SS3.09 Climate-Lake Interactions
Date: Wednesday, June 12, 2002
Time: 10:30:00 AM
Location: Colwood
 
MichelTJ, University of Wisconsin-La Crosse, La Crosse, USA, timmy09@hotmail.com
Saros, J, E, University of Wisconsin-La Crosse, La Crosse, USA, saros.jasm@uwlax.edu
Interlandi, S, J, Drexel University, Philadelphia, USA, inters@drexel.edu
Wolfe, A, P, University of Alberta, Edmonton, CANADA, awolfe@ualberta.ca
 
POSSIBLE LINKS BETWEEN INCREASED PRECIPITATION AND SHIFTS IN DIATOM COMMUNITY STRUCTURE IN ALPINE LAKES
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Alpine lakes are sensitive systems that respond rapidly to climate change. This response is often complex and unique to a particular region. Over the past century, the Beartooth Mountain Range (MT/WY), has experienced an increase in precipitation, primarily in the form of snowfall. Higher precipitation rates have increased the deposition of atmospheric nitrogen and may have altered weathering rates of silica and phosphorus from the watershed, resulting in shifts in resource ratios in lakes of this area. Diatom profiles from lacustrine sediments in the area indicate recent shifts in diatom assemblages from species typical of alpine systems to those often associated with mesotrophic and/or eutrophic systems. We suggest that these species shifts are linked to changes in resource ratios in these systems, thus we conducted a series of in situ culturing experiments to quantify the nutrient requirements of several diatom taxa. Preliminary results indicate previously dominant small Fragilaria species have the lowest nitrogen and phosphorus requirements. In contrast, species that have increased in abundance such as Fragilaria crotonensis and Tetracyclus glans have higher requirements for nitrogen, phosphorus, and silica.