Comparison of the Characteristics of an Acidic Eutrophic, and an Acidic Oligotrophic Lake Near Halifax, Nova Scotia

Abstract

The chemical and biological characteristics of two lakes near Halifax, N.S., are reported. Both lakes have been acidified as a result of the oxidation of exposed sulfide minerals in their drainage basins. Little Springfield Lake (mean pH = 3.6) is oligotrophic, with low concentrations of dissolved nutrients, high concentrations of metals, clear water, and relatively depauperate plant and animal communities. In contrast, Drain Lake (mean pH = 4.0) receives domestic sewage and is eutrophic, with high concentrations of phosphorus, low transparency, and relatively rich and productive plant and animal communities, including the anomalous occurrences of many taxa that are usually restricted to higher-pH waters. An important implication of this study is that fertilization may be a useful management technique to reverse the oligotrophication that generally occurs in acidified waters.