E METAZOAN FAUNA

A SURVEY STUDY OF TH
05 MUD LAKE;

OF THE PSAMMOL‘TTORAL ZONE
BARRY COUNTY. MlCHlGAN

Thesis he fl» 599m af Hi. 5.
MWHBSAN STATE UNNEESQTY
Peter G‘ Weber
3963

 

THESIS

a
W *1 erv-v

 

 

 

 

L [B R A R Y 3
Mkiu'gzm State .
.— Unlucky

 

ABSTRACT

A SURVEY STUDY OF THE METAZOAN FAUNA OF THE
PSAMMOLITTORAL ZONE OF MUD LAKE,
BARRY COUNTY, MICHIGAN

by Peter G. Weber

Core samples were collected from the psammolittoral
zone of Mud Lake (T. 2 N., R. 9 w., S. 8, Barry County,
Michigan) from October 1961 to the end of August 1962
with the purpose of investigating the abundance and distri-
bution of psammolittoral organisms and their variance
throughout a season. Particular attention was focused on
the distribution of organisms--both vertical and horizontal——
within the psammon. Wherever possible correlations between
distributional patterns and physico chemical factors were
made.

The following physico chemical measurements were
taken: sand temperature, pH oxygen concentration, carbon
dioxide concentration, beach slope, and position of the
"black layer." Since the characteristics of these were
found to vary approximately in the same manner as found in
previous studies, an extensive discussion was not undertaken,

'but a listing of these characters for the Mud Lake psammon

is included.

Peter G. Weber

The composition of the Mud Lake flora and fauna was
approximately the same as that reported by Pennak (1940)
and Neel (1948) in their studies. A notable difference
between this and the two previously mentioned studies was
in the relatively meager rotifer fauna found in Mud Lake.
Cladocera, Malacostraca, and Acari were major taxons of
the Mud Lake sand which previously had not been reported from
the psammon. Other minor faunal differences were discussed
as well. The seasonal and spatial (vertical and horizontal)
distribution of the major taxons found in the sand was dis-

cussed and compared with that found by previous investigators.

A SURVEY STUDY OF THE METAZOAN FAUNA OF THE PSAMMOLITTORAL

ZONE OF MUD LAKE, BARRY COUNTY, MICHIGAN

BY

Peter G. Weber

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE

Department of Zoology
1963

(‘g :2 7 £0 r/ -/
- .1 If": ,r /

w] "i!"

ACKNOWLEDGMENTS

I wish to express my indebtedness to those who helped
with and gave suggestions to me during the course of this
project: Dr. T. W. Porter for his advice, criticism, and
encouragement; Dr. M. M. Hensley and Dr. J. E. Smith for
reading and criticizing the dissertation; Dr. H. C. Yeatman
for his work on the identification of the harpacticoid
copepods; Dr. R. P. Higgins for his identification of the
tardigrada; Mr. C. S. Scarborough for varification of the
mites. Also my gratitude is extended to Mrs. B. Henderson

for her aid in procuring materials necessary for this study.

11

TABLE OF CONTENTS

Page
LIST OF TABLES . . . . . . . . . . . . . . 1V
LIST OF FIGURES. . . . . . . . . . . . . . v
LIST OF PLATES . . . . . . . . . . . . . . vii
Chapter
I. INTRODUCTION . . . . . . . . 1
II. DESCRIPTION OF AREA STUDIED . . . . . . . 2
III. PROCEDURE . . . . . . . . . . . . . 4
IV. PHYSICAL CHARACTERS OF THE PSAMMON. . 7
Beach Slope . . . . . . . . . . . 7
Organic Debris . . . . . . . . . . 7
Temperature . . . . . . . . 2O
Hydrogen Ion Concentration . . . . . . 22
Carbon Dioxide Content. . . . . . . . 22
Oxygen Content . . . 22
Other Physico Chemical Characters Of the
Psammon . . . . . . . . . . . . 31
V. BIOLOGICAL ASPECTS OF THE PSAMMON . . . . . 32
General Features. . . . . . . . . 32
Faunal and Floral Lists . . . . . . . 39
Protozoan Distribution. . . . . . . . 48
Nematoda Distribution . . . . . . . . 57
Rotifera Distribution . . . . . . . . 6O
Tardigrada Distribution . . . . . . . 63
Oligochaeta Distribution . . . . . . . 65
Copepoda Distribution . . . . . . . . 73
Cladocera and Malacostraca . . . . . . 81
Larval Insect Distribution . . . . . . 82
Acari Distribution . . . . . . . . . 85
Other Metazoans . . . . . . . . . . 92
VI. SUMMARY. . . . . . . . . . . . . . 93
SELECTED REFERENCES . . . . . . . . . . . . 95

iii

Table

IO.
11.
12.
13.
14.

LIST OF TABLES

SlOpes of the three transects

Location of black layer; given (in cm.) as
(tOp figure in box) and
bottom figure

depth from tOp cm.
bottom limit of the layer (

in box)

Distribution of six groups of organisms in
relation to the black layer (black line)

for--

a. November 12, 1961 (T1)

b. October 28, 1961 éT3;
c. October 22, 1961

Air, water, and sand temperatures taken with a

T2

Weston thermometer.

pH of lake and capillary water taken with a

Beckman l8O pocket meter.

Chemical features of the Mud Lake capillary
water: 02, C02, and Alkalinity .

Distribution of testacious rhiZOpods.

Distribution
Distribution
Distribution
Distribution
Distribution
Distribution

Distribution

of
of
of
of
of
of

of

Nematodes
Rotifers.
Oligochaetes
tardigrades.
copepods.
immature insects

mites.

iv

Page

12

14
16
18

21

23

30
49
58
61
64
66
75
83
86

LIST OF FIGURES

Figure Page
1. Average height above water line on the three
transects, as determined from the slopes
taken with a Brenton compass . . . . . . 9
2. Horizontal variation in To ,T°s taken at depth

of 2. 5 cm. . . . . . . . . . . . . 24

3. Horizontal variation in T08 ; T0S taken at depth

of 8.0 cm. . . . . . . . . . . . 26

4. Horizontal variation in To ;T°S taken at depth
of 12.0 cm. . . . . . . . . . . . 28

5. Seasonal distribution of Algae, Testacia,
Rotifera, and Nematoda . . . . . . . . 35

6. Seasonal distribution of Copepods, oligochaetes,
insects, mites, and Cladocera. . . . . 37

7. Distribution of Algae (solid line) and fauna
(protozoa, Rotifera, and Nematoda; broken
line) on Transect 1. Total numbers of
organisms of the tOp 5 cm. . . . . . . 42

8. Distribution of Algae (solid line) and fauna
(protozoa, Rotifera, and Nematoda; broken
line) on Transect 2. Total numbers of
organisms of the tOp 5 cm. . . . . . . 44

9. Distribution of Algae (solid line) and fauna
(protozoa, Rotifera, and Nematoda; broken
line) on Transect 3. Total numbers of

organisms of the tOp 5 cm. . . . . . . 46
10. Horizontal distribution of testacious rhiZOpods

in the top 5 cm. of sand . . . . . . . 53
11. Vertical distribution of testacious rhiZOpods_ . 55

12. Horizontal distribution of Oligochaeta in the
top 5 cm. of sand. . . . . . . 69

Figure

13.
14.

15.
l6.

17.

Vertical distribution of testacious rhiZOpods.

Horizontal distribution of harpacticoid
COpepods in the top 5 cm. of sand.

Vertical distribution of harpacticoid copepods

Horizontal distribution of mites in the tOp
5 cm. of sand . . . . . . . . . .

Vertical distribution of mites.

vi

Page
71

77
79

88
89

LIST OF PLATES

Plate Page
1. Transect 1 on the eastern shore of Mud Lake . 11
2. Transect 2 on the southern shore of Mud Lake. 11
3. Transect 3 on the northern shore of Mud Lake. 11

vii

I. INTRODUCTION

The purpose of this study was to gain some insight
onto the kinds, numbers, and distribution of psammon
organisms and their variance throughout a season. Admittedly
studies of this sort have previously been undertaken and
therefore part of the initial purpose of the study was to
acquaint the author with the psammolittoral environment and
its organisms.

The psammolittoral region is one which investigators
have found to contain quite varied and extensive communities
of both plants and animals. Pennak (1940) concluded in his
study that "Perhaps no other environment is capable of
supporting such a dense and diversified group of microorganisms
as the sandy beach." This is also an environment which,
compared to other regions of the lake, has received relatively
little attention. Neel (1948) gave a brief review and an
extensive bibliography of the work done to 1948 and Pennak
(1940) also gave a good summary in his study. Except for
Myer's work, all of the fresh water psammolittoral studies in
this country have been undertaken in Wisconsin and Michigan.
The most recent work, by Neel (1948), stressed the physico
chemical aspects of the psammon in contrast to the emphasis
upon psammo organisms in previous studies. The present study
is concerned more with the biota of the psammon than with

its non-biological features.

II. DESCRIPTION OF AREA STUDIED‘

No previous study, limnological or otherwise, has
ever been undertaken on Mud Lake; consequently nothing is
known of either its biological or physico chemical character-
istics. The lake was selected for study primarily because
of its relative isolation. It is also one of the few lakes
in this particular area of Michigan with a natural sandy
beach relatively undisturbed by human inhabitants.

The psammolittoral region has been divided by several
workers into zones or sub-regions. Wiszniewski (in Neel,
1948) considered the psammolittoral to extend lakeward for
an indefinite distance and landward to a few meters above
the water—line; he divided this region into three general
areas:

1) hydrOpsammon: the Shoal portion of the sammon

(i. e. the submerged sand .

2) hygrOpsammon: the consistently moist region 0—1

meters above the water-line.

3) eupsammon : the most landward portion of the

psammon from 1—2 meters landward.
Though there are other ways of dividing the psammon, the
zonation of Wiszniewski is used throughout this paper since
it conveniently includes the entire psammolittoral zone;
other classifications being restricted to only the beach
portions.

