SS3.01 Landscape Control of High Latitude Lake and River Ecosystems
Date: Thursday, June 13, 2002
Time: 11:15:00 AM
Location: Carson A
 
LesackL, Simon Fraser University, Burnaby, BC, Canada, Lance_Lesack@sfu.ca
Squires, M, , Simon Fraser University, Burnaby, BC, Canada, msquires@sfu.ca
Teichreb, C, , Simon Fraser University, Burnaby, BC, Canada, cjteichr@sfu.ca
Riedel, A, , Simon Fraser University, Burnaby, BC, Canada, ajriedel@sfu.ca
Spears, B, , Simon Fraser University, Burnaby, BC, Canada, bspearsa@sfu.ca
Marsh, P, , National Water Research Institute, Saskatoon, SK, Canada, philip.marsh@ec.gc.ca
 
LAKES OF THE MACKENZIE DELTA: A SYSTEM OF GRADIENTS DRIVEN BY LANDSCAPE EFFECTS ?
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The arctic circumpolar region contains numerous lake-rich river deltas (thermokarst effects) and the Mackenzie delta is an important representative (25,000 lakes). Past and on-going investigations have established that lakes in this delta collectively represent gradients from turbid waters to transparent, unstable transparency to high stability, high dissolved-nutrients to low, low total-DOC to high, high colored-DOC to low, continuous river-connection to long disconnection periods, high inorganic sediment content to high organic sediment, and low under-water UV-irradiance to higher irradiances. Super imposed on these are biotic community gradients ranging from low bacteria to high, low macrophytes to high, high phytoplankton to low, low epiphyton to high, high epipelon at intermediate flooding-frequencies, high small-bodied zooplankton (intermediate flood-frequency) to low large-bodied, high fish to no fish, and low aquatic birds to high. All the above are directly or indirectly linked to lake flooding (river-water) ranging respectively from frequent (long durations) to infrequent (short durations). Links among these gradients will be overviewed to elucidate direct and indirect landscape effects, and implications of recent advances in our understanding of the Mackenzie River flow regime.