Subtle changes in Lake Erie water quality 2009-2018

Session: Great Lakes Tributaries: Connecting Land and Lakes (4)

Freya Rowland, Cooperative Institute for Great Lakes Research, University of Michigan, [email protected]
Craig Stow, NOAA Great Lakes Environmental Research Laboratory, [email protected]
Thomas Johengen, CILER, University of Michigan, [email protected]

Abstract

Despite extensive efforts to reduce phosphorus (P) loading to Lake Erie as part of the Great Lakes Water Quality Agreement, Lake Erie appears to be undergoing a re-eutrophication and is plagued by harmful algal blooms. Here we present an extensive dataset spanning 2009–2018 from 13 regularly monitored sites in the Western Basin to examine the recent trends in Lake Erie’s water quality and how they relate to Maumee River inputs. We found high but relatively stable in-lake concentrations of total P (TP) and soluble reactive P (SRP) with no discernable annual patterns. The Maumee River TP and SRP concentrations were higher than those observed in the lake, but similarly stable year-to-year. The lake sites closest and most-influenced by Maumee River water had the highest concentrations, whereas sites farther away and more influenced by Detroit River water were the lowest. We suggest within the Western Basin, the lake response is primarily determined by Maumee River water. The relationship between Chl a and TP was weakest closer to the Maumee as well, suggesting that lake water may not be as important as river water for determining algal biomass at sites closer to the Maumee River mouth.

Twitter handle of presenter
@freshwaterfreya