Seasonality is a major factor influencing freshwater ecosystem dynamics in temperate regions. Diatom taxa attain peak abundances under different seasonal environmental conditions. This study aimed to track seasonal and environmental changes in diatom abundance and water quality parameters over the course of a year (June 2015 – December 2017). Three research questions were investigated: (1) What are the water conditions associated with the most abundant diatoms? (2) In what season are diatoms most abundant? (3) Do diatoms change with seasonal water changes? Results are reported for vertical tow, van Dorn samples and suspended glass slides that were collected each month. Chlorophyll and biomass measurements were conducted in the lab for diatom productivity. Correspondence of water quality parameters to relative abundance of diatom tax was assessed.
Results/Conclusions
This study tracked seasonal and environmental changes in diatom abundance and water quality parameters over the course of three years. A noticeable shift in relative abundance of diatom taxa occurred in the reservoir (Fragilaria-Asterionella-Aulacoseria). Both positive and negative correlations were found between water quality parameters and relative abundance of diatom taxa. Correlations were found between temperature and Cyclotella ocellata and Aulacoseria granulata. In the spring Asterionella formosa, Cyclotella ocellata and Fragilaria crotonensis reach maximum abundance. In the summer Aulacoseria granulata reached maximum abundance. In the fall none of the diatoms studied were found to reach maximum abundance. The most dominate diatoms found in the spring were F. crotonensis and A. formosa. The most dominate diatoms found in the summer were A. Formosa, F. crotonensis and A. granulata. A longer term data set generated by additional research will be useful for more robust statistical analysis. Diatoms are important proxies for paleolimnological studies, and the results from this study can be used to better calibrate diatom inferences in future studies, particularly those conducted in reservoirs.