Modelling the impact of dreissenids and internal phosphorus loading in Lake Erie

Session: 31. - Evaluation of the Current State of Ecological Modeling and Future Perspectives

Meghan Brady, University of Toronto Scarborough, [email protected]
Zhuowei Xu, University of Toronto Scarborough, [email protected]
Alexander Lau, University of Toronto Scarborough, [email protected]
Yuko Shimoda, University of Toronto Scarborough, [email protected]
Ram Yerubandi, Environment Canada, Water Sciences & Technology, Canada Centre for Inland Waters, [email protected]
George Arhonditsis, University of Toronto Scarborough, [email protected]

Abstract

In many parts of the Laurentian Great Lakes, the arrival of dreissenid mussels has induced a major reengineering of the biophysical littoral environment with profound alterations on the retention and recycling of nutrients. This nearshore shunt is hypothesized to have modified the processing of particulate material in the littoral zones, with critical ramifications for their relative productivity and their interplay with the offshore areas. Depending on the concentration of food particles, dreissenid mussels can filter twice as much material as they actually ingest, and a large proportion is excreted in soluble form or released in particulate form as either feces or pseudofeces. It is thus hypothesized that dreissenids mediate the nutrient cycling and may significantly modulate the nearshore nutrient concentrations. In this regard, the structural adequacy of the nutrient mass-balance models developed during the pre-dreissenid period in the Great Lakes has been questioned. Our presentation reviews to what extent the eutrophication models developed for Lake Erie have properly reproduced the influence of dreissenids and sediment reflux rates on the biogeochemical cycling of the system. We evaluate the mathematical equations used, methodological practices followed, and lessons learned from these mechanistic models.

1. Keyword
ecosystem modeling

2. Keyword
Dreissena

3. Keyword
sediment load