CS35 Trophic Dynamics
Date: Friday, June 14, 2002
Time: 9:00:00 AM
Location: Carson A
BeisnerBE, Center for Limnology University of Wisconsin-Madison, Madison, USA, bebeisner@facstaff.wisc.edu
Dent, C, L, Center for Limnology University of Wisconsin-Madison, Madison, USA, ldent@facstaff.wisc.edu
Carpenter, S, R, Center for Limnology University of Wisconsin-Madison, Madison, USA, srcarpen@facstaff.wisc.edu
In north temperate lakes, chlorophyll levels are affected by 3 main factors: phosphorus loading, dissolved organic carbon (DOC) and food web effects mediated through the size of zooplankton grazers. There is mounting evidence that chlorophyll levels may exhibit multiple stable states. We might expect therefore, that the distribution of mean chlorophyll across lakes would show a multimodal distribution. This is not the case in the north temperate landscape. To investigate how changes in land use and climate might affect future chlorophyll conditions in these lakes, we created a mechanistic model with alternative stable states based on P load, DOC and a cascading food web. The model predicts chlorophyll distributions, parameterized for the north temperate region. The goal was to understand the current distribution of chlorophyll across lakes in the landscape, and to predict the resiliency of the clear water state. Under current conditions of land and lake use, the model indicates that most lakes in the region are resilient clear water lakes. With changing conditions, more lakes could change to a high chlorophyll state that is costly to remediate.