MAJOR ELEMENT AND NUTRIENT CHEMISTRY OF GREEN AND ROUND LAKES, NY

Green and Round lakes are adjacent meromictic lakes near Fayetteville, NY. Profiles of Green Lake were completed at a 1 m interval to a depth of 30 m for temperature(T), specific conductance (SpC), dissolved oxygen (DO) and pH. Water samples were collected at seven depths from the surface to 23 m. This allowed access to the upper level of the monimolimnion. Only surface water samples were collected on Round Lake as access to the lake is prohibited. A chemocline was found to be persistent between 17 and 20 m depth, based on SpC. Additionally, an increase in SpC is seen from the surface to approximately 4 m depth, with relatively constant values between 4 m and the start of the chemocline. Temperature profiles show a shallow epilimnion and a relatively thick metalimnion. Temperature increases at the base of the hypolimnion, then rapidly decreases in the chemocline. Values of pH range from 6.1 to 7.3 within the mixolimnion, but rapidly increase to near 8 below the chemocline. Dissolved oxygen concentrations typically range from 6.7 to 9.5 mg/L in the mixolimnion, but drop to concentrations below 0.6 mg/L below the chemocline. Major cations and anions are dominated by Mg and K, and SO₄ an Cl, respectively. Concentrations of Mg were found to range from 285 to 466 mg/L, and show an increasing trend with depth. Sulfate concentrations range from 234 to 678 mg/L, and show a similar increasing trend. Nitrate concentrations vary from 1.8 to 4.1 mg/L with the lowest values below the chemocline. Comparing surface samples from Green and Round Lakes found slightly lower concentrations of all solutes in Round Lake.