deviations

ti me

and c a r b o n c y c l i n g w ere

from constancy

should

indi­

lags b e t w e e n p r o d u c t i o n a n d d e c o m p o ­

in t h e p l a n k t o n o r a n e x t e r n a l p e r t u r b a t i o n to

t h e s yst em.

Time

l ags

c o u l d be c a u s e d by t h e

a c c u m u l a t i o n or b y n o n s y n c h r o n o u s
t r o p h i c an d h e t e r o t r o p h i c

diel

activity.

cycles

substrate
of a u t o -

Figure 36 . Vertical profiles of primary production, algal secretions, per­
centage extracellular release, and turnover of algal organic
secretions by heterotrophic bacterial uptake, Duck Lake, 3 June,
1969. Light bottles {----- ) and opaqued bottles (------ ).

158

C

E

■w
*

r>

i
a
u

r>
*

m

3
3

T"

TABLE 15,

Comparison of autotrophy vs. potential heterotrophy in two lakes on the same days at lm.

Insolation (g cal cm

-2

day

-1

)

Lawrence Lake:
^
^
Primary Prod, (mg C m
day )
Extracellular P.P. (mg C
day"l)

13 May

10 June

469

611

31,7
0.5

64.4
1.5

9 July

432

19 July

95

5 Aug

414

73.2
1.2

25.3
0.8

50.9
1.5

21 Aug

8 Sept

507

62.4
1.9

Heterotrophic Potential
Vmax(mg C m 3 day 3)
glucose
acetate
glycolate
Total
Hetero. Potential 1° Production
Duck Lake:
Primary Prod.
Extracellular Primary Prod.

1,03
4.65
5.45

0.72
1.41
8.56

1.83
5,90
17.12

2.60
15,78
33.84

1.65
7.29
19.97

4.31
5.85
5.86

11.13

10.71

24.85

52.22

28.91

16.02

0.35

0.16

0.34

2.06

0.57

0.26

101.3
5.6

146,5
3.6

164.2
2.1

42.1
0.6

82.5
2.7

104.9
3.3

76.1
1.5

Heterotrophic Potential
glucose
acetate
glycolate

1.96
11.59
12.86

3.29
13.08
28.66

3.91
55.92
57.82

1.60
138.48
17.62

1.80
8.64
55.68

3.37
60.96
68.16

Total

26.41

45.03

117.64

157.70

66.12

132.49

0.26

0.31

0.72

3.75

0.80

1.26

Hetero. Potential 1“ Production

7.5
82,
63.
153
2.0

160
In L a w r e n c e L ake
potential
varied
The

f r o m 0.26

increased

occurred

and 19,

(19 38)

observed

bacteria
In this

except

for Jul y 19

that c a u s e d
of t h e

the h i g h e s t

entire year

lakes,

in both

on July

17,

concentration

(lm) .

Henrici

large n u m b e r s

but not into

of soil

seepage

lakes.

the h e t e r o t r o p h i c m e t a b o l i s m o f b o t h

lake

(L awr enc e Lake)

i n D u c k Lake

heavy rainfall

that r a i n s w a s h e d

instance

(July 19).

Th e one anomolous v a l u e

into drainage

the seepage

the s u m m e r

in September,

after a v e r y

of humic mate r i a l s

to p r i m a r y production

once reaching 2.06

throughout

3.75.

1969,

r a t i o of h e t e r o t r o p h i c

substrates

i n M a y to 2. 01

it r e a c h e d

lakes
18,

the th r e e

f r o m 0 . 1 6 t o 0.57,

ratio

when

for

the

(Duck Lake)
was

primary production.

a n d the d r a i n a g e

lake

stimulated greatly c o mpared
In D u c k L a k e the

to

i n t r o d u c t i o n by

r a i n f a l l r u n o f f w a s e x c l u s i v e l y to the a c e t a t e pool;
in L a w r e n c e Lake,

to g l u c o s e ,

glycolate pools.

Thus

and/or bacteria

in to t h e

acetate,

and

introduction of organic
lake with heavy

apparently d o e s have p r o n o u n c e d
t r o p h i c m e t a b o l i s m in t h e

effects on

the

hetero—

epilimnion.

primary production

in t h e r a n g e

Lake)

the n o r m a l v a r i a t i o n

time

substrates

rainfall

If t h e r a t i o of t o t a l h e t e r o t r o p h i c

approximates

especially

0.16-0.57

potential

to

(in L a w r e n c e

( a c c o u n t i n g for

lags b e t w e e n p r o d u c t i o n a nd d e c o m p o s i t i o n ) , then

higher ratios may

indicate a higher

sustained

level of

161

organic

input from littoral or allochthonous

Wetzel

(1969)

has

investigated the amounts

li ng m e c h a n i s m s o f

an e x o s m o t i c

dissolved organic carbon
of g l u c o s e )

laboratory under

(1970)

measured

species

the

of aquatic

their production.
14

C-organic

meters

(including a hig h c o n c e n t r a t i o n

plants
Allen

in L a w r e n c e
(1969b,

once

—1
yr

conservative.

(Miller,

1971).

in s i t u

t o 1 — 3% o f

measured
th is

plants

day

entire

—1

.

lake

(1969),

t his v a l u e

is

(Rich,

1970;

8 7.9

R i c h et; al ■ ,

r e l e a s e w e r e o n l y 3%
-2
-1
thi s w o u l d b e 2.6 4 g m
yr
is a l m o s t

epiphytic

s e c r e t e d DO C

(Wetzel and A l l e n ,

g C

exosmotic

That

A very thick

release of

the

unpublished data).

as m u c h as the

2.66 g m — 2 y r — 1 s e c r e t e d b y p h y t o p l a n k t o n

s tud y.

pelagic

2

in

organic w e i g h t
-2
in L a w r e n c e L a k e w a s 262 g m

of t h e p r i m a r y p r o d u c t i o n ,
—

that

The m e a n a n n u a l

If s e c r e t i o n a n d

7.2 m g m

estimated

acutus.

in m i d - s u m m e r

studies

aquatic plants

for the

al.

several

their estimated net primary production was

—2

or

showed

in 0— 4m of w a t e r a m o u n t e d

On t h e b a s i s of W e t z e l ' s

m

1971)

products may diffuse

net carbon-C'*'^ a c c u m u l a t i o n

of r o o t e d

Rich et

L a k e and

f r o m s u b m e r g e d p o r t i o n s of S c i r p u s

probably

flexilis)

sterile conditions.

Naj as s e c r e t i o n m e a s u r e d

and

(N a j a s

s t a n d i n g b i o m a s s o f Naj as an d o t h e r

exosmotic

Lawrence Lake

and c o n t r o l ­

l o s s o r s e c r e t i o n of

from aquatic angiosperms

in the

sources.

1971,

in

community mediates

from rooted
and Allen,

aquatic
1969,

1971).

162

This

release

littoral
all of
of

is l o c a l i z e d

zone.

In D u c k

the w a t e r

in t h e

secretion mix with

in c o n t r a s t

Lake the
lake;

the s u m m e r ,

volume of water
s e c r e t i o n by
primary

s o u r c e of

tsee W e t z e l a n d M a n n y ,

ratio

in D u c k L a k e

the m o r e intensive

s i t i o n of

annual

bacterial

substrates

in h e t e r o t r o p h i c

aquatic

plants

than

1972).

potential

its d e c a y .

growth and d e c o m p o ­

probably provided more

through the

The

summer

increase

to a p e a k

t h e b u i l d - u p of m a c r o p h y t i c

O n th is

last date,

plant biomass was visibly decaying
floating masses.

increased through

in L a w r e n c e Lake.