Coarse sand, gravel, and an abundance of surface
vegetation characterized the Mud Lake psammon. According

to residents of the region the lake has been receding in

2

the past few years; the shoreward portion of the psammon

has thus been increasing in size and the shallows decreasing.
The width of the psammon varied but on the average was

eight meters. Collections were only taken from the lakeward
five meters of this region.

Three transects were arbitrarily selected, one on the
western shore (Tl), one on the southern (T2), and one on the
northern (T3) (see plates 1-3). Collections were made alternately
from each of the three transects throughout one year.

All three transects were overlaid by surface organic
debris expecially in the hydrOpsammon, as well as by a
considerable growth of surface Vegetation (mostly Scirpus

.gp. and Carex Sp.). The beach of both T1 and T2 was composed

 

of rather coarse sand grains and pebbles. The slopes of the
three beaches also differed (see Table 1).

On T1, the fine surface sand continued two meters
shoreward from the water-line and there was replaced by coarse
gravel and sand which extended landward for another four and
one half meters. Surface plants were found mostly in the gravel
region. T2 was distinguished by sand and gravel throughout
the entire beach region.

The psammolittoral zone was considered to extend
shoreward six meters from the water's edge and into the water
to where the layer of organic deposition replaced the sand.
The water-line was used as a reference point and designated
as 0, stations landward of the water-line were designated

as plus (+), and those shoalward as minus (-).

III. PROCEDURE

The methods employed for collecting and extracting

organisms were similar to those suggested in Limnological

 

Methods (Welch, 1948). Aluminum tubes of two-inch internal
diameter were inserted into the sand at 500m. intervals
along a transect on the beach. The tubes were inserted by
hand pressure to as great a depth as possible, which, in
most cases, was to about 15 cm. Immediately the tubes with
their sand core samples were stored upright in a portable
icebox and transported to the laboratory for processing.
Samples were refrigerated until processed. Collections were
made alternately from three different transects. In order
to get an estimate of seasonal variation in the fauna,
collections were made at monthly intervals except September
and those months when snow and frozen ground impeded field
work. Collections on a given transect were made within

50 cm. of each other so that subsequent samples were taken
from the same region.

The process of extracting the organisms from the sand
was that suggested by Welch (1948) and also used by Neel
(1948) in his study. A plunger was inserted into the lower
end of the aluminum tube, the sand core pushed out and divided
into one cc. sections from which the organisms were extracted.
The one cc. sand core was then placed into an evaporating
dish and one cc. of a saturated solution of menthol added as

a

U7

a relaxing agent. The sample was allowed to soak in the
menthol for five minutes after which 15 cc. of tap water
was added. A fine capillary stream of air was bubbled into
the evaporating dish bouncing the sand grains around and
separating out the organisms from the sand; this procedure
lasted two minutes. The water was then slowly decanted and
centrifuged for one minute and the super-natant again
poured back into the sample in the evaporating dish. The
entire procedure was repeated in the same manner three times
per one cc. sand sample. The material obtained from a one
cc. section of sand was then preserved in 16 cc. screwcap
vials in a solution of 40% glycerin in 4% formalin. Other
preservatives such as 4% formalin and FAA were tried but
the glycerin mixture was the best for taxonomic purposes.

Analyzation, counting and identification, of the
contents of the one cc. sand sample was done by shaking the
16 cc. vial to homogenize the concentrate thoroughly,
extracting one cc. with a drOpper and placing this in a
Sedwick-Rafter counting cell. The average from ten counts
was used to determine the number of organisms per cc. of
sand. In this manner an attempt was made to obtain an
estimate of vertical and horizontal as well as seasonal
distribution.

Due to the impracticability of such a large number
of samples it was not possible to make a second series of
ten counts which would have given greater accuracy to the

pOpulation estimates.

Because certain of the organisms (copepods, oligochaetes,
cladocerans, insects, and mites) were not present in sufficient
numbers to appear in the ten counts made with the Whipple
micrometer two different kinds of tabulations were made:

1) An estimate was taken with a Whipple micrometer
of the organisms present in sufficient number to
appear consistently in counts (these included
Testacea, algae, rotifers, nematodes, and tardigrades).
The average of ten counts from a one cc. Sedwick-
Rafter counting cell was taken and the number of
organisms per cc. of sand determined from this.

2) A second tally of the number of organisms per cc.
was taken by counting the total number of a particular
organism in the one cc. Sedwick-Rafter counting
cell; the number of organisms per CC. of sand were
determined from this.
Since the two counts were not equivalent there were no
comparisons made between them but they were instead treated

separately in the discussion.

IV. PHYSICAL CHARACTERS OF THE PSAMMON

Beach Slope

 

Measurements of lepe were made at 50 cm. intervals
along a transect with a Brunton compass. The importance of
the degree of slope in limiting the horizontal distribution
of psammo organisms was pointed out be Pennak (1940). In
general, the greater the slope the smaller the width of the
beach inhabited by psammo organisms. Greater SlOpeS do not
permit the movement of capillary water up the beach and in
these beaches there is a reduced quantity of capillary water
in the surface sand nearer the lake. Slope then, is a
primary factor in determining the distribution of capillary
water which, in turn, limits the distribution of psammolittoral
organisms.

Figure 1 shows the differences in the slopes of the

three transects.

Organic Debris

 

At depths of between 3-5 cm. below the surface there
was a stratum of organ material, the black layer (Table 2).
This layer, 4-6 cm. in thickness, extended vertically to a
maximum depth of 10-14 cm. below the surface. Occasionally
a sample would not Show a distinct black layer. Conversely,
a few samples contained a considerable amount of organic

material throughout most of their depth.

TABLE l.——SIOpes of the three transects at Mud Lake

 

 

 

 

Distance from Average Height
IIEGEeEeESIe (iilgggrees) Ab?i: Water-line
T1 T2 T3 Tl T2 T3
O (water—line) O 4 3

0.5 5 5 3 4.4 4.4 2.6
1-0 7 4 4 6.1 3.5 3.5
1.5 8 6 5 7.0 5.3 4.4
2.0 8 8 4 7.0 7.0 3.5
2.5 7 O 4 6.1 0.0 3.5
3.0 6 3 5 3 2.6
3.5 7 3 6.1 2.6
4.0 6 l 5.3 0.9
4.5 2 1.7
5.0 2 1.7
5 5 5 4.4

 

Figure 1. Average height above water-line on the three
transects. AS determined from the lepeS taken with a
Brunton compass.

a a. a a

0

if u e-

1.1839 Mint]. height shin Into-Jim (in a.)
v:

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no 150 zoo 8’0 300 350 A60 . 55b 560 556
W manta-u cap (in u.)

a; - --- ‘ - . Plate 1. Transect
’el; _ -‘*.S ,‘_,- ‘ ' p l on the eastern
IT‘jgji;—-- -_U- ,-. ’ shore of Mud
‘ "“ '* "5‘ ‘ ' Lake.

.
I .o 'v 1' u
. _:;" H;- ’f‘\t
.

 

Plate 2. Tran-
sect 2 on the
southern shore
of Mud Lake;
note the great
amount of sur-
face organic
matter in
hygrOpsammon.

‘(g-VI‘- )L;' 111'; ' f2?;":“ .. '

 

Plate 3. Transect
3 on northern
shore of Mud
Lake; note pro-
fuse surface
vegetation.

 

raw"

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,3;

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12

TABLE 2.--Location of the black layer given as depth

(in cm.) from the surface of sand; bottom figure in the
box is bottom limit of the black layer. Poorly developed
layer. Blank cells indicate absence of the black layer.¥

 

 

 

 

 

 

 

 

Distance From Water's Edge (in meters)

{-2 3 (+3 1
Date and transect 2 1.5 1 .5 O .5 1 1.5 -2--2.5 3 3.5 ‘2
Nov. 18, 1961 1. a 3 4 4 3.5 5 ' 5 3 ~ 4
7 11 10 6 11 8 7 9

Oct. 22, 1961 2. 3 6

* -)(- * 9 * * * 9
Oct. 28, 1961 3. 5 9 5 8 4 4 3 5
lo 14 9 12 10 8 7 10
Nov. 12, 1961 1. 4 4 4 4 3 4 8 4
11 8 12 13 9 5 14 * * 10
Dec. 3, 1961 2. 4 3 - 4 3 3
* * 12 8 x 6 * 9 9

 

 

 

 

*Asterisks indicate presence of black layer but no distinct
upper or lower limits.

13

According to Neel (1948) and others, ". . . the black
layer is due to the reduction of iron oxides by sulfides pro—
duced by anaerobic decomposition of organic material," and
that ". . . color changes associated with penetration of
oxygen into black sand indicate that the upper limit of the
black layer marks the division between anaerobic and aerobic

zones in the sand."

Very few organisms occurred below 2—3 cm.,
and, apparently the black layer may be a major limiting

factor in restricting the vertical occurrence of the psam-
mobiota. Table 3 graphically demonstrates the distribution

of some of the psammoorganisms in relation to the black layer
on the three transects at a particular time. In every
instance, except the oligochaetes which are highly motile,
there were no organisms found below this layer. Certain

other factors, aside from the black 1ayer,such as the amount

of oxygen and light, the latter of which particularily restricts
the algal flora to a depth of 2-3 cm. , were factors limiting
the vertical distribution. Since in transects where the

black layer was poorly develOped organisms did not occur to
depths greater than in the transects with a well develOped
stratum, the exact importance of the black layer was impossible
to evaluate in comparison to other factors (e. g. amount of

light, water, etc.) in restricting the depth to which psammo

organisms occur.

