December 2, 2023 — The “dead zone” in the Chesapeake Bay is the smallest it has been since recording began in 1985, according to new data from Maryland Department of Natural Resources, Old Dominion University and Virginia Institute of Marine Science.
The dead zone is the area in which there is a relative low amount of oxygen, a condition known as hypoxia. Typically, this means that polluted runoff has brought in phosphorus and nitrogen, which feeds growth of algal blooms. These blooms eventually die and decompose, removing oxygen from the surrounding waters faster than it can be replenished. Animals such as crabs, oysters and fish need healthy levels of oxygen in the water to survive.
The Maryland Department of Natural Resources reported dissolved oxygen levels in the Chesapeake Bay were “much better” than past years. The department reported the dead zone averaged 0.52 cubic miles from May to October this year, compared with the historical average of 0.97 cubic miles.
VIMS reported a dead zone of 0.58 cubic miles. The institute reported that hypoxia began earlier than usual, in April, but it remained “uncharacteristically low” from June until ending in late-September. The relatively early end resulted from cooling temperatures in September and strong winds during Tropical Storm Ophelia.