Ion Mass Budgets for Lakes in the Turkey Lakes Watershed, June 1981 – May 1983

Ion mass budgets were determined for two water years (June – May 1981–83) for Batchawana L. South, Wishart L., Little Turkey L., and Turkey L. Water budgets balance within measurement error except for Little Turkey L. (output surplus for both water years) and Batchawana L. South (output surplus for 1982–83). Groundwater seepage is hypothesized to explain these water budget imbalances. The chemical budgets show that H + , NH 4 + , and NO 3 − are retained by the lakes to varying degrees. The major input pathway for H + and NH 4 + is via direct atmospheric deposition, while relatively weaker terrestrial retention of NO 3 − causes basin runoff to be the major input pathway for this parameter. All three species are playing an acidifying role on the Turkey Lakes Watershed. Chemical budgets for Mg 2+ , Na + , K + , SO 4 2− , and Cl − are generally balanced for all lakes relative to the water budgets. In contrast, Ca 2+ and acid-neutralizing capacity (ANC) exhibit excess output over measured plus estimated inputs. Probable unmeasured inputs of these two parameters include groundwater seepage and Ca 2+ exchange with the sediments. In-lake generation of ANC by SO 4 2− reduction is of minor importance.