Calcium carbonate deposition in Ca2+ polluted Onondaga Lake, New York, U.S.A.

Seasonal and long-term trends in the rate of calcium carbonate (CaCO3) deposition are documented for Ca2+ polluted Onondaga Lake, New York. These observations are based on particulate inorganic carbon and particulate calcium analyses of sediment trap collections, made weekly over the May-September interval for 10 years. Continuous deposition of CaCO3 was evident for the monitoring period of all 10 years. The average rate of CaCO3 deposition for the deployment interval decreased from about 0.196 to 0.082 mol•m−2•d−1 following the closure of the industrial source of Ca2+ pollution. This decline was generally consistent with the reductions in Ca2+ loading and lake Ca2+ concentrations over the same period. The prevailing rate of CaCO3 deposition in Onondaga Lake remains substantially higher than the rates documented for three other hardwater lakes in the literature. Calcium carbonate is the primary component and principal regulator of the dynamics of total solids deposition in the lake.