Evaluating bio indicator response to recovery from anthropogenic acid deposition in a drinking water source in Halifax, Nova Scotia

Abstract

Little is known about the biological response to anthropogenic acidification in Atlantic Canada. A multi-proxy paleolimnological investigation of Pockwock Lake, the main drinking water supply for the City of Halifax, was conducted to assess biological response to chemical water quality change and recovery trends. This thesis provides information on Cladocera and diatoms assemblages, and inferred chlorophyl a and TOC. It appears that Cladocera have not responded to increases in lakewater pH, ANC and alkalinity in Pockwock lake. This lack of response is most likely due to regional Ca concentration decline. Diatoms do show a response and return of two major species dominating the assemblage with low pH and high DOC optima. VNIRS-inferred chlorophyl a and TOC results show a chemical and biological return to pre-impact conditions and suggest unprecedented water quality trends have begun to occur.