8 September coincided with

large

zo ne i n c l u d e s

the c o m b i n e d h e t e r o t r o p h i c p o t e n t i a l :

planktonic production

biomass and

a n d in t h e

or higher amounts

Direct

c an be a t h i r d

dissolved organic carbon

on

similar

to L a w r e n c e Lake.

Because

littoral

a m u c h smaller

rooted aquatic plants

out

in t h e e p i l i m n i o n

m u c h of t h e

and c o l l e c t i n g

In a d d i t i o n ,

there was

in

a marked

i n c r e a s e of h u m i c c o n c e n t r a t i o n at t h e 3 m c o n t o u r w h e r e
organics released
slowly

f r o m the s e d i m e n t s c o u l d d i f f u s e

into s u r f a c e w a t e r s .
In c o n c l u s i o n ,

heterotrophy

in L a w r e n c e a n d D u c k

several points.

(1)

differing sources,
glucose

th e c o m p a r i s o n

acetate

f r o m the p l a n k t o n .

of b e n t h i c

sources

lakes

Specific organic

e.g.

(2)

of b a c t e r i a l
illustrated

substrates have

f r o m t h e b e n t h o s a nd
The relative

for p e l a g i c h e t e r o t r o p h s

importance
is d e p e n d e n t

1 63
upon

the c o n t r i b u t i o n o f th e p r o d u c t i o n of the r o o t e d

aquatic

plants

to t h e

or m o r e g e n e r a l l y ,
of th e

lake.

(3)

t o t a l c a r b o n b u d g e t of

the r a t i o of
Surface

runoff

following heavy

increase bacterial

surface waters.

(4)

products.

(5) T h e

the

l e v e l of h e t e r o t r o p h y

algal

processes,

blooms

probably

and r o o t e d

rainfall
in

in b a c t e r i a l

supply of algal s e c r e t o r y

s e a s o n a l l y by s u b s t r a t e s d e r i v e d
biological

heterotrophy

Day-to-day variation
upor

la ke,

s u r f a c e a r e a to v o l u m e

can dramatically

heterotrophy depends

the

aquatic

is s u s t a i n e d

from longer-termed

f r o m d e c o m p o s i t i o n of
plants.

V.

INTERPRETATION AND

INTEGRATION

The c a r b o n cycle of the epilimnion
was examined w i t h
algal
were

secretions

total

(2)

for

(1)

Budgets

(5)

sedimentation of particulate carbon,

bacterial
and

compounds,

organic

carbon compounds.

integrated with other

(6)

1970).

benthic

in the
the

f u n c t i o n of

s y s t e m was d e d u c e d
the a n n u a l

secreted

standing

respiration,

zone,

and

littoral Chydoridae

these

general

heterotrophy of

littoral

et a l . i n p r e p a r a t i o n ;
The

turnover of

s t u d i e s o n the g r o w t h a n d

production and

Wetzel

some small

Lake was

water

of

input of hum i c

The work on Lawrence

plants,

epiphytic community

(4)

bacterial

crops of aquatic
chemistry,

ice,

heterotrophy of

organic

lation dynamics

and m e c h a n i s m s

primary production and

lake m e t a b o l i s m u n der

materials,

lakes

e m p h a s i s o n the u p t a k e of

by bacteria.

investigated

secretion,
(3)

special

in t w o

Allen,

19 69b ,

components

from c o m p a r i s o n of

the p o p u ­

(Rich,

1970;

1971;

Ke en,

in t h e

tw o

th e

lakes

lake
through

cycle.

The d a t a c o l l e c t e d
steady state

system,

suggest

relative

to

164

the o p e r a t i o n of
the

short

life

a

span of

165
the algae and
mean

bacteria.

During the g r o w i n g season

t u r n o v e r of p a r t i c u l a t e

constant,

while

organic

instantaneous rates

T u r n o v e r of C a r b o n Pools

is r e l a t i v e l y

could vary widely.

(days)— Summer 1969

POC-production

POC-sedimentation

Cell C

15 (5— 38)

35 (25-55)

0.94 (0.14-3.7)

Lawrence
Lake
Duck
Lake

2 2 ( 8 — 50}

not d e t e r m i n e d

Primary production varied
200— fold

carbon

th e

7 . 9 ( 2 — 19)

2 0— fold i n L a w r e n c e L a k e

and

i n JDuck L a k e .

A simple compartmental model
linear d i f fe rentia l

equations

between components.

to d e s c r i b e

time

lags a n d a l i n e a r r e l a t i o n s h i p b e t w e e n c o m p o n e n t s .

The

can

be

t he b a s i s

the c a r b o n poo l

sizes

for

tonic

(1)

t hat m a n y

s u b s y s t e m and m a y

n a n t of s o m e m a j o r
o n J u l y 19),
history of

(2)

theoretical

fl o w s

in L a w r e n c e

a c t u a l l y be
events

there

material

at

and D u c k

influence

(4)

that

lakes

the p l a n k ­

a dominant determi­

(for e x a m p l e th e r a i n f a l l

are t ime

l i g h t ) , (3)

the b o t t o m c a n a f f e c t p l a n k t o n i c
and

However,

lags

(e.g.

previous

t he p l a n k t o n d e t e r m i n e s p r o d u c t i o n m o r e

the daily v a r i a t i o n in

la kes ,

d e t e r m i n a t i o n of

l ake s.

perturbations

annual

that

s y s t e m assumes

in d i f f e r e n t

q u a n t i f i c a t i o n of c a r b o n
suggested

closed

the transfers
no

model

This

is p r e s e n t e d u s i n g

that

releases

heterotrophy

than

from

in s h a l l o w

b i - a n n u a l r e s u s p e n s i o n of p a r t i c u l a t e

thermal o v e r t u r n disrupts

the

normal cont r o l s

166

of p o o l size

in t h e m o d e l .

cannot predict accurately

Thus,

this

a ny p a r t i c u l a r

E a c h t e r m in t h e d i f f e r e n t i a l
d e t e r m i n e d by
or

independent parameters

f i x e d by l i n e a r

most useful
presented

to p o i n t

mechanisms

Duck
by

than

by

3X

(Table 9).

strictly depend

by

2X,

organic

carbon

but

indicate

that

ra ther,

crop above

s ome

SOX,

a function of

in the e p i l i m n i o n
POC and

the r a t e of r e m o v a l
the

threshold

however,

in

s i z e of

level.

not

a function

the

flux of

The correlation
and

sedi­

the c o n s t a n c y
in L a w r e n c e

of POC was

the POC

standing

R e s u s p e n s i o n of

bottom material was potentially greater
D u c k Lake;

2 X , in DO C

The concen­

t i m e s by s e d i m e n t a t i o n

linearly dependent upon

that

and b a c t e r i a l h e t e r o t r o p h y

of epilimnetic

the POC removal

Lake

POC by

organic c a r b o n was not

b e t w e e n t h e a m o u n t of P O C

of

between

showed

cel l c a r b o n by

t h r o u g h t h e a lga e.

m e n t a t i o n rates

transfer

on p r i m a r y p r o d u c t i o n .

biomass,

is

it is

Phytoplanktonic biomass did

t r a t i o n of p a r t i c u l a t e
of a l g a l

this

work on

in t h e t w o l a k e s

in a l g a l

primary production

like

(Appendix B ) .

s i z e s a n d r a t e s of

1.5X,

(o fte n n o n - l i n e a r )

for m o r e

L a k e e x c e e d e d L a w r e n c e L a k e in

less

equations m i g h t be

further research and

o u t the n eed

of o r g a n i c c a r b o n

annual cycle.

