Assessing the Impacts of Recent, Intense Permafrost Thaw Slumping on Lakes in the Mackenzie Delta Uplands, Northwest Territories, Canada

Abstract

The Western Canadian Arctic is warming at a rate much more rapid than the rest of the globe. As a result of the increasing temperatures, this is influencing the rate of permafrost thaw throughout the Arctic. One of the most dramatic features that develop from permafrost thaw are retrogressive thaw slump, which are rotational landslide features that develop along the shore of impacted lakes. The terrestrial material from the slump is transported to the adjacent lake, impacting the water quality and health of the lake. In the Mackenzie Delta, due to rapid increases in temperatures, the rate of slump growth as well as the size of slumps are increasing. Due to this increase in slump activity in the area, this research focuses on the impacts of intense retrogressive thaw slump activity in the Mackenzie Delta region. Using a paleolimnological and remote- sensing approach, this research aims to assess the impact that large, highly active slump activity has on the ecosystem of adjacent lakes. Sediment core data taken from highly active slumps in the area allow us to examine the impacts that the slump have on the aquatic environment by looking at the effects on carbon and mercury dynamics within the system. Remote sensing analysis of the slump affected lakes allow us to assess the trends in turbidity in both slump and non slump impacted lakes, to assess differences in the patterns. This research is important as temperatures are expected to continue to increase in the western Canadian Arctic, and as such understanding the effects continued warming is having on slump development and slump impacted lakes is critical for assessing the health of the lakes throughout the region.