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Ecological modeling of the lower trophic levels of Lake Erie
Zhang, Hongyan

2006, Doctor of Philosophy, Ohio State University, Evolution, Ecology, and Organismal Biology.
Lake Erie is facing many perturbations. This study focuses on two issues, the external phosphorus loading and dreissenids’ invasion, and investigates the interactions of the responses of the lower trophic levels to these two stressors. I construct an ecological model, EcoLE, based on a USEPA two-dimensional hydrodynamic and water quality model, CE-QUAL-W2. Data from the field year 1997 are used to calibrate the model, while data from 1998 and 1999 are used for verification. There is a good agreement between the modeled and field-measured state variables, and EcoLE catches the major characteristics of the physical, chemical and biological processes found in Lake Erie. We are confident in using this model for qualitative analysis, but one should be cautious in using it for quantitative predictions of Lake Erie processes. When I turn off the turbulent mixing processes, total dissolved phosphorus (TP-F) becomes concentrated in the lower water strata and diatom biomass decreases dramatically. When I turn on the mixing processes again, there is more TP-F in the upper water strata but less TP-F accumulated in the whole water column, because non-diatom edible algae (NDEA) and diatoms become more abundant in the water column. Blue-green algae are less affected by hydrodynamics but depend on the amount of available phosphorus in the whole water column. When I turn off the chemical and biological processes, external TP loads are distributed throughout the western basin and the west central basin as a result of physical mixing. External TP loads have minor direct effects on the east central and the eastern basins, where up to 60% of the daily algal P-demands come from SRP released by organic matter decomposition and by algal and crustacean P excretion. Dreissenid mussel daily grazing impact is less than 10% of the NDEA and diatom biomass in the western basin, and only 1-2% in the central and eastern basins. Impacts of dreissenid nutrient excretion become more important than the grazing impact with an increase in mussel population size.
David Culver (Advisor)
246 p.

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Zhang, H. (2006). Ecological modeling of the lower trophic levels of Lake Erie. (Electronic Thesis or Dissertation). Retrieved from https://etd.ohiolink.edu/

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Zhang, Hongyan. "Ecological modeling of the lower trophic levels of Lake Erie." Electronic Thesis or Dissertation. Ohio State University, 2006. OhioLINK Electronic Theses and Dissertations Center. 01 Apr 2015.

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Zhang, Hongyan "Ecological modeling of the lower trophic levels of Lake Erie." Electronic Thesis or Dissertation. Ohio State University, 2006. https://etd.ohiolink.edu/

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