A model

in l a k e c a r b o n c y c l i n g

Comparing
pools

regressions.

in d i r e c t i n g

simple model

in the

shallower

the p h y t o p l a n k t o n c o n t r i b u t e d m o r e

167
o f the t o t a l
of log P O C
r = -0.15
material

POC there

and
in

t h a n in L a w r e n c e L a k e

log c e l l v o l u m e ,

Lawrence

is d e n s e r

Lake).

r =

Thus

(correlation

0.63 i n D u c k Lake;
resuspended

than planktonic

detritus

bottom

and

only briefly

in the w a t e r c o l u m n c o n t r i b u t i n g t o

PO C for o n l y

a s hor t t i m e

after resuspension by

resides
the
currents.

T h e m e a n c o n c e n t r a t i o n of d i s s o l v e d o r g a n i c c a r b o n
a t lm in D u c k
Lake.

The

La ke w a s

D O C pool

o n l y 1.4X

larger than

in D u c k L a k e d i d

doubled p r i m a r y p r o d u c t i o n nor the
hu mic m a t e r i a l s .

Because

and s e c r e t i o n o c c u r r e d
o f DOC m u s t
carbon

flux through

the higher

Possibly,

po ol

size.

Szekielda

the c o n c e n t r a t i o n

(1968,

t he

inorganic

of p r i m a r y p r o d u c t i o n

affects

1969)

than

a limiting

interaction

and b a c t e r i a l d e c o m p o s i t i o n w h i c h

i n p u t of

algal p r o d u c t i o n

by s om e t h i n g other

it.

nutrient determines the

not r e f l e c t th e

increased

in Duck Lake,

be regulated

in Lawrence

t h e m e a n DOC

developed

a model

for

m a r i n e p l a n k t o n that a s s u m e d p r o d u c t i o n e q u a l l e d d e c o m p o ­
s i t i o n of o r g a n i c m a t t e r

and

that

p o o l w a s b a s e d on s t o i c h i o m e t r i c
predict oxygen,
seawater
might

phosphate,

f r o m its o r g a n i c

the c o m p e t i t i v e

decomposers

as

reactions.

the organic
He could

and n i t r a t e c o n c e n t r a t i o n of
content,

and vice versa.

H ow

relationship between producers

it e f f e c t s

n u t r i e n t c o n t e n t of

t h e size o f

the

DOC

pool

sys t e m ?

size be l i n k e d

to

and

168

First order reaction kinetics d escribe
how enzymes combine w i t h specific
bacterial

heterotrophs

strates,

Thomas
by

Eppley,

Eppley and Cotsworth
(1969)

have

the lowest

velocity.

inorganic

was
upon

(e.g.

Bacteria,
showed

(196 8),

sub­

and McCarthy

a n d E p p l e y a nd

Generally

transport constants

continued growth

(1933)

Rogers,

shown that algae c o m p e t e

Algae may develop

nutrients when

1969).

how

concentrate carbon—energy

first-order mechanisms.

have

substrates,

an d h o w b a c t e r i a a n d a l g a e c o n c e n t r a t e n u t r i e n t s

from dilute solution.
(196 9),

functionally

too,

and

enzymes

nutrient

the

for N O ^ —

smaller algae

slowest uptake

to h y d r o l y z e o r g a n i c

sources

cannot support

phosphotases, Fitzgerald
may be nutrient

th at F u c u s d e c o m p o s e d

et a l .,

limited.

Waksman

faster when N O ^ —

a d d e d and t h a t t h e r a t e o f m i n e r a l i z a t i o n d e p e n d e d
the a m o u n t o f o r g a n i c

Ulva decomposed more
circumstances,

nitrogen

rapidly than Fucus

in p a r t b e c a u s e o f

content.

Waksman

bacteria

in s t o r e d

glucose

until

dations

of c a r b o n

in t h e p l a n t

and

Renn

(1936)

added.

identical

its g r e a t e r n i t r o g e n
similarly

seawater w o u l d not

nitrate was

under

tissue.

found t h a t

o x idize added

Thus,

bacterial

oxi­

s u b s t r a t e s m a y be l i m i t e d by some

nutrient.
Algae
nutrient.

and b a c t e r i a may co m p e t e

Addition of

organic substrate or

this

for

a limiting

nutrient or change

in i n s o l a t i o n m a y

shift

in an

the

169
competitive

advantage

to t h e b a c t e r i a o r t o

p l a n k t o n an d u p s e t o r c h a n g e
and

inorganic

adding

pool

inorganic

rich waters
dation of

sizes.

the equilibrium organic

Ryhanen

(1968)

in F i n n i s h b o g s

resulted

first

flora.

reserve the b a c t e r i a had

advan t a g e over

the algae

of p o o l

s i z e of o r g a n i c

depends

upon a complex

for

i n the o x i ­

the c o m p e t i t i v e

carbon in aquatic

study.

Duck Lake h ad

lakes

A p p e n d i x B) .

dissolved organic carbon pool was
than

the greater

is o f t e n l i m i t i n g

(Wetzel,
Despite

influx of non— algal humic materials

in D u c k L a k e w e r e

systems

and energy.

availability

t o a l g a l g r o w t h in h a r d w a t e r

primary production

T he c o n t r o l

interaction between the bacteria

s t o r e of p h o s p h a t e w h o s e

M a n n y ejt al_. , 1971;

W i t h the h i g h

the n u t r i e n t s .

for a v a i l a b l e n u t r i e n t s

In the p r e s e n t

1965b,

i n t o D u c k Lake,

The

supplied with more organic

t h e D OC p o o l m o r e c o m p a r e d

mation

t h a n the b a c t e r i a

in D u c k L a k e w a s
ratio was

21: 1

to its

the C : N ratio

13:1, w h i l e

(Manny et a l .,

in L a w r e n c e
1971).

bacteria

substrates
t h e m to

r a t e of

in L a w r e n c e La k e .

d u r i n g t he w i n t e r

t he

smaller p er unit

in L a w r e n c e Lake.

reduce

1971;

the greater

a higher nutrient content which allowed

example,

that

th e l a r g e o r g a n i c c a r b o n r e s e r v e b y t h e p r e ­

DOC energy

with

found

nitrate or phosphate to b r own humus-

v i o u s l y N and P s t a r v e d b a c t e r i a l

an d a l g a e

the p h y t o ­

for­

For

in the DOC
Lake

the C : N

The potential

170
uptake rates
three

times

for
as

simple organic

h i g h in D u c k L a k e c o m p a r e d

Lake while the production was
(Table

13).

The bacteria

solved organic

l a c k of o r g a n i c
the a l g a e

light

are

energy.

As

low energy and
Lake).
of

lakes,

substrates

in t h e w a t e r .

