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POTENTIAL FACTORS REGULATING PRIMARY PRODUCTION IN THE WESTERN BASIN OF LAKE ERIE, EXAMINED USING TEMPORAL COMPARISONS AND GENERALIZED LINEAR MODELS (E)

Eutrophication in freshwater resources is a critical threat to both human and ecosystem health. In response to eutrophication in Lake Erie in the 1960s, target total phosphorus loadings of 11 000 metric tonnes per annum were met by the mid-1980s, corresponding with a decrease in chlorophyll a (chl a ) and phytoplankton biomass concentrations. However, primary production has not been consistently measured over the same period. Since the mid-1990s, cyanobacterial blooms have reappeared in the western basin of Lake Erie, leading to further questions regarding the drivers of these blooms. In the summer of 2014 and 2015, primary production, chl a and phytoplankton biomass were measured at a nearshore and offshore site in the western basin of Lake Erie. When compared to historical studies, chl a decreased significantly from an average of 12.6 mg / m3 in 1970 to 3.6 mg / m3 in 2015, while primary production and biomass did not significantly change over the same period (annual averages ranged from 26.5 to 25.6 mg C / m3 / h for primary production and 3.5 to 1.6 g / m3 for biomass), despite decreases in total phosphorus loadings. Generalized linear models (GLMs) found that while depth, water temperature and chl a were always included as regulating factors of primary production in 2014 and 2015, total phosphorus concentrations (TP) were never included. This suggests that other factors besides TP must be considered as potential regulators of primary production in the western basin of Lake Erie.

Authors

Hillis, E. L., University of Windsor- GLIER, Canada, hillise@uwindsor.ca

McLeod, A. M., Memorial University of Newfoundland, Canada, mcleod15@uwindsor.ca

Xenopoulos, M. A., Trent University, Canada, mxenopoulos@trentu.ca

Haffner, G. D., University of Windsor- GLIER, Canada, haffner@uwindsor.ca

Details

Oral presentation

Session #:021
Date: 03/02/2017
Time: 10:15
Location: 323 B

Presentation is given by student: Yes