EASTON, MARYLAND — August dissolved-oxygen monitoring on the Chesapeake Bay mainstem showed a split month, the Maryland Department of Natural Resources said in a Sept. 18 release.

Data collected with Old Dominion University put early August hypoxic volume — water with less than 2 milligrams of oxygen per liter — at 0.67 cubic miles against a long-term average of 1.30 cubic miles. That ranked as the fifth-smallest early-August mainstem hypoxic volume in a 39-cruise comparison. Late August rose to 1.12 cubic miles, just above the 1.06 cubic mile average and ranking 28th of 42 cruises.

Early and late August each held 0.23 and 0.25 cubic miles of anoxia — water under 0.2 mg/l oxygen — less than July totals in the same release. Late July had ranked eighth-smallest at 1.08 cubic miles of hypoxia.

DNR tied the better-than-average stretch in part to persistent drought and lower river flow into the Bay, citing U.S. Geological Survey context that less freshwater can mean less nitrogen and phosphorus fueling algal blooms that later strip oxygen from deeper water. The Chesapeake Bay Program partners’ seasonal forecast, quoted in the release, said January–April 2026 river flow was 32% below the long-term average and nitrogen about 39% lower, totaling about 59 million pounds, with hypoxia volumes expected about 31% below average.

Crabs, fish, oysters, and other Bay life need dissolved oxygen. DNR computes hypoxia volumes each May through October from Maryland and Virginia monitoring funded with the Chesapeake Bay Program. Additional Maryland water-quality data sit on Eyes on the Bay. The release does not issue Talbot-specific hypoxia maps for August.