(energy)

are

limited

and nutrients,

accumulates

c a r b o n of

(e.g.

is m a i n t a i n e d

Lawrence
by r e m o v a l

on s e t t l i n g precip i t a t e d

limitation

Sphagnum removes

same d i s ­

the decomposers

lakes o l i g o t r o p h y

nutrient

potentially

a result dissolved organic

and iro n adsorbed

In b o g s

as h i g h

l i m i t e d o n l y by n u t r i e n t s , n o t by

nutrient value

In m a r l

to L a w r e n c e

c a r b o n at a b o u t t h e

carbon concentration

In o l i g o t r o p h i c

but

only twice

lv m a x ) w e r e

in D u c k L a k e w e r e

assimilating more organic

by

substrates

CaCO^.

is m a i n t a i n e d b e c a u s e

ions f r o m t h e

In s l i g h t l y m o r e

incoming water
eutrophic

(Clymo,

1963,

1964).

algae

produce organic carbon of high nutrient and energy

content w h ich the bacteria decompose
a

faster rate,

maintaining

and m i n e r a l i z e

t he DO C p o o l

centration p e r unit primary production.
proposed

after

e x a m i n a t i o n of

experimentally confirmed.
exact biochemical
bacterial
carbon
ation

or

For

these

conditions

two

at

at a l o w e r c o n ­
This

hypothesis,

lakes,

the immediate

thermodynamic

the

nature of

c a n be

purposes

the

the al g a l -

interaction which determines dissolved organic

levels

n e e d n o t b e k n o w n to a p p r e c i a t e

in c l o s e d

aquatic

systems.

its o p e r ­

VI.

1.

Variation

CONCLUSIONS

in a l g a l

contrasting
light over

primary production

lakes was controlled primarily by
the

annual

c ycl e,

but

the r e c e n t

history of primary production was
indicator
for the
2.

Rates of

in t w o

a better

for p r e d i c t i o n of d a i l y p r o d u c t i o n

s u c c e e d i n g d a y or t w o
algal

than was

light.

secretion during photosynthesis

w e r e d e t e r m i n e d p r i m a r i l y by t h e r a t e s o f p r i m a r y
production.

Species differences

determined whether cell number
would correlate more
3.

Percentage

algal

in th e p l a n k t o n

or cell volume

strongly with secretion.

secretion

increased with

i n c r e a s e d d e p t h as t h e r a t e o f p r i m a r y p r o ­
duction decreased.

The p e r c e n t a g e algal

was higher on most dates
marl
4.

secretion

in t h e m o r e o l i g o t r o p h i c

lake.

In c o m p a r i n g t h e two
particulate organic

lakes,

the

size of

the

carbon standing crop was

171

proportional

to

t h e rates of a l g a l

d u c t i o n a n d n o t t h e standing c r o p

p rim ary p r o ­
of p h y t o p l a n k ­

ton.
P a r t i c u l a t e o r g a n i c carbon s e d i m e n t a t i o n of
s eston was

l i n e a r l y related t o

the

the

size of t h e

p a r t i c u l a t e o r g a n i c carbon s t a n d i n g crop d u r i n g
th e g r o w i n g s e a s o n resulting

in

a con sta nt

t u r n o v e r time.

A b o u t 4 0% of t h e

organic c a r b o n

produced

trophogenic z o n e

was decomposed

in t h e

there.
The

p h y t o p l a n k t o n i c primary p r o d u c t i o n and

respiration were
whole

a small p r o p o r t i o n of the

l ake c a t a b o l i s m during t h e

Heterotrophic

winter.

u p t a k e of small o r g a n i c s u b s t r a t e s

was controlled

p r i m a r i l y by t e m p e r a t u r e o v e r

annual

T h e uptake of g l u c o s e - U -

cycle.

glycolate—U—
secretion,
"humic"

14

C correlated w i t h

Acetate uptake

correlations with

secretion,

d i s s o l v e d o r g a n i c carbon, a n d
upon

temperature

strates.

C

and

lev e l s of a l g a l

d i s s o l v e d organic c a r b o n ,

a cid s.

14

the

and/or

showed negative

and
a

t h a n the u p t a k e

w i t h total
lower d e p e n d e n c e
o f other s u b ­

It w a s p osi ti v e l y c o r r e l a t e d w i t h

173
humic

acid c o n c e n t r a t i o n

sources were

indic a t i n g that

significantly different

it s

than glucose

and g l y c o l a t e .
8.

Diurnal,

weekly,

h e t e r o t r o p h y of

a nd a n n u a l v a r i a t i o n i n b a c t e r i a l
small organic

(glucose)

corresponded to extra-cellular

l oss o f o r g a n i c

carbon during photosynthesis.

Heterotrophic

uptake potential
coupled
9.

substrates

to t h e

Terrestrial

oscillated daily,

level of

runoff

on th e h u m i c

acid

heterotrophy

in

substrate

and was
availability.

had p r o n o u n c e d d i r e c t e f f e c t s
c o n c e n t r a t i o n and b a c t e r i a l

the t r o p h o g e n i c

z one o f b o t h

lakes.
10.

T h e s i z e of t h e d i s s o l v e d o r g a n i c
per uni t algal produ c t i o n v a r i e d
the total phosp h o r u s
the

11.

f l u x of o r g a n i c

Carbon
the two

budgets
lakes

d u c t i o n was
community

for

in t h e

carbon pool
inversely with

system,

rather

c a r b o n t h r o u g h the D O C
the p l a n k t o n i c

showed

pool.

s u b s y s t e m of

that algal primary p r o ­

less

important

to

in t h e

shallower

lake with other

s o u r c e s of DOC.

than

th e h e t e r o t r o p h i c

174
TA B L E 16.

A n n u a l p e l a g i a l carb o n b u d g e t s for Lawrence a n d Duck Lakes.

Annual budget

P r i mary produ c t i o n ,
{g C m -^ y r “ l)

Lawrence L ake

Duck Lake

phytoplankton
46.7

48.4

2.7

3.9

32.8

n.d.

196.4

n.d.

8.1

n.d.

3.7

8.3

79.2

103.6

117.5

n.d.

—2
-1
Rooted aquatic p l a n t s e c r e t i o n (g C m
yr
)
(3% of p r o d u c t i o n a f t e r Rich 1970b)

2.6

n.d.

-2
-1
Autolysis of al g a l cells (g C m
yr
)
(20% x (primary prod. - 30% P.P))

6.5

6.8

Al g a l secr e t i o n

(g C m

POC sedimen t a t i o n

-2

(g C m

Ca C O j sedi m e n t a t i o n

yr

-2

-1
yr

)

-1

(g C a C O ^ m

-2

), 11m
yr

-1

)

A l lochtono u s d i s s o l v e d o r g a n i c carbon
i n t roduc t i o n (g C m - ^ y r - 1 )
Hu m i c d i ss o l v e d o r g a n i c c a r b o n ( g C m
Benthic r e s p i r a t i o n
as g
m “ 2 y r - l)

-2
-1
y r )

(winter time rate

Es timates of o t h e r studies
Be n thic r e s p i r a t i o n
(g C m “ 2 y r “ l)

Estimated total

(Rich 1970b)

input to the DOC pool

P e r cent of the p l a n k t o n p r o d u c t i o n

20.5

(18.0)

44%

♦Not c o m p a r a b l e to Lawrence Lake total; this lacks m a c r o p h y t i c
excretion, a n d n o n p l a n k t o n i c organic c a r b o n o t h e r than h u m i c
materials.

