ASSESSING BLOOM CONDITIONS ALONG A NORTH-SOUTH TRANSECT IN WESTERN LAKE ERIE DURING 2021-2023

Following improvement of the harmful algal bloom impairment in the 1970s, Lake Erie began experiencing re-eutrophication in the 1990s. Western Lake Erie (WLE) is subject to high nutrient inputs from the Maumee River and large, nutrient-poor discharge from the Detroit River. Our study explores how water quality and the phytoplankton community changed along a transect extending from the Detroit River mouth to near the Maumee River mouth. We sampled monthly May-October in 2021-2023 evenly spaced along the transect. In 2021, water quality parameters varied more spatially than monthly, particularly in August-October. During 2022, there was spatial and monthly variation, but water further along the transect was more variable temporally. In the later months of both years, chlorophyll, particulate organic carbon and nitrogen, total phosphorus, and suspended solids increased and ammonia decreased along the transect. In situ instrument-collected data revealed an increase in temperature and specific conductivity and more rapidly diminishing PAR with depth along the transect. FluoroProbe data revealed a continued presence of diatoms throughout 2021 with relatively low cyanobacteria concentrations in August-October, while 2022 saw a more typical succession of algal composition for WLE. These data echo differences between the two bloom years, which was more widespread but less concentrated in 2021 than 2022, possibly explained by precipitation patterns. Dynamics associated with the 2023 bloom will also be discussed to help elucidate spatial-temporal patterns of bloom conditions in WLE.

Primary Presenter: Jasmine Mancuso, Cooperative Institute for Great Lakes Research (mancusoj@umich.edu)

Authors:

Jasmine Mancuso, Cooperative Institute for Great Lakes Research  (mancusoj@umich.edu)

Ashley Burtner, NOAA Great Lakes Environmental Research Lab  (Ashley.Burtner@noaa.gov)

Andrew Camilleri, Cooperative Institute for Great Lakes Research  (accamill@umich.edu)

Kelly McCabe, Huron River Watershed Council  (kmccabe@hrwc.org)

Christine Kitchens, Planatir.net  (chknight@umich.edu)

Duane Gossiaux, NOAA Great Lakes Environmental Research Lab  (duane.gossiaux@noaa.gov)

Glenn Carter, Cooperative Institute for Great Lakes Research  (carterg@umich.edu)

Reagan Errera, NOAA Great Lakes Environmental Research Lab  (reagan.errera@noaa.gov)

Casey Godwin, Cooperative Institute for Great Lakes Research  (cgodwin@umich.edu)