SS3.01 Landscape Control of High Latitude Lake and River Ecosystems
Date: Thursday, June 13, 2002
Time: 11:00:00 AM
Location: Carson A
 
McGowanS, University of Regina, Regina, Canada, suzanne.mcgowan@uregina.ca
Leavitt, P, R, University of Regina, Regina, Canada, leavitt@uregina.ca
Hall, R, I, University of Waterloo, Waterloo, Canada, rihall@sciborg.uwaterloo.ca
Wolfe, B, B, University of Waterloo, Waterloo, Canada, bwolfe@sciborg.uwaterloo.ca
Edwards, T, W, University of Waterloo, Waterloo, Canada, twdedwar@sciborg.uwaterloo.ca
Karst, T, , University of Waterloo, Waterloo, Canada, tkarst@sciborg.uwaterloo.ca
Paterson, A, , University of Waterloo, Waterloo, Canada, a2paters@sciborg.uwaterloo.ca
Vardy, S, R, University of Waterloo, Waterloo, Canada, srvardy@fes.uwaterloo.ca
English, M, C, Wilfrid Laurier University, Waterloo, Canada, menglish@wlu.ca
Boots, B, , Wilfrid Laurier University, Waterloo, Canada, bboots@wlu.ca
 
TEMPORAL AND SPATIAL ASSESSMENT OF THE ALTERNATIVE STABLE STATES HYPOTHESIS IN SUB-ARCTIC DELTA LAKE SYSTEMS (PEACE-ATHABASCA DELTA, NORTHERN ALBERTA)
image
The Peace-Athabasca Delta (PAD) comprises hundreds of lakes, which are replenished by periodic ice-jam flooding of the Peace and Athabasca rivers. PAD lakes may have closed, restricted or open hydrology, dependent on their susceptibility to flooding. Ordination of a sample set of 61 PAD lakes suggested that lakes consisted of two types; those with more closed hydrology, abundant aquatic plants, dominance of benthic diatoms and high total algal production (sedimentary pigments); and those with more open hydrology, sparse aquatic plant growth, dominance of planktonic or epipsammic diatoms and low total algal production. We tested the hypothesis that the delta lakes exist in two alternative stable states and that climatic variability (flooding) likely acts as a “switch” between each state. The hypothesis was tested both spatially by multi-proxy analysis of lake surface sediments, and temporally by analysis of sediment cores. Preliminary analyses suggest that lake types exist along a continuum, rather than existing as separate states.