GEOCHEMICAL MODELING OF MEROMICTIC GREEN LAKE, FAYETTEVILLE, NY

Green Lake a meromictic lake in Fayetteville, New York has been extensively studied. Meromictic lakes have no seasonal mixing of their waters, resulting in permanent stratification of their layers into mixolimnion (top layer), chemocline (middle layer), and monimolimnion (bottom layer). Supersaturation of calcium ions and seasonal blooms of Synechococcus bacteria result in biomineralization of calcium carbonate called “whiting events”. The recognition of these biogeochemical process led to several studies of water chemistry in the 1960s, but work over the last 50 years has focused on microbial communities and lake sediments with almost no updated publications on water chemistry. Questions about seasonality and chemical variations within individual whiting events still have not been addressed. In this study, an aqueous geochemical database was created for the purpose of better understanding biogeochemical cycling in Green Lake and modeling temporal changes in water chemistry. Conductivity, pH, alkalinity, cation, and anion concentrations were measured 4 times during one season’s whiting event. We concluded that pH, conductivity, and major ion trends were similar to prior data, however the values were consistently lower than previously recorded. Compiling this data allowed us to use an Equivalence Evaporation (EQL-EVP) model to explore potential effects of seasonality and climate change on the biogeochemical cycling in this unique environment.