14

 

 

 

 

 

 

 

 

 

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20

Temperature

 

Sand temperatures (Tg) were taken at 2.5, 8, and 12 cm.

below the surface of the sand. AS seen from the temperature
graphs (Figs. 1-3), there was a considerable horizontal
variation along the psammon, eSpecially in the tOp 2.5 cm.
and at the higher sand temperatures (e. g. Fig. 1, June,
July, October 18 and 22). At lower T3 and greater depths
(8, 12 cm.) the T3 differences between readings horizontally
along the psammon were not as great as at lesser depths

(i. e. 2.5 cm.) or at higher T2. Rain also tended to cause
the T: to flatten out. Pennak (1940) found the surface
temperatures between the (+) 0.5-2.5 meter stations to be
fairly homogeneous with rarely a difference greater than
2.5° C between any two horizontal readings. This he
attributed to the influence of the capillary water in this
region. In the present study such homogeneity in surface

T: was found at the lower but not higher sand temperatures,
though the differences between any two temperature readings
even at the higher temperatures were slight.

Vertically the mean T: for the entire psammon decreased
with depth. In one instance the T: remained the same from
2.5—l2 cm. and in two cases it increased very slightly
(Table 3).

Pennak (1940) enumerated the following factors which

in combination in general determined sand temperatures:

l7

 

 

 

 

 

 

 

 

 

 

 

 

 

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TABLE 4.-—Air, water, and sand temperature (Tos) taken
with a Weston thermometer.

 

 

 

 

 

 

Sand
Distance
Beach and Date Air Water (-)
Weather and Tem . Tem . Depth '
Conditions Transect (C°) (0°) (cm.) 2 l .5

Waves chOppy Oct. l8, 18 16.5 2.5 l7 l7

onshore, 1961 8.0 15 16

weather clear 1. 12.0 l5 15
Beach moist Nov. 12, 10 8.5 2.5
throughout 1961 8.0
overcast 1. 12.0
Apr. 7, 7 6 2.5
1962 8.0
2. 12.0
Waves mild June 25, 29 31 2.5
onshore 1962 8.0
clear 1. 12.0
No wave Oct. 22, l4 14 2.5
action 1961 8.0
clear 2. 12.0
Beach moist Dec. 3, 10 6.5 2.5
clear; some 1961 8.0
ice on lake 2. 12.0
Waves strong July 27, —— -— 2.5
onshore 1962 8.0
clear 2. 12.0
Waves onshore Oct. 28, 9 10 2.5
chOppy, over- 1961 8.0
cast, wet 3. 12.0
Waves mild, May 1, l3 18 2.5
parallel to 1962 8.0
Shore, rain 3. 12.0

 

 

 

 

 

Temperature (C°)

 

from Water's Edge (in meters)

 

 

 

(+I' ‘" 33
1 5 o 5 1 1 5 2 2 5 3 3 5 Y
17 5 17 16 18 19 19 18.5 17.5
17 16 15 17 17 16 1 16.0
14 5 15 14 15 15 15 16 15.0
8 5 8.5 9 9 9 9 9.5 .0
8 8 8.5 8.5 9 9 9 9 8.5
8 8.5 8.5 8 5 8.5 8.5 8.5 8.5
5.5 5 5 5 5.5 5.0
5.5 5 5 5 5.5 5.0
5.5 5 5 5 5.5 5.0
30 31 31 31 34 36 36 32.5
28 28 29.5 29.5 30 33 33 30.0
26 26 27 28 27 31 30 28.0
14.5 15 17.5 15 14 15 14 14 5 15.0
14 14.5 15 14.5 14 15 14 14 5 14.0
14 14 15 13.5 13 14 13 14 14.0
7 8 8 7 7 7.5 8’ 7 8 7.5
6 7 6 5.5 6 6 6 5 6 6.0
6 6.5 5 4 4 5 5 4 5 6 5.0
26 26 22 23 23 25 25 29 25.0
25 25 23 24 24 24 25 27 25.0
24 24 22 23 22 22 23 24 23.0
8.5 8.5 8.5 8.5 8.5
9 8.5 8.5 8.5 8.5
9 9.5 8.5 8.5 9.0
17 14 14 14 14 14 14.5 15 14.5
17 16 16 16 15.5 15 15.5 15 - 15.5
16 16 l6 16 15.5 15.5 15 15 15.0

 

 

 

22

lake water temperature, air temperature, amount of
capillary water in the sand and its evaporation, wind, rain,
and sunshine.” According to Neel (1948) isolation and lake
temperature affect the shoal portions of the sand exclusively.
Previous workers have studied the T: extensively and it is
not the purpose of this paper to indulge in a discussion of

sand temperature characteristics.

Hydrogen Ion Concentration

 

Table 5 shows pH determinations taken with a Beckman
pocket 180 meter. The data indicates that the acidity
increased shorewards. This agrees with the findings of others
(Pennak, 1940; Neel, 1948). Lake pH and capillary water
pH were much alike though in every case the interstitial
water of the most shoreward station sampled (+1M.) was more

acid than the lake water.

Carbon Dioxide Content

As shown in Table 6 the amount of free C02 was higher

 

in the landward station than in the lake. Likewise, the
bound C02, as expressed by the methyl orange (M. O.)
alkalinity, also increased. No phenolphthalein alkalinity

was obtained

Oxygen Content

Determinations of the oxygen concentration were made
by means of the Ridal-Steward modification of the Winkler

method.

20

Temperature

 

Sand temperatures (T3) were taken at 2.5, 8, and 12 cm.
below the surface of the sand. As seen from the temperature
graphs (Figs. 1—3), there was a considerable horizontal
variation along the psammon, especially in the tOp 2.5 cm.
and at the higher sand temperatures (e. g. Fig. 1, June,
July, October 18 and 22). At lower T8 and greater depths
(8, 12 cm.) the Tg differences between readings horizontally
along the psammon were not as great as at lesser depths
(i. e. 2.5 cm.) or at higher T2. Rain also tended to cause
the T: to flatten out. Pennak (1940) found the surface
temperatures between the (+) 0.5—2.5 meter stations to be
fairly homogeneous with rarely a difference greater than
2.5° C between any two horizontal readings. This he
attributed to the influence of the capillary water in this
region. In the present study such homogeneity in surface
T: was found at the lower but not higher sand temperatures,
though the differences between any two temperature readings
even at the higher temperatures were slight.

Vertically the mean T: for the entire psammon decreased
with depth. In one instance the T: remained the same from
2.5-12 cm. and in two cases it increased very slightly
(Table 3).

Pennak (1940) enumerated the following factors Which

in combination in general determined sand temperatures:

24

Figure 2. Horizontal variation in sand temperature. Temper—
ature taken at depth of 2.5 cm.

 

Temperature (C°)

 

from Water's Edge (in meters)

 

 

 

(+7’ .ii
1 5 0 5 l 1 5 2 2 5 3 3 5 'Y
17 5 17 16 18 19 19 1 .5 17.5
17 16 15 17 17 16 18 16.0
14 5 15 14 15 15 15 16 15.0
8 5 8.5 9 9 9 9 9.5 .0
8 8 8.5 8.5 9 9 9 9 8.5
8 8.5 8.5 8 5 8.5 8.5 .5 8.5
5'5 5 5 5 505 500
5.5 5 5 5 5.5 5.0
5.5 5 5 5 5.5 5.0
30 31 31 31 34 36 36 32.5
28 28 29.5 29.5 30 33 33 30.0
26 26 27 28 27 31 30 28.0
14.5 15 17.5 15 14 15 14 14.5 15.0
14 14.5 15 14.5 14 15 14 14.5 14.0
14 14 15 13.5 13 14 13 14 14.0
7 8 8 7 7 7 5 8" 7 8 7.5
6 7 6 5 5 6 6 6 5.5 6 6.0
6 6 5 5 4 4 5 5 4.5 6 5.0
26 26 22 23 23 25 25 29 25.0
25 25 23 24 24 24 25 27 25.0
24. 24. 22 23 22 22 23 24 23.0
8.5 8.5 8.5 8.5 8.5
9 8.5 8.5 8.5 8.5
9 9.5 8.5 8.5 9.0
17 14 14 14 14 14 14.5 15 14.5
17 16 16 16 15.5 15 15.5 15 ‘ 15.5
16 16 16 16 15.5 15.5 15 15 15.0

 

 

 

Ill ‘l‘fi EILl.ful\flI-OI .l..ll .(Il..rfl.

 

 

 

 

 

 

 

c.» c.w H.s H.w H.» me .HcmH
um oOWQ
o.e H.s H.s H.e H.» He .HcmH
qme .>02
33 m.c H.n H.s H.s m.s HE .HcmH
2 “H .>cz
m.o 0.0 o.s o.s 0.» me .HcmH
.sH .wse
m m.H H, m. o m. 2m. A-V on comments
H+p HIV dong mm ome 02m coma
AmepoE :HV mmcm m_Hop63 Eopm oocmpmHo
AmQHoHooos m Ho ommpo>mv
.80 3 mo comma m pm memB mm Hmpmz HHmHHHmwo
.HouoE ma poxooo cmH
cmEXOOm w csz Coxmp Hops: kaHHHQmo ccm owa co mo::.m MHm<B

24

Figure 2. Horizontal variation in sand temperature. Temper-
ature taken at depth of 2.5 cm.

Tbmperature (Co)

36

34

32

28

26

24

22

2O

18

l6

l4

12

10

 

r»——_n—a””*‘-n

  

25 Jun 25, 1962 T1

Jul 27, 1962 T2

Oct 18, 1961 T1

 

Oct 22, 1961 T1
+

fl /D—"-*May 1, 1962 T2

Nov 12, 1961 T1

\
W Oct 28, 1961 T3

 

Hfl—H—fi Dec 3, 1961 T2

4) Apr 7, 1962 T1

 

T

I

r

 

T I t I I I

2.0 1.5 1.0 0.5 0 0.5 1.0 1.5 2.0 2.5 3.0 3J5 4.0

(~)

(+)

Distance from water's edge (in M)

26

Figure 3. Horizontal variation in sand temperature. Temper-
ature taken at depth of 8 cm.

