This summer’s Chesapeake Bay “dead zone” was the smallest it’s been since monitoring began in 1985, according to data released by the Chesapeake Bay Program’s monitoring partners: the Maryland Department of Natural Resources, Old Dominion University and Virginia Institute of Marine Science. 

The new measurements confirm the June 2023 Chesapeake Bay forecast, which predicted the smallest dead zone on record. The model used to make the annual forecasts was developed at the University of Michigan.

In June, a research team that includes University of Michigan School for Environment and Sustainability (SEAS) aquatic ecologist Don Scavia forecast that the 2023 Chesapeake Bay dead zone would be 33% smaller than the long-term average between 1985 and 2022, which would make it the smallest on record.

"It's nice to see that this year's forecast was accurate and that with the addition of each year, the model becomes more robust," said Scavia, a professor emeritus at SEAS.

Dead zones are areas of low oxygen that form in deep bay waters when the nutrients nitrogen and phosphorus enter the water through polluted runoff and feed naturally occurring algae. This drives the growth of algal blooms, which eventually die and decompose, removing oxygen from the surrounding waters faster than it can be replenished. This creates low-oxygen—or hypoxic—conditions at the bottom of the bay that limit habitat for crabs, oysters, fish and other wildlife.

Read the full press release on the Michigan News website.