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s t u d i e s o n d i s s o l v e d c a r b o h y d r a t e s in
C a p e C o d w a t e r s III.
S e a s o n a l v a r i a t i o n in
Oyster Pond and Wequaquet Lake, Massachusetts.
L i m n o l . O c e a n o g r . 1 1 : 2 4 9 — 256.

W a k s m a n , S. A.
1933.
M a r i n e b a c t e r i a and t h e i r r o l e in
t h e c y c l e o f l i f e i n the sea.
I.
Decomposition
o f m a r i n e p l a n t a n d a n i m a l r e s i d u e s by b a c t e r i a .
Biol. Bull. 6 5 : 5 9 - 7 9 .
a n d C. E. R e n n .
1936.
D e c o m p o s i t i o n of o r g a n i c
m a t t e r in s e a w a t e r b y b a c t e r i a .
III.
Factors
i n f l u e n c i n g t h e r a t e of d e c o m p o s i t i o n .
Biol.
Bull.
70:472-483.
Watt,

W.

D.
1966.
R e l e a s e of d i s s o l v e d o r g a n i c m a t e r i a l
from cells of phytoplankton populations.
Proc.
R o y a l S o c . L o n d . B 1 6 4 : 5 2 1 — 551.

__________ .
1969.
P r i m a r y p r o d u c t i v i t y ra t e s o f i n d i ­
v i d u a l p h y t o p l a n k t o n s p e c i e s in r e l a t i o n to p o p u ­
l a t i o n d e n s i t y a n d d i v e r s i t y . p233.
XI I n t e r ­
national B o t a n i c a l Congress Abstracts, Seattle,
W a s h . ( A b s t r .>
__________ a n d G. E. F o g g .
1966.
T h e kinetics of e x t r a ­
cellular glycellate production by Chlorella
p y r e n o i d o s a . J. Exp. Bot. 1 7 : 1 1 7 - 1 3 4 .
W e i n m a n n , G. Von.
19 7 0 .
G e l o s t e K o h l e n h y d r a t e und
a n d e r e o r g a n i s c h e S t o f f e in n a t u r l i c h e n G e w a s s e r n
u n d in K n l t u r e n v o n S c e n d e d e s m u s q u a d r i c a u d a .
A r c h . H y d r o b i o l . S u p p l . 3 7 : 1 6 4 - 2 4 2^
Warshaw,

R. L., P. J. B u r c a r , and M. C. G o l d b e r g .
1969.
Interaction of pesticides w i t h natural organic
material.
E n v i r o n . Sci. T e c h n o l . 3 : 2 7 1 — 273.

W e s t e n h o u s e , R. G.
1969.
Dichromate
sition and c a r b o n estimation.
26 :16 64— 16 67.

reagent decompo­
F i s h Res. B d . Can.

188
Wetzel,

R. G.
1964.
A comparative study of the primary
productivity o f higher aquatic p l a n t s , periphyton
a n d p h y t o p l a n k t o n in a l a r g e s h a l l o w l a k e .
Int.
Rev. ges. H y d r o b i o l . 4 9 : 1 — 61.

__________. 1965a.
N e c e s s i t y for d e c o n t a m i n a t i o n of
f i l t e r s in C — 14 m e a s u r e d r a t e s o f p h o t o s y n t h e s i s
in f r e s h w a t e r s .
E c o l o g y 4 6 : 5 4 0 — 542,
_________ . 1965b.
N u t r i t i o n a l a s p e c t s of a l g a l p r o d u c ­
t i v i t y in m a r l l a k e s w i t h p a r t i c u l a r r e f e r e n c e
to enrichment bioassays and their interpretation.
M e m 1st. Ital. I dro bio l. S u p p l . 1 8 : 1 3 7 - 1 5 7 .
__________. 1966a.
V a r i a t i o n s in p r o d u c t i v i t y o f G o o s e
and h y p e r s e u t r o p h i c S y l v a n lakes, Indiana.
Invest. I n d i a n a L a k e s a n d S t r e a m s 7 : 1 4 7 — 184.
_________ . 1966b.
Productivity and nutrient relationships
in m a r l l a k e s o f n o r t h e r n I n d i a n a .
V e r h , I nte rnat.
V e r e i n . L i m n o l . 1 6 : 3 2 1 — 332.
__________. 1967.
D i s s o l v e d organic compounds and their
u t i l i z a t i o n in two m a r l lakes.
Hidrologia
K o z l o n y 4 7 : 2 9 8 — 303.
__________. 1968.
D i s s o l v e d organic ma t t e r and p h y t o —
p l a n k t o n i c p r o d u c t i v i t y i n m a r l lakes.
Mitt
In ter nat . V e r e i n . L i m n o l . 1 4 : 2 6 1 — 2 70.
_________ . 1969.
F a c t o r s i n f l u e n c i n g p h o t o s y n t h e s i s and
excretion of dissolved o r ganic matter by aquatic
m a c r o p h y t e s i n h a r d w a t e r la kes .
V erh . Int er n a t .
V e r e i n . L i m n o l . 1 7 : 7 2 — 85.
__________. 1970.
R e c e n t and p o s t g l a c i a l p r o d u c t i o n
r a t e s of a m a r l lake.
Limnol. Oceanogr. 15:491503 .
_________ .
1971.
T h e r o l e o f c a r b o n in h a r d —w a t e r lakes.
Amer. S o c . L i m n o l . O c e a n o g r . S y m p o s i u m S e r i e s
1 :84-97.
__________ an d H. L. A l l e n .
1971.
F u n c t i o n s and i n t e r ­
actions of d i s s o l v e d o r g a n i c m a t t e r and the lit­
t o r a l zone i n l a k e m e t a b o l i s m a n d e u t r o p h i c a t i o n .
In Kajak, Z. ( e d .}.
P r o c e e d . I.B.P. S y m p o s i u m
o n P r o ductivity Problems of Freshwaters.
Polish
A c a d e m y of S c i e n c e s , W a r s a w . (In P res s).
, P. H. Rich, M. C. M i l l e r , a nd H. L. A l l e n .
(In p r e p a r a t i o n ) . M e t a b o l i s m of d i s s o l v e d an d
p a r t i c u l a t e d e t r i t a l c a r b o n in a t e m p e r a t e h a r d ­
w a t e r lake.

189
Wright,

R. T.
1970.
G l y c o l l i c acid uptake by planktonic bacteria. p521-536.
In D . W. H o o d ( e d . ) ,
Organic m a t t e r in natu r a l waters.
U n i v e r s i t y of
Alaska, College, Alaska.

__________ and J. E. H o b b i e .
196 5.
Th e u p t a k e o f o r g a n i c
s o l u t e s in l a k e w a t e r .
Limnol. Oceanogr.
1 0:2 2-2 8.
__________ and __________ .
1966.
U s e of g l u c o s e , a c e t a t e b y
b a c t e r i a and a l g a e in a q u a t i c e c o s y s t e m s .
E c o l o g y 4 7 : 4 4 7 — 464.
Zobell,

C. E. a n d D. Q. A n d e r s o n .
1936.
Observations
of t h e m u l t i p l i c a t i o n of b a c t e r i a in d i f f e r e n t
v o l u m e s of s t o r e d se a w a t e r a n d t h e i n f l u e n c e o f
oxygen tension and solid surfaces.
Biol. Bull.
71: 324 — 342.