Thwperature (Co)

34

32

28

26

24

22

2O

18

 

 

27

Jun 25, 1962 T1

Oct 18, 1961 T1

 

Ha I, 1962 T3
Oct 22, 1961 T2

.. .:--Wr--1; Nov 12, 1961 T1
.E'HH4§:=’1F=::3::::;. Oct 28, 1961 T5
._—/

 

8* I‘?‘-.K Dec 3, 1961 T2

I“‘~1-———1-———€"”( Apr 7, 1962 T1

 

2.0 1E5) 120 0:5

 

0 0:5 1:0 115 220 2.5 310 5.5 410
+

Distance from water's edge (in I)

28

Figure 4. Horizontal variation in sand temperature. Temp-
erature taken at depth of 22 cm.

Tameramro (Co)

34

32

30

28

26

24

22

2O

18

16

14

12

10

 

L.

29

 

 

 

 

Jun 25, 1962
T1

Jul 27,1962
T2

1, 1962
18, 1961

22, 1961
28, 1961
12, 1961

7, 1962
3, 1961

 

wI ‘ I
2.0 1.5( 1.0 005

(+)
Distance from water's edge (in M)

0 0:5 1:0 I.5 2.0 2.5 3.0 3.5 4.0

 

3O

 

 

 

 

o.o omH m.om o.o Em. H+V

cm 0.0 mmH c.m o.m go mg
6.0 mmH 6.: c.e Em. H-v mc-Hm-m
o.o mcH m.mm s.H Em. H+V

Hm o.o omH e.e m.: 56 mg
6.6 moH e.m m.m am. H-v Hc-eH-w

oov H.eoov . H.eaov Eddy H.2nov . coHooem permeate

. ace eHstHa ce-cm aHHesHs .o .z oo cote somsxo one open
.Ammchmos 03p EOHH omwao>m onpvhuHcHwaH< ocmwmcc .mc

”Hoods mHeHHHQmo owa o5: ecu mo moHSHmom HmoHEwncun.m mqm<e

31

The oxygen concentration decreased landward"(Table 6),
the concentration in the shoal stations being considerably
higher than that of the beach stations. All previous
investigators have reported such a shoreward gradient of

oxygen.

Other Physico Chemical Characters of the Psammon

Light, grade distribution of sand, pore Space, wave
action, and interstitial organic matter are other known
factors affecting the distribution and population size of
psammon organisms. Due to the limited SCOpe of this investi—
gation the measurement of the above mentioned factors was
not undertaken. Previous papers of Bruce (1928), Pennak
(1940), and Neel (1948) investigating the psammon, and in
particular the non-biological characteristics, discuss these
points in some detail.

The major problem in determining the chemistry of
interstitial water is first, the amount of this water is
very small, and secondly, water is quite difficult to
sample at given vertical levels in the sand with any degree
of accuracy. A modified Irwin sampler as used by Neel (1948)
was employed to extract the water. Capillary water was
always taken from a depth of four cm. Beyond (+) 1.5 meters,
however, water could not be drawn in sufficient quantities to
make the necessary determinations, and even at (4) 1 meter
it was difficult to extract water without a considerable

amount of air being taken up at the same time.

V. BIOLOGICAL ASPECTS OF THE PSAMMON

General Features

 

The horizontal distribution of organisms* along
the psammon exibited approximately the same pattern on each
of the three transects (Figs. 7-9): high numbers of
both algae and microfauna in the (+) .5 to 2.5m region of
the beach whereas the hydro-psammon, (O to (-) 1.5m) con-
tained a relatively meager fauna and flora; the shoreward
region beyond the meters contained few organisms.

POpulation peaks in the horizontal distribution of
algae did not necessarily imply correlating peaks in the
microfaunal (Testacea, Nematoda, Rotifera, and Tardigrada)
populations (Figs. 7-9),. One might expect somewhat of a
correlation here since the majority of psammo—organisms are
herbivores or bacterial feeders.

A more detailed description of the spatial as well
as the seasonal distribution of the various psammon groups
will be undertaken in the discussion of the individual

taxons.

 

*Organisms in this instance refers to only the following:
algae, Testacea, nematodes, tardigrades, and rotifers, all
of which were estimated in a slightly different manner from
the larger sammomicroorganisms (e. g. COpepoda and
Oligochaeta)

32

33

Algae were identified to genus with the exception of
diatoms. Two kinds of counts were taken of the diatoms:
one estimate of the total number of fustules and a second
of just those fustules with chlorOplasts. The diatom count
was extremely high when one considered the total number of

fustules per 00. However, the count became smaller than the
blue—greencncgreen algal estimates when only fustules with
chlorOplasts were included. Other investigators, Pennak
(1940) and Neel (1948), have found diatoms to be the most
abundant psammon algal group. Their estimates--if based
upon the total number of fustules--would be too high and

thus misleading. Large numbers of filamentous CyanOphyta

(mostly Lyngbya Sp. and Oxcillatoria Sp.)_appeared at

 

certain times in some of the transects; Merismepedium sp.

 

was the only other blue-green alga of common occurrence.
The green algal flora was represented by a greater number
of genera but not by as many individuals as the diatom or
CyanOphyta groups. The most abundant of the ChlorOphyta

were Cylindrocystis sp., Netrium sp., and Cosmarium sp;

 

 

very few filamentous ChlorOphyta occurred in the Mud Lake
psammon. The EuglenOphyta, though not Often found in the
counts of preserved material, were suspected, on the basis
of preliminary observations of ”live sand" samples, to be
abundant in the psammon.

Seasonally, excepting December and April when pOpula-

tions were low, the algae as a group exibited no consistent

34

pOpulation fluctuations or patterns (Fig. 4). The CyanOphyta
- were most abundant in October and May and at low numbers
during June, July, April, and December. The ChlorOphyta,
conversely, were at a peak during May, June, July, November,
and portions of October but at relatively low numbers during
December and April. Paradoxically large algal populations
appeared in May during which the psammo-microorganisms were

at the lowest numbers.

35

Figure 5. Seasonal distribution of algae, testaceous
protozoa, rotifers, and nematodes.

nu Ha ma Ha ma Hy ma ma Hy
Rb?» amass H3. eHHhH «8898 $88.26: 8.888 «machete 2.2338

 

33%.: n
«.538 a
88...er tfloa
«Hedda s
nflflbfixflhoonu
58.2 a
dizzija.flflbh_m
Srgtaom
genuine D
Sundanese I

 

 

 

 

 

'00 Jed smsIueBJo JO Jeqwnm

pues jo

37

Figure 6. Seasonal distribution of COpepods, oligochaetes,
insects, mites, and Cladocera.

EN 5D mo. 83.

H N3 H m Amer 0mm NH ponso>oz mm Henopoc

 

 

 

38

 

 

1111
[111111]

‘1]

 

 

 

auuooeaHo mm

neaHsimw

daooncHMWW

qegsnxnzuo Hears a:
3.8835 essences M
H.eonenooc aoHooHaosnnau mu
HSoSoSHHoc 321a I

 

 

 

 

 

Es

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

me Erato

.u «n

ma Hononoo

 

 

 

m

 

 

 

 

 

 

 

 

 

 

 

HoeH
own
.63

.080

8
«>
put 9 JO oo /8WBTUBBJD Jo Jeqwnu

.cco

.ONHH

rcmNH..

. 6.3

TOOQH

.cch

.cme

Axxxw

 

 

39

Faunal and Floral Lists

Floral Lists

I. ChlorOphyta

O:

Chlorococcales
Pediastrum Sp.

 

Sorastrum sp.
Quadrigula sp.
Scenedesmus sp.

 

 

 

Zygnematales
Mougeota Sp.

Netrium Sp.
Closterium Sp.

 

Cylindrocystis Sp.
Tetmemorus sp.
Staurastrum Sp.

 

 

 

Euastrum Sp.
Micrasterias Sp.

 

Cosmarium sp.

 

Spirogyra Sp.

 

Micricystls Sp.

 

Zygnema Sp.
Gomphosphera Sp.
Synecocooccus sp.

 

 

II. EuglenOphyta

O:

Euglenales

Euglena sp.

III. Chrysophyta

IV. CyanOphyta

O:

Faunal Lists

Chroococcales
Merismepedium Sp.
Gloeocystis sp.

 

 

Oscillatoriales
Oscillatoria sp.

Lyngbya Sp.

 

I. Protozoa

O:

Testacealobosa

Arcella vulgaris Ehrenberg

A. discoides Ehrenberg
Centropyxis aculeata (Ehr.) Stein

 

 

 

40

C. constricta (Ehr.) Penard
C. arcelloides Penard

C. ecornis (Ehr.) Leidy
Difflugia urceolata Carter
D. lebes Penard

D. corona Wallich

D. lobostoma Leidy

D. oblonga Ehrenberg
Hyalosphenia elegans Leidy
Qualdrulella Sp.

Nebela Sp.

Cyphoderia Sp.

Euglypha cristata Leidy

Euglypha Sp.
II. Turbellaria

 

 

 

 

 

 

 

 

 

 

 

III. Nematoda
IV. Gastrotricha

V. Rotifera
O: Bdelloida
Philodinidae

O: Ploima
Keratella cochlearis
Kellocottia sp.
Trichocerca sp.
Colurella Sp.
Lecane muoronata
Lecane sp.
Monostyla sp.

 

 

 

 

 

 

VI. Tardigrada
O: Eutardigrada
Macrobiotus dispar Murray
Hypsibius granulifer (Thulin) Marcus

 

 

VII. Annelida
O: PlesiOpora
Aeblosoma sp.
Stylaria Sp.
Chaetogaster Sp.
Pristina osborni (Walton)
P. breviseta (Bourne)

 

 

 

 

VIII. ArthrOpoda
O: Cladocera

O: Malacostraca
Hyalella azteca (Saussure)

 

41

Copepoda

Pastenocaris brevipes Kessler

P. delameri Chappius

Elaphoidella bidens coronata (Sars)

 

 

. Insecta
O: Collembola
Pondura aquatica (L.)

 

Diptera

F: Tentapedidae

F: Delicapodidae
F: Chaeronomidae

Acari
Oribatidae

42

Figure 7. Horizontal distribution of algae (solid line)
and the combined pOpulations of Protozoa, Rotifera,
Nematoda, and Tardigrada, in transect 1. Total numbers
of organisms in the tOp six cc.

