Spatial Variation of Primary Production and Chlorophyll a in the Three Basins of Lake Erie
Erin Hillis, University of Windsor- GLIER, [email protected]
Marguerite Xenopoulos, Trent University, [email protected]
G. Doug Haffner, Great Lakes Institute, Univ. of Windsor, [email protected]
Abstract
Primary production and phytoplankton biomass are important limnological measurements for both eutrophication and fisheries management. In 1970, volumetric primary production (PPvol) and chlorophyll a (chl a) were higher in the western basin of Lake Erie compared to the central and eastern basins. However, later reductions in phosphorus loadings and the invasion of dreissenid mussels may have impacted phytoplankton dynamics. The objective of this study was to compare PPvol and chl a both between nearshore and offshore sites and among the three basins of Lake Erie in 2014 and 2015. For both variables, there was no significant difference between nearshore and offshore sites in all basins, or among the basins at nearshore sites. However, at offshore sites, both PPvol and chl a were higher in the western basin (22 mg C m-3 h-1 and 4.4 mg m-3, respectively) and central basin (24 mg C m-3 h-1 and 3.6 mg m-3) compared to the eastern basin (10 mg C m-3 h-1 and 1.3 mg m-3). The relatively high PPvol and chl a in the central basin differs from 1970, when the western basin was more productive and higher in chl a, which should be considered in future central basin hypoxia models.
1. Keyword
productivity
2. Keyword
Lake Erie
3. Keyword
eutrophication