June 2021 Chesapeake Bay Hypoxia Report
Best ever recorded dissolved oxygen for early June
Data collected by the Maryland Department of Natural Resources (DNR) and Old Dominion University show dissolved oxygen conditions in the main arm of the Chesapeake Bay of Maryland and Virginia were better than average in June 2021 The hypoxic water volume – areas with less than 2 mg / l oxygen – was 0.21 and 1.28 cubic miles during surveillance cruises in early and late June, compared to historical averages in early and late June ( 1985-2020) of 0.89 and 1.31 cubic miles. The early June report is the best ever, and the end of June was slightly better than average.
Additionally, in the hypoxic waters of Maryland’s main branch at the end of June, 0.26 cubic miles were anoxic – areas with less than 0.2 mg / L oxygen. Anoxia was not present in the analysis at the end of June since 2014.
As of this year, Maryland and Virginia present combined results for the mainstream of the bay, in order to be more comparable to the annual seasonal forecasts by the Chesapeake Bay Program of the United States Environmental Protection Agency, the US Geological Survey, the Center for Environmental Sciences at the University of Maryland and the University of Michigan.
End of June, this provide predicted hypoxic volume of the mainstem Chesapeake Bay 14% lower than the 35-year average due to reduced river flows from January to May 2021, as well as less nitrogen transported into the bay due to efforts to nutrient management. Monitoring results from Maryland and Virginia so far have met expectations of better than average conditions.
Crabs, fish, oysters and other creatures of the Chesapeake Bay need oxygen to survive. Scientists and natural resource managers are studying the volume and duration of bay hypoxia to determine possible impacts on bay life.
Each year from June to September, the DNR collects these volumes from the Maryland Bay portion and compiles them with data collected by the Virginia Department of Environmental Quality.
Data collection is funded by these states and the Chesapeake Bay Program. Bay hypoxia monitoring and reporting will continue throughout the summer. More data and information on Maryland water quality, including the hypoxic volume of the DNR calculation methods, can be found at DNR The site of eyes on the bay.