 

lmnboroforganimintwoinomofoand

530,000
600,000
570,000
540,000
420,000
390,000
360,000
330.000
300,000
270,000
240,000
210,000
180,000
150,000
120,000

90,000

60,000

30,000
15,000

x4++ n

A

 

I

43

)—-— 1001’. 18.1961
.— —0N0v 12,1961
—--®Jun625, 1962
lI----lNov 12,1961

”DOOt 18,1961
[bx-EJ131925, 1962

 

 

i...

 

 

T
1.5 %.<)J 0.5 0 0.5 1(0) 15 20 2.5 3.0 3.5 40

Distance from water' a edge (in M)

44

Figure 8. Horizontal distribution of algae (solid line)
and the combined pOpulations of Protozoa, Rotifera,

Nematoda, and Tardigrada in transect 2. Total numbers
of organisms in the t0p six cc.

Hmflnu-ofcngpnhmusiniup Ehreo.¢flfa&md

142,500 4

 
 
   
  
  

135.000 4 'i
‘ T n
J
1 o b-Dfl'30ct 22' 1961
27'50 ‘ o—--—onec 3, 1961
«"h—“Jul 27, 1962
120,000 4 !---lJu1 27, 1962
LIN-"[1001? 22, 1961
lv—X-IJDeo 3, 1961
112,500 ‘

105,000
97.500 ‘
90,000 .
32,500
75,000 -
67.500
60,000

52.500 .

 

45,000

 

37. 500

 

 

30,000 «
22,500 '2

15,000

 

 

7.500

3.750 s n

 

 

6.5 120 115,210 2.5 5.0 5.5 Lo
‘0

 

Distance from water's edge (in M)

46

Figure 9. Horizontal distribution of algae (solid line)
and the combined pOpulations of Protozoa, Rotifera,
Nematoda, and Tardigrada in transect 3. Total numbers
of organisms in the tOp Six cc.

Number of organisms in top 311 cc. of sand

 

 

47

./

 

 

 

 

 

(+)

o—--o Oct. 28,1961
1 ---- Hay' 1,1962
I - ~-l0ct. 28,1961

\

.. /_-'

’1 - _TI-;|-/“
cf 015 1.0 125 210 23

3:0 3.5 #10

Distance from water's edge (in II)

48'

Protozoan Distribution.

 

Because of the fact that all protozoans except the
testaceous rhiZOpods were too fragile to survive the particu—
lar treatment used for extracting psammon organisms, the
following discussion includes only the latter. However, in
the preliminary observations of ”live" sand samples, a
considerable protozoan fauna was noticed, eSpecially of the
Ciliata (e. g. Hypotricha and Holotricha) and MastigOphora
groups. Previous studies, for the reason given here, also
have included only a discussion of the Testacea; a thorough
ecological study of psammon protozoa is thus needed although
a major problem of extracting these organisms exists.

The genus CentrOpyxus sp. was, by and large, the most

 

abundant of the Testacea in the Mud Lake psammon. Considerable

pOpulations of both Arcella sp. and Difflugia Sp. were also

 

present in some collections. Centropyxis aculeata (Ehrenberg)

 

Stein was the common species of this genus; though_g;

constricta (Ehr.) Penard was also present in some numbers.

 

 

Euglypha sp., Hyalosphenia sp., Quadrulella sp., Cyphoderia

 

 

sp., and Nebela sp. were other genera of Testacea which
occurred in small numbers in the sand.

Horizontal distribution: As seen from Fig. 9 the great-
est concentration of Testacea was in the landward portions
of the beach between (+) 0.5 and 2.5 m. This roughly concurred

with Pennak's (1940) findings. In contrast to the horizontal

49

 

 

 

 

H .H
* oomH m mmmH
* oozo m .H HHpo<
oomm * oomm oomm H
oooH H H
oow: * oooH * m HomH
oozo ooHo oozo oomm oom: * m .mH .>oz
oooo oooo ooom oom: oozo oozo * * * H
* NH
HH
oH
o
1.. m
s
o
* m
oozo * oooH H .H
oom: oommH oooH oooH oooH m HomH
oomo oomom oozo oooH * * oomm m .mH .poo
ooooH ooom oooH ooom oooo oooH oooH H
m;w m m.N N m.H H m. 0 m. H m.H N A.EOV Pcmmfimfip
H1O A-v spoon one oomo

 

69$me 93. ompm m Loom: 509m o.oca-p.mHm

 

 

 

l‘

__. mdonNHoE. .msooomumu

u0.moHu5

 

mHgomHmn-.H mqm<a

50

 

 

 

 

 

. oowH * o
oomH oomH * * m .m
oowH oomm * * H HmmH
oowH oooH * * * oomm m .m .ooo
oomm * oom: ooHo oooH oomm * m
ooow oom: ooon oowH oomH oomm H
com: o
oooH comm m .m
comm oomH * * : HmmH
oomm oooH * oooH * * m .mm .Hoo
* comm * * * * OowH m
oooH ooomm oomm oomH o * oomm H
oooH o
m .H
* : mmmH
oomm oooH m .mm onus
* oomHH oom: oomm * m
oooH ooow * oome oomH oooH H
mlm m m.N N min H m. 0 H mtm N AHQOV ”10meth
H+V H-V spoon one moon
Ampopoe :HV mwpm n.90pw3 Boom mocmpmHQ

 

 

 

 

 

 

HooooHpcoov--.s mHmoa

 

51

 

 

 

 

 

 

 

o
ooon * . m .m
ooom oooH * H momH
ooow oomm * * m H Hm:
oooH oooH oomHH * ooHo * m
oooH oomH oomH oomm ooHo oomH oomH oomHH H
oowH w
* * N.
* * @
ooHo m .m
* 00mm H HmmH
oooH oomm oomH oomm oowm * oompm m .wm .ooo
oomH * oomH oooH * ooow * m
ooom oomm * oomH ooos ooooH oomm * H
o
* m
oooH oomm H
oooH oomm * m .m
oooo ooHo oomm oooH oooH * * m mooH
ooow oomoH ooHom ooow ooom oomH oomH oomm oomm ooHo H .em HHHH
3 m.m m m.N N m.H H m. 0 m. H m.H N A.Eov vommghfl
H+H¢ . HAHI spoon ooo opmo
AmhopoE :HV owom m.Hmpw3 Eopm mocmpmHm

 

 

 

HooHoHpooov--.H mHmHB

52

distribution of oligochaetes and COpepOdS, the distribution
of Testacea seemed to be generally characterized by more
than one peak and by a fairly stable population throughout
each transect. Vertical distribution: Most Testacea were
found in the t0p centimeter of sand, their numbers rapidly
decreasing below this level in virtually every transect
(Fig. 10). Tests were found to a depth of 12 cm. However,
Since one cannot determine from a test whether the animal
had been alive or not, one cannot be certain that living
testacea wandered to this depth.

Seasonal distribution: The testaceous rhiZOpods were in
general most abundant in the October (T1, 2, 3) collections
and least abundant in the April samples. High numbers of

a particular group in one portion of the beach at one season
did not necessarily mean high numbers of the same group

in other portions of the beach (e. g. Arcella sp. pop-
ulations for October varied considerably between Tl, 2, 3).
Also, high numbers of a particular genus at one time did not
necessarily mean correSpondingly high numbers of other
Testacea in a particular transect.

CentrOpyxis sp. consistently appeared as one of the

 

more abundant of the Testacea on nearly every transect and
at virtually all times. Populations of this genus remained
fairly stable throughout the season compared to the variance
in numbers of the other common Testacea (Fig. 4). Peak

Centropyxis Sp. pOpulations occurred in the October 18,

 

Figure 10. Horizontal distribution of testaceous
rhiZOpods in the tOp five cc of sand.

 

 

54

 

 

 

 

 

 

 

67.500
Oct 18 1961 T1
63.750 4 3,. -m', Nov 12: 1961 T1
2 “*2“: 2922 ..
Er- c-J c 9 T2
60.000 ‘ 2.0-1.. Dec 3: 1961 22
+ 2...... 22 22 ..
‘ ® """ 90 c 1 T3
56.250 m-x x—M-iay 1: 1962 '13
52.500
48,750 .
J
45,000 )
1341.250
S
Cd 4
(D
9437.500 1
O J @
833.750 1
s. 4 a
a, ..
Q30,000 . "
(I)
E
m o
' "(5326.250 1 '
.0 7 '. .'
‘5 .
“22,500 .
o . ,'
$180750 J '
Q o
5 J . '
z15,000 . '.
1 '-
11,250
.5:
7,500 . "2': . .
‘\ A o :.R O
3.750 ‘ .1 ’x
1 8 , .\I I
.75 L 7‘ - X , - - .
1.5 1.0 0.5 6 0.5 1.0125) 2.0 2.5 3.0 3.5 4.0
- 0

T1qt2nn.: Prnm wzta.-‘a pflon (in m\

Figure ll.

55

Vertical distribution of testaceous rhiZOpods.

97,400
93.650
89,900

86,250

56.250
52,500
48,750

45,000

b
H
[0
$3

of sand

Number of organisms per cc.

15,000

11,250 *

7.500 ‘

3.750
1,895

 

 

 

 

16,750 ‘

 

 

 

56

Vertical distance (in an)

Oct
Nov
Jun
Oct
Jul
Dec
Oct
Kay

1961
1961
1962
1961
1962
1961
1961
1962

fin3t3

T2

T2
T3
T3

15

57

October 22, and July 27 collections while the low numbers
were found in the December 3 and April 7 collections.
Arcella Sp. was found in the highest numbers in October 18
but decreased in subsequent collections to a low in Novem—
ber and December; there was then a slow increase in numbers
in April, May, and June to again a maximum in July.

