OCGC Seminar - Scott Lamoureux and Melissa Lafrenière

   

The impact and recovery of Arctic rivers to permafrost perturbation and disturbance

Professors Scott F. Lamoureux and Melissa J. Lafrenière
Department of Geography, Queen's University 

 

Arctic river

Monday, December 8th, 2014
11:30 a.m.  

Gamble Hall
Geological Survey of Canada

615 Booth Street

 

Abstract

Physical landscape perturbation and disturbance due to permafrost change has been widely documented across the Arctic, and can play an important role in altering the fluxes from slopes to channels and downstream aquatic ecosystems. We have investigated the downstream impacts from an episode of unusually warm summer climate and related permafrost degradation at the Cape Bounty Arctic Watershed Observatory (CBAWO), a long term watershed research program focused on determining the links between climate, water and landscape on Melville Island in the Canadian High Arctic. Research at CBAWO began in 2003 and compiled baseline data prior to the 2007 season, when record summer melt and heavy rainfall resulted in widespread slope disturbances and active layer thaw reached at least 1 m depth. The impact and recovery of the land and surface waters from disturbance and perturbation is poorly understood and motivated us to undertake systematic investigation of the post-2007 catchment response. We have carried out these investigations at multiple spatial scales and focused on hydrological fluxes of sediment, solutes, nutrients and related geomorphic controls. We particularly focused on similar small catchments that represent different disturbance size and morphology, slope position and hydrological connectivity including an undisturbed control catchment. We collected seasonal discharge, suspended sediment and water quality data from the catchments from 2007-14. Results of this long term investigation will be presented and point to the major divergence in response between thermal (thaw related) and physical (disturbance) perturbation of the watershed and provide insights into the timescales for recovery. These results will contribute to our modelling efforts of the impact of climate and permafrost change on surface water quality and land stability, and will also aid in investigating biogeochemical changes in these and similar river settings in the region.