INVESTIGATION OF PROPOSED WATER QUALITY INDICATOR ORGANISMS FOR MARINE MAMMAL ENCLOSURESByChristopher OwenA USDA APHIS proposal would require institutions housing marine mammals to limit concentrations of total coliforms to 500 CFU/100 mL and enterococci, staphylococci, and/or pseudomonads to 35, 10, and/or 10 CFU/100 mL, respectively. Little is known about the amount of water treatment necessary to meet these levels, or significance of said levels, if any, in relation to the total microbial community of marine mammal housing systems and the health of the mammals housed. Using membrane filtration and growth on selective media, concentrations of these indicators were monitored in a system housing Pacific white-sided dolphins over a period of 5 days and compared between exhibit water and water from exhibit plumbing after sand filtration but before ozone treatment. Concentrations were also examined after ozone treatment. Isolates from each media were taxonomically identified using 16S rRNA gene sequencing, and colony counts were analyzed as predictors of 16S rRNA gene community data.All indicator counts were significantly reduced either after sand filtration or after ozone treatment, but none were significantly reduced at both points. Genetic sequencing of isolates from selective and differential media revealed that 10% of presumptive pseudomonads, 19% of presumptive staphylococci, 100% of presumptive enterococci, and 91% of lactose-fermenting total coliforms were members of the expected taxa. Several correlations between indicator counts and individual OTUs from the community as well as overall dissimilarity between community samples were detected.
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