Cyanobacterial Contribution to Annual Cycles of Phytoplankton in Lake Murray, SC

Haley Durbin, University of South Carolina
Mikayla Radek, University of South Carolina
Catherine Schlenker, University of South Carolina
Sarah Bauman, University of South Carolina
James L. Pinckney, University of South Carolina

Article Type

Full Research Article – Special Issue

Volume

Issue

Abstract

Freshwater lakes provide valuable recreational and tourism resources and are a major source of municipal drinking water for local communities. A primary management goal for lake systems is the maintenance of good water quality and a healthy aquatic ecosystem. Blooms of harmful or noxious species of cyanobacteria can result in severe water quality degradation. The purpose of this project was to provide baseline data on phytoplankton community composition, with special emphasis on cyanobacteria, and water quality parameters for Lake Murray, SC. The objective of this study was to determine the annual cyanobacterial contribution to total phytoplankton biomass in the lower reaches of Lake Murray. Measurements for this study were obtained at weekly to biweekly intervals from May 2021 to August 2022 on the northeast side of Lake Murray Dam, SC. Phytoplankton community composition was determined using a combination of high-performance liquid chromatography (HPLC) and ChemTax methods to measure the relative abundances of different algal groups. The phytoplankton community in Lake Murray is composed of a diverse assemblage of primarily green algae, diatoms, cyanobacteria, cryptophytes, and dinoflagellates. Community structure varied seasonally and annually. Total phytoplankton biomass remained below 7 μg of chl a l-1 and never reached “bloom” proportions (e.g., > 40 μg of chl a l-1). Planktonic cyanobacteria were present year-round in the lower reaches of Lake Murray and comprised 5–40% of the total phytoplankton biomass. Peaks in cyanobacteria abundance occurred during the late summer months. Even at the peak in August 2021, concentrations of cyanobacteria were low (1.79 μg chl a l-1). Over annual cycles, cyanobacteria had a median chl a concentration of 0.63 μg l-1 and a median contribution of 14.9%. Although we were unable to identify any specific causal mechanisms for the fluctuations in cyanobacterial biomass, we demonstrated that cyanobacteria are a consistent component of the phytoplankton community in lower Lake Murray. Baseline measures of phytoplankton during “good” water quality conditions provide invaluable data essential for managers to establish criteria for early prediction of bloom events and evaluate the effectiveness of mitigation strategies. Departures from the norm, especially during the summer and early fall, may signal the beginning of a cyanobacterial (or other algal group) bloom and provide an early warning for recreational users and municipal water intakes.

Takeaway(s)

none

Recommended Citation

Durbin, Haley; Radek, Mikayla; Schlenker, Catherine; Bauman, Sarah; and Pinckney, James L. (2024) "Cyanobacterial Contribution to Annual Cycles of Phytoplankton in Lake Murray, SC," Journal of South Carolina Water Resources: Vol. 9 : Iss. 2 , Article 13.
Available at: https://tigerprints.clemson.edu/jscwr/vol9/iss2/13

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