LE3 .A278 2011

2011

Spooner, Ian

Acadia University

Bachelor of Science

Honours

Environmental Science

Earth & Environmental Sciences

It is necessary to understand contemporary and historical processes operating in lakes and catchments in order to develop effective lake management strategies and assess risk associated with development or changing climate. This study focuses on assessing the vulnerability of a shallow lake to small variations in water depth. The lake has recently been subject to controversial short-term water level changes that have been a consequence of development pressure at the lake. Historical data indicates that dam construction in 1920 resulted in water level change. Lake survey data indicates that strong storms have the potential to create sufficient bottom shear to re-suspend lake bottom sediment. A 200 year-long lake sediment record indicates a change from dominantly siliceous autochthonous diatom-rich sediment to allochthonous organic-rich sediment in 1920. Chemical data from the lake sediment indicates consistent nutrient concentrations but increases in metal concentration (Pb, Ni, Cu, As) associated and coincident with an increase in lake sediment organic content. Higher lake levels were likely caused by hydroelectric dam construction. An increase in organic input from a sawmill likely led to available metals being complexed with organic matter. The data indicate that Tupper Lake is susceptible to episodic sediment resuspension related to storms and lower lake levels. Higher water levels may result in an increase in organic influx into the lake and associated water quality degradation. It is likely that many other lakes in Atlantic Canada experience substantial water quality change in response to similar processes. Lake management strategies are required to address the risk associated with drawdown.

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https://scholar.acadiau.ca/islandora/object/theses:763