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

Abstract

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+, NH4+, and NO3− are retained by the lakes to varying degrees. The major input pathway for H+ and NH4+ is via direct atmospheric deposition, while relatively weaker terrestrial retention of NO3− 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 Mg2+, Na+, K+, SO42−, and Cl− are generally balanced for all lakes relative to the water budgets. In contrast, Ca2+ and acid-neutralizing capacity (ANC) exhibit excess output over measured plus estimated inputs. Probable unmeasured inputs of these two parameters include groundwater seepage and Ca2+ exchange with the sediments. In-lake generation of ANC by SO42− reduction is of minor importance.