APPENDICES

APPENDIX A
P H Y SIC All—C H E M I C A L L I M N O L O G Y O F D U C K LAKE,
K A L A M A Z O O CO.,

MICHIGAN

Appendix A
P h y s i c a l —C h e m i c a l L i m n o l o g y of D u c k L a k e ,
K a l a m a z o o C o ., M i c h i g a n
D u c k Lake was

selected

the s y s t e m a t i c d i f f e r e n c e s
reasons:

(1)

it h a d

bottom of the

be

(3)

system compared

and

(4)

opportunity

study of

for s e v e r a l

to v o l u m e

ratio;

angiosperms covering

t he

i m p o r t a n t to t h e o p e n - w a t e r
twice

(12 y g v e r s u s

chemically

to L a w r e n c e L a k e

than 1.0 m e q compared

area

it c o n t a i n e d

as L a w r e n c e L a k e

respectively);

surface

aquatic

l ak e c o u l d

planktonic microflora;
phosphorus

in c a r b o n d y n a m i c s

a high

(2) c o n t r i b u t i o n of t h e

fo r a c o m p a r a t i v e

it w a s

as m u c h

6 yg P 1 ^
a soft water

(total a l k a l i n i t y

to 4.5 m e q f r e s p e c t i v e l y ) .

for f i n d i n g m a j o r d i f f e r e n c e s

o f p l a n k t o n i c p r o d u c t i o n in t h e t o t a l

in t h e

less
The

importance

lake m e t a b o l i s m was

maximized.
Several
monitored
Methods

standard

and q u a l i t a t i v e d i f f e r e n c e s

are described

(in p r e p a r a t i o n ) .
dimicitic

limnological parameters were

previously

Temperature

pattern varying

differential.
two m e t e r s

showed

from

s t r a t i f i c a t i o n was m a i n t a i n e d

and

0®
only

to

in t h e b i o t a n o t e d .
in W e t z e l

the e x p ected
2 4 °C.

summer

g r e w to w i t h i n

in late J une and

190

The

by a 6 QC t e m p e r a t u r e

C e r a t o p h y l l u m d e m e r s u m L.

of t h e s u r f a c e

et a l .

acted

as a

191

mechanical

h i n d r a n c e to m i x i n g

d e p l e t i o n at

3m confirmed

stable during
summer

and

the

su m me r .

{F igure 37).

tha t the s t r a t i f i c a t i o n was
Anaerobisis occurred

in win t e r under the

b o t h periods.
from greater

The

ice;

t h a n 12 to l e s s

the

less

( F ig u re

( F i g u r e 39).

37).

than

3 mg 0 2 1 ^

f r o m 170

lowered

summer

the pH o f

increased decomposition of rooted
The a l k a l i n i t y

CaCOj equivalents

1 1 to

(Figure

39).

at

C a + + — 1 1. 6 m g

1m:

1

70 m g

Th e cations had

1 ^ over
th e

late

phorus

at l m

( F ig u re 40).

th e

f r o m 40 m g

the

summer

I - 1 , K+ — 1.42 m g

1
showed enrichment

1969.

in

in

A h igh c o n c e n t r a t i o n of p h o s ­

in m i d - M a y p r e c e d e d

in th e s p r i n g ,

The annual

M o s t o f the

nitrogen was

Duck

N O ^ “ = 125 y g N 1

Lake:

entire

stratum when m a crophytes were d e c a y i n g

summer

by

following annual means

Total dissolved phosphorus
the bottom

caused

the

increased

0. 24 m g

9.0

aqua t i c p l a n t s and

l- 1 , M g + + — 1.98 m g

and N a + — less t han

fall

r a i n s an d

f r o m 6.6 t o

decreased probably responding to

its CC > 2 e f f l u x .

(Fi gure 38).

the bicarbonate a l k a ­

The pH v a r i e d

By late

ranged

ymho before

T h e s u r f a c e m a x i m u m in p H w a s

an algal bloom.
p r o f i l e h ad

evolved during

t h a n 95 in J u n e w h e n s u m m e r

phytoplankton growth

linity

in the

surface oxygen concentrations

Conductivity decreased
turnover to

Oxygen

present

a b l o o m of
range was

phytoplankton
8 — 80

in t h e o r g a n i c
NQ2~ = 2 . 5

yg P 1 ^ .
f o r m in

yg N 1 1 ,

Figure 37.

192

Temperature (°C) and conductivity (umhos) isopleths in Duck Lake
from September, 1968, to September, 1969.

TEMPERATURE

DEPTH

(ai)

0

2

2b IS 16 u KM64

3
4

SEP

OCT

NOV

DEC .

JAN

FEB.

M AR

APR

MAY

JU N .

JU L

AUG

SEP.

193

(m)

CONDUCTIVITY

V100

'
>00

100 10095 .95 >00

EPTH

110 1)5120

I

I

1)0 U10 125
SEP

OCT

NOV

DEC

JAN

FEB

MAR

APR. MAY

JJN

JUL AUG. SEP

Figure 38.

Oxygen concentration (mg 0, l”1) in Duck Lake from
September, 1968, to September, 1969.
194

OXYGEN CONCENTRATION
T

DEPTH

Cm )

m

o 2
i

K)

12

. 1

1

8

"

i;i

SEP

/ a

,
NOV

i//.lii!

DEC

:/

U

x

V

Vsi

: /'

{nlf

1.
C CT

j i

I |tiiii».
1

/{

| ■

,:i

.6
4

m g O jI1

JAN. FEB.

[i
\tl ll,

MAR

\
i

APR

1

!

; . L
AUG. SEP
MAY JU M JUL

Figure 39.

196

pH and alkalinity (mg CaC03 l"1) isopleths in Duck Lake,
September, 1968, to September, 1969.

Cm)

0

DEPTH

70 72

4

SEP

OCT.

7.6 7.6 72 7.0

NOV,

DEC

JA N

FEB

MAR

APR

MAY

JU N

JU L .

AUG

SEP

Cm)
DEPTH

2 - 3045

40 45

4
SEP

O CT

NOV

DEC

JA N

FEB.

MAR,

APR.

MAY

JU N .

JU L

AUG. SEP

197

ALKALINITY (mgCaCOj I '1)

0

Figure 40

Total dissolved phosphorus (pg P 1 1; in Duck Lake, from September,
1968, to September, 1969.

TOTAL DISSOLVED
i

x2
H
a

10

S

OCT

NOV.

8

10

to

JA N

FEB

,I

a 3

SEP

DEC

h—

PHOSPHORUS
^ —

~ n -----------

200
NH^+ =
under

5 0 — 75 y g N 1 ^ , and o r g a n i c
the

ice

in F e b r u a r y

N = 5 0 0 — 550 y g N l - ^

(Manny e t al_. , 1971) .

P h y t o p l a n k t o n cell n u m b e r s and v o l u m e s
several maxima:
May,

19 69,

November,

at lm.

1968,

B i o m a s s of a l g a e d i d

directly to peak cell numbers
plankton were dominated
10y.

The

autumnal

by v e r y

primarily

an u n i d e n t i f i e d

in F e b r u a r y ,
Dinobryon

1969,

was

s p . caused

T h e m a x i m u m on M a y
and

5y.

forms,

3 at l m w a s

aureus

lake a t

l a r g e n u m b e r s of

by t h e s e

occurred over

unknown Botryococcus
v a l u e s of
carbon,

(Muell.).

in M a y

t h e y e a r of c e l l

and algal

but

samples.