Difflugia sp., excepting a pOpulation high in the October

 

collection, remained at fairly low numbers (absence from
the graph does not indicate absence of an organism from the
sand but, rather, that its numbers were too few to Show

up in the count). Other Testacea (including a considerable
number of Euglypha sp. and individuals of the genera
HyaIOSphaenia sp., Quadrulella sp., and Cyphoderia sp.)

 

 

were present in low numbers in October 18 and 22 but reached
higher population levels in succeeding collections. Few of
the last mentioned genera were found in the April collection,
their numbers increased in the May, June, and July collections

(Fig. 4).

Nematoda Distribution

 

POpulations of this phylum remained fairly stable
in the psammon, and, though widespread, nematodes were
never present in sufficient numbers within any one transect
to graph distributional tendencies. Nematodes were found
horizontally along the entire psammon and, as in Pennak

(1940) the greatest numbers occurred in the hygro- and

58

 

 

 

 

* cowH * * * m .m
* * * * * H HmmH
comm * * cowH * * m «mm .900
* oowH * * * * cccH m
* * * * comH H
* m
* m .H
H HmmH
* * m .mm 0::h
* ccmH * * m
ccmH * * * ccwH H
H .H
* m momH
* * * m .n HHHQH
ccmH * * H
H .H
* * * m mmmH
* oooH * 2 m .mH .>oz
* * * * H
H .H
* * * * * * * m HmmH
* * * * oooH * m .mH .ooo
* * * * * H
m.m m.m m m.H H m. o m. H m.H m A.Eov pommcmpp
H+c H-c spoon one moon

 

Amhopoe :Hv owom m.moumz Eomm ooCmpmHQ

 

 

 

coHpoonpmHo moopoeoz--.m mqmda:

 

 

 

 

 

 

m
* m .m
* * * H mmmH
* ocmH * * m «H hm:
* * * * * * * m
* comm ccwH * ocmH * * * * H
* * m
* * m .m
* . * * * * H HmmH
* oooH * * * m .mm .ooo
* * * comH * m
oowH ccmH * * * * H
o
* m
* H .m
* * * m mcmH
* * * * * * m «mm thh
* * ocmH * * * comm * * H
* o
* m .m
occH * H HcoH
* * * * m “m .owm
* * * * * m
* ccmH * * * H
H m m m m m m m H H m o m H m H m A.Eov poomcmmu
H+M H-c spoon one oooo
Ampopoe :HV omom m_pmuo3 Eopm mocmpmHm

 

 

 

 

 

AcoSQHpcoovnu.c mHm<B

6O

eupsammon regions. Though most individuals inhabited the
t0p 3 cm. of sand, there was a considerable number of occur-
rences below that depth down to 6 cm.

Seasonal distribution of nematodes followed that of
the testacea with low pOpulationS in the winter and high

in the summer months (Figure 4).

Rotifera Distribution

 

Excepting the c0pepods this is a psammon group which
has received comparatively much attention by past workers,
consequently considerably more is known of Rotifera
psammolittoral ecology than of the other major groups found
in the sand. Wiszniewski (in Neel, 1948) in Poland and
Meyers (1936) and Pennak (1940) in this country have done
extensive studies of the psammon rotifers.

Compared to other investigations of the sand the Mud
Lake psammon contained a rather meager rotifer fauna
(e. g. Meyers (1936) found 145 species in New Jersey and
Wiszniewski (in Pennak, 1940) 105 in Poland). However,
in the preliminary observations of "live" sand rotifers
were among the most abundant animals in the sand; most
likely the treatment for extracting the organisms was too
severe for the majority of this phylum.

General distribution: Due to the few numbers of both
Species and individuals found it was not advantageous to

Separate the rotifers into Wiszniewski's (in Pennak, 1940)

61

 

 

 

 

 

 

 

 

:
oomH * m .m
* * * * m HmmH
* * oomH * H .mm .eoo
m
m
3
m .H
m momH
oooH * H .mm ones
‘4
m .H
m momH
H .H .soe
H
m .H
* m meH
* oooH oooH H .mH .>oz
* * H
comH * * m .H
occH m HcmH
* oooH * oomH. oooH H .mH .poo
H m.m m m.N N m.H H m. m. H m.H N A.Eov vommcmhp
H+c Hip; spoon one memo
Amhopoe :Hv owcm m.moum3 Eonm oocmpmHm
.soHpanepmHo meoHHeom--.m mHmHB

62

 

 

 

 

 

 

H .m
m mmmH
* * m ..H hm:
H
ccmH @
m
* H .H
m meH
* * * m «mm .poc
* * * H
m
m
H .m
ccmH m mmmH
* m «Nm hHSb
* * ccwH * ccmH * H
H .m
m HcmH
* 2 m .m .ooo
* comm * H
m.m m.m m m.H H m. o m. m.H m A.Eov poomcmhp
hHV Auv Samoa ocm sumo
Amhopoa :HV mwom n.90pm3 Song mocmpmHQ

 

 

 

HooHoHocoov--. m mHmHB

63

psammobiotic (rotifers found only in the-sand), psammOphile
(rotifers of the sand which also occur in the vegetation

of the littoral zone), and psammoxene (rotifers character-
istic of the plankton and which are accidental to the sand

and unable to persist there for any length of time) ecological
groups. Horizontally, rotifers of the ploimate group were
found from 2.5 m. landward to 1.5 m. into the water with

the majority occuring in the hygrOpsammon region; vertically
individuals were found to a depth of 4 cm. though most
inhabited the t0p 2 cm. of sand. Psammoxene genera such

as Keratella Sp. and Kellicottia Sp. appeared in one or

 

 

two of the samples.

Seasonally, rotifers were never abundant. Higher
pOpulations were present in the October 18 and July collections
than in any of the other samples. Rotifers were low or
absent from November, April, and May collections. Wiszniewski
(in Pennak, 1940) reported maxima in June and September
and absence of rotifers from November to April in Poland;
Pennak (1940) agrees with this. Not enough counts, however,
were made to determine, in a similar way, the characteristic

seasonal variance of the Mud Lake Rotifera.

Tardigrada Distribution

 

Two Species of Tardigrada inhabited the Mud Lake sand:

Macrobiotus dispar Murray and Hypsibius granulifer (Thulin)

 

Marcus. Tardigrades were found in each of the three transects

64

 

 

 

 

 

 

H .m
m HooH
m .wm .ooo
* * H
H .m
* m HmmH
* * * m «M .omm
* ccHHH * comm H
o
m
H .m
* * m HmmH
* * * m «mm .poc
* * * H
c
m
H .H
m HcoH
* m .mH .>oz
* comm * * H
m.m m m.m m m.H H m. o m. H m.H m A.Eov poomcwhp
A+V HIV Samoa one ome
Ampopoe CHV owom m_mopm3 Eomm mocmpch

 

 

 

.GOHpSDHmpmHU mommecmeun.H:qumHB

65

studied, but their appearance, at least as adults, was
limited to the months of October, November, and December.
If this represents pOpulation maxima, the present findings
differ,somewhat, from the end of May to the end of June
peak that Pennak (1940) found in his sand samples. Pennak
(1940) discussed distribution, general ecology, and seasonal
variation of tardigrades in some detail in his Wisconsin
investigation. His findings with regard to the ecology
of this group in the sand are the most comprehensive thus
far.

Both Neel (1948) and Pennak (1940) found great
instability in the tardigrade population; Pennak (1940)
in fact, states that ". . . populations of Tardigrada on
any beach are almost unpredictable and that they may vary
greatly over a period of time." In the Mud Lake sand
tardigrade occurrence, both horizontal and vertical, was
also sporadic though there was a distinctly greater number
found in the landward portion of the psammon (see Table 10).

Vertically this group was not found below 3 centimeters.

Oligochaeta Distribution

 

Very little is known of the oligochaete fauna of the
sand, either of the kinds which typically inhabit the psammon,
of the seasonal abundance, or of the environmental factors
influencing its distribution as well as the nature of the

distribution along the psammon.

66

 

 

 

 

 

m

oH om m
H .H
oH oH pH oH m mooH
oH mm m .mm page

oH oH mm oH o o oH H

m

0H m
H H .H
mH mH wH m HmmH
oH mm oH m .mH .>oz

o oH Ho mm ooH mm H

mH NH

Hm HH

oH

m

m

S

m

m
oH H HomH
mm oH mm m .mH .eoo

mH Hm mH mH mH m

ow 0H om mH Hm H
m.m m m.m m m.H H m. o m. H m.H H.Eov poomqmmu
H+c H-c spoon one open

 

AmmopoE :HV owom m.poum3 Eopm mommpmHm

 

 

 

.soHospHnenHo oooesoowHHo--.HH mHmHB

67

 

 

 

 

 

 

 

 

o
m
0H oH H .m
mH m momH
mH m .H as:
o o o o o mHH H
oH o
oH oH m .m
mH mm H HomH
oH oH oH mm oH m .mm .Hoo
oH wH mm Hm 0H m
wH mm mm om mH mm H
H .m
m mooH
m .sm sHso
o o o o o o o 0H 0H o H
oH oH oH o
Ho m
oH oH mm H .m
mH oH mH oH m HomH
mm oH oH mm mm m .m .ooo
oH oH om wH H
m
m
5
pH o
oH oH m
oH oH oH mH H .m
oH mm oH mm oH m HomH
mm mH mm mH wH mH m .mm .ooo
mH oH mHH mH ow oH Ho ow H
H m.m m m.m m m.H H m. o m. H m.H m H.26V possess»
spoon one open
H+H H-c
Hmmmpoe :HV owom 9.8.83 5099 005335 1

 

l‘)

Hooschcoov--.HH mHmHB

68

Oligochaetes of four genera were present in the Mud Lake--

sand: Pristina sp., Chaetogaster Sp., Aelosoma Sp., and

 

 

Stylaria sp.; the latter two were found only in the pre-
liminary investigation when "live" sand samples were inSpected.

Of the two genera found in the study, ChaetOgaSter~Sp.-

 

was consistently the more abundant in the sand.

