AQUEOUS GEOCHEMISTRY OF WESTERN NEW YORK’S MEROMICTIC LAKES DURING SUMMER THERMAL STRATIFICATION

Western New York is home to several permanently stratified meromictic lakes. These lakes, created as a result of retreating ice sheets are significantly different than other lakes of the region. Meromictic lakes are permanently stratified below the chemocline, while the rest of the water column seasonally mixes. Furthermore, meromictic lakes are often characterized by being relatively deep as compared to their surface area. The three lakes included in this study are Green Lake and Glacier Lake, both near Syracuse, NY, and Devil’s Bathtub, located near Rochester, NY. Green and Glacier Lakes are plunge pools, with Green Lake being the deepest at approximately 59 m, while Glacier Lake has a maximum depth of 19 m. Devil’s Bathtub is a kettle lake, surrounded by kame and esker ridges, with a maximum depth of 15 m. Each lake has a stable mixolimnion, but this layer is relatively thin in Glacier Lake and Devil’s Bathtub.

In this study, the water column was investigated during the height of summer thermal stratification. This separates the water column into an epilimnion, metalimnion, hypolimnion and mixolimnion. Field parameters were determined at 1 m intervals, and samples were collected from each layer for laboratory analyses. For all of the lakes, pH is near neutral due to the abundance of carbonate bedrock regionally. Dissolved oxygen drops with depth, approaching anoxic conditions below the chemocline. Results show that the shallower lakes are Na-Cl dominate above the chemocline, but have elevated concentrations of Ca-SO₄ below the chemocline. Total conductivity ranges from 0.5 to 1.5 mS in these lakes. Green lake, however, is Ca-SO₄ dominate throughout the water column, and has significantly higher total conductivity, ranging from 1.8 to 2.6 mS. Analysis of trace elements and H, O and S stable isotopes is being completed to help elucidate sources of water and possible mixing within these lakes.