Vinebrooke, R. D.. Department of Biology, University of Regina, rolf@ualberta.ca
Leavitt, P. D.. Department of Biology, University of Regina, leavitt@uregina.ca

 
ALPINE LITTORAL FOODWEB RESPONSES TO ALLOCHTHONOUS DISSOLVED ORGANIC MATTER, INORGANIC NUTRIENTS, AND ULTRAVIOLET RADIATION: POTENTIAL IMPACTS OF CLIMATIC WARMING
 
Climatic warming can promote soil and vegetation development in alpine environments, which should increase allochthonous inputs of ultraviolet radiation (UVR)-attenuating dissolved organic matter (DOM and inorganic nutrients (NP) to treeline lakes and ponds. A 3-factor (DOM X NP X UVR) experiment was conducted using 24 enclosures to address the potential impact of climatic warming on an alpine littoral foodweb. DOM amendments significantly increased epilithon abundance (P<0.01) and the final abundance of copepod nauplii (P<0.01). NP additions also significantly enhanced epilithon abundance (P<0.001) and the development of epipelon (NP-time interaction; P<0.05) by stimulating diatoms. NP only affected phytoplankton by reducing the relative abundance of picocyanobacteria. Ambient UV irradiance enhanced the positive effect of DOM on epilithon (DOM-UVR interaction; P<0.05) and stimulated epipelon abundance (P<0.05). An altitudinal survey of 20 mountain lakes and ponds corroborated these experimental results, showing that phytobenthos abundance and community composition are strongly associated with climate and catchment-related variables. These findings suggest that climatic warming will alter littoral food-web structure in treeline lakes and ponds by selectively promoting benthic over planktonic processes.
 
Day: Monday, Feb. 1
Time: 02:15 - 02:30pm
Location: Hilton of Santa Fe
 
Code: SS14MO0215H