Horizontal distribution: Oligochaetes were dis—

 

tributed in nearly the same numbers lakeward as they were
landward in contrast to the Copepoda and Testacea which

were distinctly more abundant in the beach region as compared
to the shoals. This observation agreed with that of Neel
(1948). Nor did this group show a distinct preference for

a particular portion of the sand in their horizontal
distribution but instead were relatively evenly distributed.
Therefore, in contrast to the c0pepod distribution, which

was characterized by a peak concentration in a particular
portion of the beach, oligochaetes often exibited several
maxima along a transect (Fig. 11). Vertical distribution:
Here again there was a marked difference between the dis-
tribution of oligochaetes and harpacticoid copepods. Whereas
the c0pepods had an Optimal pOpulation at 2 cm. below the
surface, oligochaetes were most abundant in the t0p centimeter
of sand (Fig. 12), rapidly decreasing in numbers in the
deeper layers; the t0p 3 cm. contained the greatest numbers
of oligochaetes. The greatest depth to which oligochaetes

were found was 12 centimeters below the surface.

Figure 12. Horizontal distribution of Oligochaeta in the
t0p five cc. of sand.

7O

 

 

 

 

 

 

i
540 (
510 l ..__. Oct 18, 1961 n
J o-‘--o Nov 12, 1951 T1
I-x-l Jun 25, 1962 T1
480 . o—-—o Oct 22, 1961 '12
‘ hu—c Jul 27, 1962 T2
L‘F-""'a D90 3. 1961 T2
450 , ammo Oct 28, 1961 T3
‘ ‘bX x-o May 1, 1962 T3
420
390 4
J
U l
g 330 4
U)
Q4 4
C>300 1
a .
O
,4 270 .
(D
Q J
9240 J
U)
H 4
8
{30210 .
p
O
%;180 l 2
$4 1 5"
a) _0- O
.0150 / : °.
5 : ‘
Z l ' .
120 :' \ ‘5.
90 . 5. f‘k. °' fl
5 0 3 '7‘
, . ,x‘ .f
60 -. 1’ “\ if ° \
\ . " ‘
i Q!” . “ . I’o/Ko“ ‘ \
3o . A ' )4: v; ‘. , .33
15 ( A<::-ikk. ~+ ‘ #$g’ *" 5
\IF- 4;_. #r— *\Q:——H¢—:--

2.0 2.5 3.0 3.5 4.0
('3’? m)

1.5 1.0 0.5 o 0.5 1.0 1.5
(-) (+)
Distance from water's edge

Figure 13.

71

Vertical distribution of Oligochaeta.

 

 

 

of sand

Number of organisms per cc.

‘ 5.3

72

510 l
480
450

420

it.
390 A

3

C
Li:;54
/.

U
‘o‘
a””.

3 8'
<3 <3
fiHH

2

210

J 5“ \
180 4 | Q .

 

2

60

15

 

 

3—--O
Ir—x-ql
(ya—3
Ab—u-JL
a—---¢1
g...u3

9—AX-G

ertical distance (in cm.)

Oct
Nov

Oct
Jul
Dec
Oct
May

1961
1961
1962
1961
1962
1961
1961
1962

T2

(T2

T2
T3
T3

 

73

Seasonal distribution: In comparison to the Spring and

 

summer collections (April-July) all of the fall and winter
samples (October l8—December 3) contained high—numbers of
oligochaetes; the October 22 collections possessed the

greatest numbers of individuals.

COpepoda Distribution

 

The characteristic c0pepod of the fresh-water beaches,
with one exception belongs to the suborder Harpacticoida,
a group peculiarily adapted for its existence in the sand
intersticies. The three Species found in the Mud Lake

investigation were Elaphoidella bidens coronata (Sars),

 

Pastenocaris brevipes Kessler, and Pastenocaris delamari

 

 

Chappius. Neither Canthocampus Sp.nor Phyllognathus sp.

 

 

the only other genera often found in inland beaches, occurred
in the Mud Lake psammon. According to Yeatman (recent

correSpondance), Pastenocaris starretti Pennak described

 

from a Wisconsin lake by Pennak (1939) is identical with

P. brevipes of EurOpe, and, that which Pennak listed as

 

P. brevipes in the same report is actually P. delameri.

 

 

When these misidentifications were considered, c0pepod fauna
was identical with that Pennak had found in his study

except for the absence of E. b. coronata from Wisconsin and

 

PhyllognathOpuS paludosus Mrazek from Mud Lake.

 

In this study the nauplius larval stage was excluded
from the population estimates, the figures given pertaining

only to the adult individuals.

74

Horizontal distribution: Since it was not possible to

 

break down the distribution of the three species, if indeed
there was a difference in their vertical or horizontal
inhabitation of the beach, the distribution of copepods will
be discussed in terms of the harpacticoid group as a whole.
Harpacticoids occurred from (+) 3.5 m. landward to
(-) l m. lakeward with by far the greater numbers inhabiting
the (—) 5.2 m. region of the beach (see Fig. 13). This
concurs with previous findings of Pennak (1940) and Neel
(1948). Undoubtedly harpacticoids inhabited the sand both
farther landward and lakeward but obviously conditions for
their existence were Optimal from .5—2 m. from the water's
edge where, as mentioned by Pennak (1940), the sand is
neither saturated nor too dry, as well as removed from the
greater portion of wave action. Of the Specimens which

had been identified, E. b. coronata was taken from the O,

 

(+) l, and (+) 1.5 m. stations, P. delamari from (+)

 

1.5-2 m., and P. brevipes from (—) 1.5 to (+) 2 m. Whether

 

these species inhabit Specific portions of the beach is not

known. According to Neel (1948) Pastenocaris sp. in the

 

Douglas Lake psammon, inhabited only the beach portion.
Vertical distribution: Vertically the most striking feature
was that in virtually every transect harpacticoids exibited
a distinct peak two cm. below the surface (Fig. 14).
Apparently the amount of water above the two cm. depth was

not sufficient for Optimal COpepod existence there.

75

 

oH oH oH o
oo oH m
oH mmH mH oH oH oH H .m
oH wH mmH wH oH m HooH
Ho om osH om ow .Ho om m .mm .eoo
mm oH oH mm mm H
o
om m
H .H
m momH
m .mm been
o o o oH oH o H
H .H
wH mm mH m HooH
mm oH mm Hm m .m .>oz
o oH mm oH wH mm H
oH m
H
o
m .H
mmH oH Ho H HooH
oH ooH om mH m .wH .ooo
oH ooH Ho oH mm m
oH oH o H
m.m m m.m m m.H H m. o m. H m.H H soc someones
spoon one some

 

H+c

 

 

 

Hmpopoe :Hv omom n.90um3 Eopm mocmpmHQ

 

 

 

.eoHesoHsonHo ooooooo oHooHeoeonem--.mH mHmHe

76

 

 

 

 

 

 

o
H m
oH oH wH H .m
oH oH mH Ho oH m mmmH
oo. Ho HHH 3 23 a H see
oH om Ho oeH mew oH mom oSH H
mHH w
mm s
oH o
mm m .m
mH oH H HooH
oH wH Ho om mH m .mm .ooo
mm mm om HHH new oH m
o oH Ho mm mm Ho H
H .m
m momH
mm oH m .sm HHso
o oH o o oH oH o o H
mm o
oH oH Ho m
oH oH oH H .m
oH Ho oH mH m HooH
mm Ho mom oH m .m .ooo
oH o mm oH o o H
m.m m m.m m m.H H m. c m. H m.H m H.Eov poomcmnp
H+c H-c noooo one open
AnnouoE :HV owom m.Hopm3 EOHH oocmpmHm

 

 

 

Hooanenoov--HwH mHmHB

ll 1. I‘ll
ll‘I‘lll‘lill‘illl

77

Figure 14. Horizontal distribution of harpacticoid
COpepOds in the tOp five cc of sand.

i__. _ ______ __ 2..— _—___ .— ._—._—_. _...__ ._._——-—-_- — _ _ _ _- fl

 

 

 

1:l~i9g?:2H92J
m1T¢TZTmLmiT.T_ XX‘lH
mmwmwmmw ##\\
0/ OJ 9 OH OJ 04 0H C, \%.$\
111¢1rlqifi41:l ./
’ ' ’ ’ ’ , 9 ’ x
8252m381 an
1:1n69_ 9. /. A
+ov +6 c+ov. s
CHOMWCMuovcno 4\\ \\ x
D ..X . .1 x s
.4—Hd“_ . _||.IXX|I|.I.\- [A ...§
.Xo . o ”45 XX\XX o\ .../.0\\
_ H _ ” ... 1-... an)... .\ \Jr,
. ... x ‘XX‘ ‘7‘.-. o .\ M
o \o
I““‘)- ‘41) k .
.. iii.\||II|I. %/
:nrlc.nllll;nn .Illxx
'0].
all.
5» -H H...
8 XX\ ........
\ o o.
a; -. -.iiux xulillitxx ........ -iiiii.
LAX x .-..iflfi xx 3 n O o 0 O ”\u
xx 4. X X X . . . I all
x Ix x . .. . . . .
Inlllli I: - - ...i I . --x-x
: + L
d— 1 4 4 4 4| 4‘14 ) {1* 4 11 {41 1 J1 lHl 1 J T d 4 4 14 H 1 5 1 J
nu flu nu nv Av AU AU AU nu ad AU
MN m m m m m MW P} 6 _.J O ”I an... 1 Ho ..., r; m
no Cu 5 5 .4 h... 3 H9 7) 7) ._ On 0,. 1 «.1 l

ocom mo .00 Hog mEchmmno mo 909552

}m

 

410

‘T

 

 

0.5 1.0 1.5 2.0 2.5 3.0 3.5

(+)

13'! :annn f‘vanm mptnvflq 95153:.

  

(in m)

Figure 15.

79

Vertical distribution of harpacticoid COpepOdS.

_~__.__*———4

 

Iliuu'otcnwsmhmu/cuzOrland

390
360
330
300
270
240
210
180
150

120

 

 

 

1961
1961
1962
1961

.1962

1961
1961
1962

 

 

 

Vertical distance (in cm.)

