Danielsdottir, M. G. University of Washington, martag@u.washington.edu
Brett, M. G. University of Washington, mtbrett@u.washington.edu

 
A MATHEMATICAL ANALYSIS OF FOOD QUALITY IMPACTS ON TROPHIC COUPLING
 
Recent analysis show high variability in the strength of food-web interactions in planktonic ecosystems, and several authors have suggested this is due to variation in food quality at the plant herbivore interface. We used a Lotka-Volterra modeling approach to test the hypothesis that variation in phytoplankton food quality may be a determinant of the strength of trophic interactions. The quasi-equilibrium zooplankton to phytoplankton biomass (Z/P) ratio was calculated as an index of the potential strength of trophic interactions. The model was run with the zooplankton growth efficiency varying from 4% to 64%. The Z/P ratio varied exponentially with the growth efficiency. Although the zooplankton community becomes somewhat self-limiting at high zooplankton biomass, high algal food-quality allows the zooplankton community to sustain a very high biomass at high growth efficiencies. These results indicate that the food-quality of the phytoplankton can dramatically affect the strength of trophic coupling and how phytoplankton production is transferred through the food web.
 
Day: Wednesday, Feb. 3
Time: Poster
Location: Sweeney Center
 
Code: SS21WE0636S