G o m p h o s p h e a r i a , Anabaena,

in A p r i l .

perhaps
volume on

Braunii

(Keutzing)

A b l o o m of V o l v e x
t he w h o l e

surface of

it w a s m i s s e d c o m p l e t e l y

A m a j o r d e v e l o p m e n t of
and June yielded

volume,

secretion.

increase

6— 7y c r y p t o p h y t e

a smaller Botryococcus

subsurface

The

in c e l l v o l u m e

The maximum cell

the end of M ay ,

l es s t h a n

smaller m i c r o f l a g e l l a t e .

2 2 was a larger

(Ehrenb e rg )

Phyto­

The November pulse was

an even

(60X 35y).

42).

Rhodomonas minuta

4y c h r y s o p h y t e .

the p e a k

and P e r i d i n i u m c i n c t u m

the

and

and

not correspond

s m a l l e r n u m b e r s of an u n k n o w n s p e c i e s ,

Botryococcus
June

small

populations were

less t h a n

1969,

(Figures 41 a n d

(Skuja), smaller cryptomonads,
microflagellates

M a r c h —A p r i l ,

showed

the h i g h e s t

particulate

Larger

forms of

an

organic
Gleocystis,

T r a c h e l m o n a s , an d V o l v e x

Figure 41.

Algal cell numbers (# x 10^ 1
and algal cell volume
(u3 x 109 1"1) at lm in Duck Lake.

20

202

10

0

SEP

OCT

FEB

VAR

AF*t

MAY

J jN

SEP

Algal cell numbers (# x 10^ 1
and algal cell volume
(u3 x 109 1-1) in Duck Lake from September, 1968, to
September, 1969,

203

Figure 42,

PHYTOPLANKTON

CELL NUMBERS x l

0

tfV

2
° 3

4

SEP

OCT

NOV

DEC

JAN

FEB

MAR

APR.

MAY JUN.

JUL.

AUG. SEP

w
o
PHYTOPLANKTON

CELL VOLUMES u3x10!
—

ht

1

1------------ —

■300

SEP

OCT

NOV

DEC.

JAN

FEB.

MAR. APR

MAY

JUN.

JUL

AUG. SEP

205
globator

Cl.)

appeared

numbers reached

in l a t e s u m m e r w h e n s p e c i e s

a maximum.

increased dur i n g late

Ciliates

and r o t i f e r s also

s u mmer.

T h e r e w a s a l a r g e p o p u l a t i o n of b l u e g i l l ,
Lepomia machrochirus

Rafinesque,

hybrids

in D u c k L a k e .

crappie

have been taken

t h a n 1 5 c m long,

larger

animal

forms were

s o me L e p o m i s

A few small bass and

personal communication).
less

and

from the

lake

(Dr.

one

Gerald

T w e n t y — five bluegills,

were older

than

large

six years.

Esch,
all
The

pl ankton were noticeably scarce and the

small d u r i n g mo st of

the y e a r .

APPENDIX

B

M O D E L F O R C A R B O N - F L O W IN T H E M I C R O ­
PLANKTON OF A L A K E AT lm

Appendix
Model
Rates:
a re

specific

for C a r b o n — F l o w in -the M i c r o p l a n k t o n o f a L a k e at lm

r

, rb ,

, e 3 , e 4 , d 1 , k 2 , k 3 , and k 4

r a t e s of t h e

organism per

B

type mg C transferred per mg

hour.

Biomass:

A = algae,

solved o r g a n i c carbon,

POC

B = bacteria,

— dead

DOC = d i s ­

particulate organic

carbon.

X.

TI-

d A

^j-£- = k^A - r aA —

If

V

— e 2A +P2^

= k 2B + k 3B - e 4B ~ r b B

HI,

IV'

~ e^A

= e ^A + e 2A

- k 2B

d | t C = d lA ” e 3P O C
dCOj
dt

_
a

+ e 3POC

+

e 4B - p 2A

- k 3B - Sj^POC

A + r B + p co
- k A
b
*1
2
1

T h i s is a set o f s i m u l t a n e o u s d i f f e r e n t i a l
e q u a t i o n s w h i c h d e s c r i b e t h e system.
E a c h of the terms
is i t s e l f a r e l a t i o n s h i p d e s c r i b i n g t h e t r a n s f e r b e t w e e n
two b l o c k s .
These are o f t e n nonlinear.
The transfer
t e r m s ar e b a s e d o n f u n c t i o n a l or r e g r e s s i o n a l r e l a t i o n ­
s h i p s in t e r m s of i n d e p e n d e n t p a r a m e t e r s .
The model may
be s i m u l a t e d u s i n g t h e a n a l o g c o m p u t e r or u s i n g f i n i t e
d i f f e r e n c e solutions of the d i f f e r e n t i a l s on a large
digital computer.
Continuous Systems Programming, General
P u r p o s e S i m u l a t i o n S y s t e m , o r D y n a m o II s i m u l a t i o n l a n g ­
u a g e s m a y b e u s e d to s i m p l i f y t h e p r o g r a m m i n g , T h i s m o d e l
f o l l o w s t h e f o r m a t of B r o w n (1968) , B o r a a s (1969) , B l e d s o e
and V a n D y n e (1969) , a n d S m i t h (1969) .

206

DOC
207

Model for Carbon-Flow in the Microplankton of a Lake at lm
r = respiration; d = death; k = active uptake; s = sedimentation;
e — excretion; p = passive diffusion.

208
I.

Algae:
1.

e i^ = e x c r e t o r y or

secretory

l os s o f D O C d u r i n g

photosynthesis.

Over a broad range

loss

fun c t i o n of the r a t e of p r i m a r y p r o -

is a l i n e a r

duction

(Anderson and

is a f u n c t i o n of a l g a l
log
where

a lg a e)
z

biomass

(Watt,

b(A)

k^A = primary production
= A'p*X0e

^ If

o

Dark

secretory

secretion

19 6 6) .
+ b(A)

is d a r k
hour

secretion.

^ = A

( P h o t o s y n ./ m g

2

_
—kz
,
= 1 e
g cal
o
^
I

1970).

secre t i o n = a log p r o d u c t i o n

a an d b a r e c o n s t a n t s ,

2.

_
= I

Zeutschell,

the rate of

= solar

N*V w h e r e
cm

—2

light

received

at a n y d e p t h

. —1
min

r a d i a t i o n at the

lake

p = c o n s t a n t of p h o t o s y n t h e s i s

surface

per unit

algal

biomass
k = c o e f f i c i e n t of

light

extinction

in w a t e r

z = depth
where N = n/n

max

= nutrient

coefficient

for

photosynthesis

there

is no e f f e c t

n = nutrient concentration
n

max

= nutrient c o n e . above which
on photosynthesis

where V = z^/z^ = mixing

at a m b i e n t

factor

for

light

light

intensity,

exposure

209
z^

=depth

of t he e u p h o t i c

z2

= d e p t h of a 0.02 d e n s i t y

zone
i n cr e as e

c o m p a r e d to

surface water
w h e r e A = b i o m a s s of a l g a e a nd p = p h o t o s y n t h e s i s per
u n i t a lg a l b i omass.
3.

r 2 *A

= algal respiration = A*RQ e

w h e r e A = b i o m a s s of

algae,

xT

e = b a s e of n a t u r a l

logs.
O
at 0 C

R q = r e s p i r a t i o n per u n i t b i o m a s s of a lg a e
e

xT

= e x p a n s i o n of
temp.

respiration

(T) of 0— 40°C.

in the r a n g e

of

If Q^g = 2 then

x =

0. 69.
However,
4.
DOC

r 2 *A =
d^-A

losses.

x k^ *A

in the p r e v i o u s work.

