Leavitt, P. R.. University of Regina, peter.leavitt@uregina.ca
Graham, M. R.. University of Regina, grahamma@meena.cc.uregina.ca
Cumming, B. F.. Queen's University, cummingb@biology.queensu.ca
Smol, J. P.. Queen's University, smolj@biology.queensu.ca
Reasoner, M. University of Colorado, reasoner@spot.colorado.edu
Hodgson, D. British Antarctic Survey, daho@pcmail.nerc-bas.ac.uk

 
THE EVOLUTION OF BOREAL LAKE SENSITIVITY TO UV RADIATION AND DOM
 
Dissolved organic matter (DOM) controls UV radiation (UVR) flux in lakes. Consequently, biota may experience their greatest UVR exposure immediately following deglaciation, prior to the development of Holocene DOM sources. Paleolimnological tests of this hypothesis with fossil pigments showed that UVR exposure was high, and algal abundance low, during the first millennium of boreal lake existence, but not during other periods. In contrast, UVR penetrated deeply into subalpine Crowfoot Lake whenever climatic cooling reduced treeline to below lake elevation. Comparison of alpine and low elevation sites suggested that post-glacial UVR penetration varied due to long-term changes in DOM influx, and that the DOM content of lakes regulated historical variance in algal abundance and gross community composition.
 
Day: Wednesday, Feb. 3
Time: 08:45 - 09:00am
Location: Sweeney Center
 
Code: CS65WE0845S