Introduction to the special section: Status and approaches to assess Lake Erie Central Basin hypoxia

Seasonal hypolimnetic hypoxia has occurred in Lake Erie’s central basin since at least the 1950s. The 2012 Great Lakes Water Quality Agreement includes a lake ecosystem objective that commits Canada and the United States to minimize the extent of hypoxic zones, with a particular emphasis on Lake Erie. To meet that objective, Canada and the United States adopted a 40% total phosphorus load reduction target for the western and central basins of the lake. To help assess progress in minimizing Lake Erie’s hypoxic zones, the Cooperative Institute for Great Lakes Research (CIGLR) convened a virtual summit in October 2021 to update the state-of-knowledge regarding hypoxia in Lake Erie. This special section summarizes the recommendations for monitoring, assessment, modeling and reporting of hypoxia that resulted from the workshop and features five papers that present new information about hypoxia in Lake Erie. Recognizing that hypoxia occurs in other areas within the Great Lakes basin, a paper investigating seasonal drivers of hypoxia dynamics in Muskegon Lake a drowned river mouth that flows into Lake Michigan, is also featured.