Date of Award

Spring 2021

Document Type

Open Access Thesis

Department

Marine Science

First Advisor

Jay Pinkney

Abstract

Stormwater detention ponds (SDPs) on the coast of South Carolina have become increasingly prevalent as the area experiences rapid urbanization. SDPs are man-made reservoirs implemented to minimize pollution inputs into receiving waters and are home to diverse biota, including zooplankton. Zooplankton are a good water quality indicator due to their quick response times and trophic regulators of phytoplankton through grazing. Zooplankton and phytoplankton interactions in stormwater detention ponds are an essential component for understanding plankton community dynamics in SDPs. This purpose of this study was to determine the seasonal variability in zooplankton community composition and grazing rates at 14-day intervals in one SDP located in Murrells Inlet, SC. Zooplankton samples were collected using a diaphragm pump as well as a 150μm net. Grazing experiments were conducted via 12-hour incubations in the dark. Copepods and cladocerans were the most abundant mesozooplankton groups throughout the sampling period, although nauplii had a large increase in the October months. Temperature and chl a were correlated with zooplankton abundance (p<0.05), while zooplankton were relatively tolerant to low DO concentrations. Microzooplankton community structure also shifted along with temperature change. Netzelia was the most abundant genus followed by Paramecium until August 20th. After this date, Paramecium was dominant and Netzelia was a minor part of the community. Cyanobacteria abundance (based on zeaxanthin concentrations) had no effect on zooplankton abundance, possibly due to low cyanobacteria concentrations. The average amount of phytoplankton grazed per day for the microzooplankton only treatment was 0.66 (± 0.30) μg chl-a L-1 d-1 and 1.00 (± 1.22) μg chl-a L-1 d-1 for the combined micro and meso treatment. Mesozooplankton contributed to phytoplankton grazing as much as microzooplankton and both groups had low to non-existent grazing on cyanobacteria. Cyanobacteria could be a nuisance to the SDP if they bloom and other management strategies, outside of zooplankton grazing, should be explored to prevent possible cyanobacterial blooms in the future. This is the first detailed study of zooplankton community structure and grazing in an SDP in coastal South Carolina and highlights the need for additional research in this area.

Rights

© 2021, Kristen Laccetti

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