CS08 Biogeochemical Cycles
Date: Monday, June 10, 2002
Time: 2:30:00 PM
Location: Saanich
 
HatchLK, University of Minnesota, St. Paul, USA, hatch013@umn.edu
Asah, S, , University of Minnesota, St. Paul, USA, asah0002@umn.edu
Perry, J, , University of Minnesota, St. Paul, USA, jperry@umn.edu
 
SYMBIOTIC INVERTEBRATE/FUNGAL MUTUALISM IN A STREAM COMMUNITY STOICHIOMETRIC CONTEXT
image
While consumer-driven nutrient cycling has been useful in examining ecological stoichiometric relationships in lake environments, the flowing environment of streams would not be a good candidate for this approach. We are applying a more community-based approach to stoichiometry in four spring-fed streams in eastern Minnesota. The mutualism investigated is between stream invertebrates (primarily chironomids [midges]) and gut fungal symbionts (primarily Trichomycetes); this is somewhat analogous to the relationship between mychorrizae and terrestrial plants where the fungi assists the plant in attaining greater quantities of nutrients while the fungi gains organic carbon from its host. We are utilizing watercress (Nasturtium officinale), which we found to have differing nutrient contents and ratios in our streams. We have completed watercress transplant experiments and results will be presented. We hypothesize that the invertebrates from our four treatments will have differing invertebrate nutrient ratios, colonization rates, and watercress decomposition rates. Future work will include both field and laboratory experiments using laboratory-cultured watercress (resulting in a wider array of nutrient contents and ratios).