Chesapeake Bay dead zone measures slightly below average in 2015

The Maryland portion of the Chesapeake Bay dead zone measured slightly smaller than average this past summer, supporting scientists’ June prediction of a smaller than average hypoxic zone in the nation’s largest estuary.

Dead zones are areas of little to no dissolved oxygen that form when nutrient-fueled algae blooms die and decompose. This decomposition process removes oxygen from the surrounding waters faster than it can be replenished, and the resulting low-oxygen conditions can suffocate marine life.

Each summer, the Maryland Department of Natural Resources (DNR) and the Virginia Department of Environmental Quality (DEQ) collect water samples to measure the hypoxic volume of the Bay. At 3,806 million cubic meters, the Maryland portion of this year’s dead zone was the 13th smallest in 31 years of sampling.

According to a report from the DNR, the size of the dead zone was likely due to reduced rainfall earlier this spring.