= d e a t h r a te of a l g a e - i m m e d i a t e a u t o l y t i c
This

is a lmost

independent parameters.

impossible

to e s t i m a t e

from

It c o u l d b e an i m p e r i c a l c o n ­

s t a n t X a l g a l b i o m a s s or by d i f f e r e n c e :
d, *A =
1
5.

(k.A - e ..A - e ~ A - r
+ P t A)
1
1
2
z
r2

e 2 *A = i m m e d i a t e a u t o l y s i s

of d e ad cells,

releas­

ing D O C = 1 0-30% o f the a l g a l c e l l c a rbon.
e 2 -A = 10 -30%

(k-jA - r &A - d ^ A - e-jA + p 2A)

210
6-

^2 *A = a -*-5a ^- u p t a k e of d i s s o l v e d

g e n e r a l l y by d i f f u s i o n
of D O C

(Allen,

organic

a n d t hu s p r o p o r t i o n a l

carbon;

to t h e c o n e .

1969a) .

p2*A = k^-DOC
w h e r e k, is t h e d i f f u s i o n c o n s t a n t ,
d
XI.

Bacteria:
1.

^ 2 * B = *3 a c t e r ial u p t a k e o f d i s s o l v e d

carbon compounds,

a first order uptake which

organic
is t e m p e r a t u r e

and nutrient dependent.
k

2

•B =

Z B*v

Kt2 (DOCi)B*exT -N
Z

O
1

Kt2 + (DOC±}
where
K^

2

DOC^

~

transport

for the

= c o n c e n t r a t i o n of t h e

B = bacterial
v■

constant

i

c e ll n u m b e r s

= v e l o c i t y of u p t a k e
106 bacteria

at

of

t

i*1*1 c o m p o u n d

compound
in n u m b e r s

the i t

compound

^

by

0 C.

yfp

e

X 10^ m l

4

= the t e m p e r a t u r e c o r r e c t i o n
u pt a k e ,
and T

in w h i c h x

is t h e temp,

for b a c t e r i a l

is a c o n s t a n t
O
in
C.

(near

0.069)

211
N - n/n

= nutrient

max

coefficient where

n — nutrient available

(inorganic).

nm a x = n u t ^ i e n t c o n c e n t r a t i o n a b o v e w h i c h
there

is no e f f e c t

on

t h e r a te o f

uptake.
2.

*c3 *b = b a c t e r i a l d e g r a d a t i o n

detrital

POC.

over

r a n g e us e d.

th e

This

is a l i n e a r

k ^ -B = w* POC *e

a nd

r e s p i r a t i o n of

function of temperature

xT

where
w

is a c o n s t a n t

for d e g r a d a t i o n o f

POC day

^

at 0°C.
In t h i s
POC/

its

photosyn.

admittedly

a crude

temperature
total

study

k ^ *PO C w a s

replacement

in it.

POC was d e g r a d e d

in t h e

3.
assumed

time

approximation

correction

= bacterial

the c o n c e n t r a t i o n
in d a y s .

but

it

No m o r e

of

This was

incorporated
than

65% of

the

epilimnion.

secretory

to be n e g l i g i b l e u n d e r

losses.

aerobic

These were

conditions

in t he

e p i l i m n i o n of l akes.
4.
system

rb*B = respiratory
is at

the

steady

l a t i o n of b a c t e r i a l

loss

state

from bacteria.

then

there

biomass compared

If t h e

is n o a c c u m u ­

to the

fl u x o f

212
organic carbon passing through

it.

equals

*B + k 3 *B, w h i c h m a k e s

the a c c r u a l

or equals

In g e n e r a l ,

t e m p e r a t u r e d e p e n d e n t and a f unction of
POC

it

size of the

standing crop.

III.

Dissolved Organic Carbon (DOC) :
1.

e^-A = algal

aCk ^ 'A )

secretion duringphotosynthesis

e^'A = algal

X algal

+ © 2 ^.

a u t o l y s i s u p o n ce l l

cell death where

This

is the c o m p l e x

independent parameters

3.

algal

death

kinetics.

4.
dation

its

exact

(see 1.5).

It h a s

t he

the

t

b

ith s u b s t r a t e .

assumed

formed

from d e g r a ­

It is t e m p e r a t u r e

to b e n e g l i g i b l e

in o l i g o t r o p h i c

lakewater.
5.
assumed
probably

e .•B = b a c t e r i a l
4

s e c r e t i o n or

to b e

in t h e

negligible

significant

See

form.

of d e a d p a r t i c u l a t e c a r b o n .
and

follows

form v =

e ^ ' P O C = l os s of P O C as D O C

dependent;

0.1 to

function not d e p e n d e n t u p o n

w h e r e S is t h e c o n c e n t r a t i o n of
for

=

cell d e a t h = d ^ A

^ 2 B = ^ a c t e r ^a l u p t a k e o f DOC w h i c h

first order

II.l.

=

+ b(A) see 1.1.

2.
0.3

the

this

fermentation;

e p ilimnion of

in t he h y p o l i m n i o n .

lakes,

213
6.

P 2 *^ = a l 9 a l h e t e r o t r o p h y ,

assumed
IV.

POC

1.

d ^ A = algal death;

2.

e ^ ’P O C = e x t r a c e l l u l a r

to D O C w i t h o u t

to be n e g l i g i b l e

nion.

in m o s t

k^'B = bacterial

and t h i s

of t he P O C
k

3

see

(POC) :
I.

4.

e n z y m a t i c d i g e s t i o n of

immediate uptake

H a l f t i m e of

1968,

kinetics;

to b e n e g l i g i b l e .

Particulate Organic Carbon

3.

zero o r d e r

Assumed

circumstances.
d i g e s t i o n o f PO C

this process

thesis).

by b a c t e r i a .

is

Imperically

in t h e e p i l i m —

3 5 — 60 d a y s
this w as

(Otsuki,
from

35-67%

formed or
*B =

.35 to

.67 X

photosynthetic

F O £ _------ 7—
replacement

where
photosynthetic

r eplacement time =

^___________________ POC______ _______________
p r i m a r y p r o d u c t . - . 3 OX p r i m a r y p r o d u c t
Upon

better

dependent

resolution this ma y

s a t u r a t i o n u pt a ke ,

l ar t o D O C u p t a k e .
4.

s ^ PO C

See

II.

a first-order

substrate

uptake

simi­

2.

= sedimentation

e p i l i m n i o n or d e p t h o f

be a t w o - s t e p

losses of POC

interest.

from

In p r a c t i c e

the

t h is w a s

---time

214
33-6 5% of t h e
Sj

(POC)

= net
s^POC

time.

POC

formed.

Over the

year

i nput of C 0 2~C f r o m t h e
=

the n e t

air.

. 33 - .6 5 X P O C / p h o t o s y n t h e t i c

replacement