10

11

12

13

81

Harpacticoids were found to a depth of eight cm.
below the surface; they have been known to occur as deep
as 11 cm. (Pennak, 1940). Whether there was-a preferential-
vertical distribution among the three Species of harpacticoids
as was found in the studies of COpepOdS-inhabiting marine
beaches (Nicholls, 1935) was not determined. Seasonal
distribution: As with the distribution of oligochaetes
along the beach, there seemed to be an indication in the
data that during warmer periods harpacticoids move towards
the hygro--and hydrOpsammon portions of the beach (Fig. 13)
as well as.into the vertically deeper portions of the beach
(Fig. 14). COpepods were collected from every transect and
at all times of the year except in the April collection.
Highest pOpulations were found in the May collection when,
paradoxically, numbers of other psammon organisms were
lowest (Fig. 3).

High pOpulations were also found in October (T2, T3).
lower ones in November and December, and the lowest pOpula-
tions occurred in the June and July collections. NO COpepOdS

were found in the April collection.

Cladocera and Malacostraca Distribution

 

In every instance cladocerans were collected from the
Shoal region of the psammon, and, in nearly every instance
from the tOp(cm. Table 6). This implies that this group was
most likely an accidental visitor to the psammon rather than

part of the psammolittoral fauna. In addition cladocerans,

82

unlike the COpepOdS, possessed no particular morphological
adaptations for life in the sand interstecies.

In two instances Single individuals of Hyalella
azteka (Saussure) were found. These, like the cladocerans,

represented incidental elements to the psammon.

LarVal Insect MalaOOStraca DiStribution

 

Larval dipterans occurred in a few samples but never
in great numbers. Larvae of the families Tentapedidae,
Delicapodidae, and Chironomidae were found but not in
sufficient numbers to discern distributional patterns.

An occasional Podura aquatica L.appeared in some samples

 

as well but these were incidental to the psammon. Neel
(1948) found larvae of two Diptera families: chironomids,
which were infrequent, and ceratOpogonids of which eggs and
larvae were common, in the Douglas Lake sand. He also

found larval homophrinids (Coleoptera). Pennak (1940)

found the distribution of Diptera larvae to exibit no maxima
or minima along any portions of the psammon although his
data, as in this study, was somewhat insufficient to make
definitive evaluations.

If one were to total (from Table 13) the number Of
larvae found in the shoal region (+) against the number
found in the beach portion (-) of the psammon, these numbers
would be approximately equal indicating an even distribution
throughout the sand. However, also apparent from table 13
is the fact that most of the larvae occurred in the hydro--

and hygropsammon regions; very few were found in the eupsammon.

83

 

 

 

 

 

 

 

 

H .m
oH m HomH
m .m .ooo
o o o o o o c o H
m
wH H .m
m HmmH
m nmm .uoo
o o o o o o cH cH H
H .H
m mmmH
oH m .mm onso
o o o o 0 0H H
H .H
o o o cH m HcmH
o o o m .mH .>62
0 o o c o cH o o H
o o o H .H
o o o o m HcmH
o o o o oH m .wH .noo
o o o o c o o H
m.m m m. m.H H m. o m. H m.H H.EOV Hoomcmhp
m m nonoo one some
E E
Ammouoe :Hv owom n.20pm3 Soon oodmumHm
.COHuanHumHo poomcH omsmeEHnu.mH mHmHE

84

 

 

 

 

 

m

oH s

o

m
H .m
m HooH
m .mm .eoo

o o o o mm oH o H
H .m
m mooH
m .sm HHso

o o oH o o o o o o H
H m.m m m.m m m.H H m. o m. m.H m H.26v sameness
H+c H-c noose one open

 

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85

Seasonally, because of the lack of data, one can make --
only a cursory statement regarding variations: Insect
larvae in the Mud Lake psammon were most abundant in the
October (T2, 3) collections and least abundant-in the

December, April, May, and July collections (Fig. 3).

Acari Malacostrace Distribution

 

An arthrOpod group not previously reported from the
psammon, but one which would be expected to occur there,
was the Acari. Mites were found in every collection but
two and in every transect. Though most mites were generally
found in the tOp two cm. the distribution of these animals
was Sporadic, there being neither a consistent horizontal
(Fig. 15) nor vertical (Fig. 16) preference for a particular
region of the psammolittoral zone. Vertically, individuals
were not found below four cm. Landward, mites inhabited
the psammon to (+) 4 m., which was the limit of landward
collection. One would anticipate mites to inhabit all portions
of the psammon above the water-line, however, a considerable
number occurred in the Shoal region. AS far as could be
determined all the individuals collected belonged to the
Oribatei and not to the Hydracarina (water mites). A great
number of mites were collected in the psammon below the
water line.

The greatest numbers of mites were found in December
collections (Fig. 3) when one could expect the lowest popula-
tions. No mites were found in the April and June collections

and low numbers appeared in the October 18 and May samples.

86

 

 

 

 

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87

 

 

 

 

 

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88

Figure 16. Horizontal distribution of mites in the
tOp five cc of sand.

Number of organisms/"cc. or sand

510

480

450

420

390

360

330

300

270

240

210

180

150

120

90

60

30
15

 

89

D-m—Cl Oct 22,
chum-aiJul 27,
L‘s—'I—A D90 3'
inn-0"} 001'; 18,
0—0 Nov 12,
(D—XX-c May 1,

  
 

 

1961
1962
1961
1961
1961
1962

.0 ‘ '0‘ ’1‘
S "\‘ ~\~'—(‘.+

 

 

(+)

Distance from water's edge (in M)

0.5 1.0 1.5 2.0 235 315 315 4:0

Figure 17.

90

Vertical distribution of mites.

 

 

Number of organim/ cc. of sand

. 91

510‘

480‘ D—--D Oct 22, 1961 T2
‘ ...... Jul 27, 1962 T2
< A—--A Dec 3, 1961 T2

450 e ..... e Oct 28, 1961 T1
‘ (L --0 Nov 12. 1961 '1‘].

4201

390w

360a

330-

270~

240‘

 

 

 

 

1 3 1:6 78910

Vertical distance (in cm.)

92

Other'MetaZOa

 

Both gastrotrichs and turbellarians-have been found
in previous psammon studies Pennak (1940) and Neel (1948).
Representatives of both phyla were found in considerable
numbers in the preliminary investigations of unpreserved
sand samples. However, as in the case of the non—testaceous
protozoans, the means of extracting and preserving psammon
organisms destroyed the identity of these soft-bodied
specimens with the result that they could not be included
in the study.

VI. SUMMARY

An ecological survey study was undertaken in 1961-
1962 on the psammolittoral zone of Mud Lake (T.2 N., R.9 W.,
3.8, Barry 00., Michigan) investigating the seasonal dis-
tribution, Spatial distribution, and some of the environ-
mental factors influencing the organisms inhabiting
capillary interstecies of the sandy zone.

Though, admittedly, there are many non—biological
variables Operating to restrict the vertical distribution
of psammo—microorganisms, a major non—biological factor
whenever it was present appeared to be the black sulfide
layer. The exact importance of this stratum in restricting
the vertical occurrence of organisms was not know. Other
environmental factors and their variance were discussed but
no correlations with population characteristics were drawn.

Biologically the following statements can be made
about the Mud Lake Psammon:

l. The psammo-organisms in approximate order of

decreasing abundance were:

Algae; diatoms, blue-green, green, Euglenophyta.
Animals; testaceous protozoa, Nematoda, rotifers,
c0pepods, oligochaetes, mites, insects, and
cladocerans.

2. Horizontal, vertical, and seasonal distribution

of the major taxons occurring in the sand were

discussed:

93

94

a. The population maximum for the vast majority
of psammo-organisms insofar as their
horizontal distribution was concerned,
occurred in the middle portions of the beach
(i.e. the hygro- and eupsammon).

b. Vertically, most of the organisms inhabited
the tOp three cm. of’sand.

Seasonal patterns in distribution were not, in
most instances, distinct, though a few groups did
exhibit distinct pOpulation maxima and minima at

certain times of the year.

SELECTED REFERENCES

Anderson, R. O. 1959. A modified flotation technique for

iorting bottom fauna samples. Limnology and Oceanography.
:2. Si

Fisher, R. A., Corbet, A. S., and Williams, C. B. 1943.
The relation between the number of species and the
number of individuals in a random sam 1e of an animal
population. Jour. Anim. Ecol. 12(1): 2—58.

 

Meyers, F. J. 1936. Psammolittoral rotifers of Lenape
and Union Lake, New Jersey. Am. Mus. Novitates. 830:
1—22.

 

Moffett, J. F. 1943. A limnological investigation of the
dynamics of a sandy wave-swept shoal in Douglas Lake,
Michigan. Trans. Am. Micro. Soc. 62(1):1-23.

 

Moore, G. M. 1939. A limnological investigation of the
microscopic benthic funa of Douglas Lake, Michigan.
Ecol. Monog. 9:537—582.

 

Neel, J. K. 1948. A limnological investigation of the
psammon in Douglas Lake, Michigan, with especial
reference to shoal and shore-line dynamics. Trans.
Am. Micro. Soc. 67(1):1-50.

 

Nicholls, A. G.‘ 1935. COpepods from the interstitial fauna
of a sandy beach. Jour. Marine Biol. Assn. 20:379—405.

 

Pennak, R. W. 1939. A new COpepod from the sandy beaches
of a Wisconsin lake. Trans. Am. Micro. Soc. 58:224-
227.

 

Pennak, R.W. 1940. Ecology of the microscopic metazoa
inhabiting the sandy beaches of some Wisconsin lakes.
Ecol. Monographs. 10:537-615.

 

Pirrie, N. E., Bruce, J. R., and Moore, H. B. 1932. A
quantitative study of the fauna of the sandy beach at
Port Erin. Jour. Mar. Biol. Assn. 18:279-296.

 

95

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