For an August 2016 update on the Chesapeake Bay “dead zone,” please see this Water Central News Grouper post of 8/25/16.
On June 13, 2016, federal and state scientists working on the Chesapeake Bay announced the prediction for 2016 of the so-called “dead zone” in the Bay—that is, the expected area of “hypoxia,” where the dissolved oxygen levels are below 2 milligrams per liter of water, too low to support the Bay’s normal community of organisms. The maximum volume affected by mid-summer is predicted to be approximately 1.58 cubic miles, close to the long-term average as measured since 1950. Meanwhile, on June 9 scientists predicted that the Gulf of Mexico “dead zone” will be 5.9 square miles, about the average of the past several years, according to the U.S. Geological Survey (USGS).
More details on the Chesapeake Bay “dead zone” prediction are given below in an excerpt from the USGS’s 6/13/16 news release, NOAA, USGS and partners: Chesapeake Bay ‘dead zone’ to vary from average to slightly smaller. The “dead zone” prediction for the Gulf of Mexico in 2016 is contained in the following June 9, 2016, news release from USGS: NOAA, USGS and partners predict an average ‘dead zone’ for Gulf of Mexico.
For “dead zone” predictions from previous years, plus access to various annual “report cards” of dissolved oxygen and other conditions in the Bay and several tributaries, see the “Ecocheck” Web site provided by the University of Maryland/Center for Environmental Science, online at http://ian.umces.edu/ecocheck/forecast/chesapeake-bay/2015/.
Excerpt from 6/13/16 USGS news release on the Chesapeake Bay “dead zone” prediction: “The anoxic portion of the zone, which contains no oxygen at all, is predicted to be 0.28 cubic miles in early summer, growing to 0.31 cubic miles by late summer. Low river flow and low nutrient loading from the Susquehanna and Potomac rivers this spring account for the smaller predicted size of the anoxic portion. The Bay’s hypoxic and anoxic zones are caused by excess nutrient pollution, primarily from human activities such as agriculture and wastewater. The low oxygen levels are insufficient to support most marine life and habitats in near-bottom waters and threaten the Bay’s production of crabs, oysters and other fisheries. The predicted ‘dead zone’ size is based on models that forecast three of its features: midsummer low-oxygen hypoxic zone, early-summer oxygen-free anoxic zone, and late-summer oxygen-free anoxic zone. The models were developed by NOAA-sponsored researchers at the University of Maryland Center for Environmental Science and the University of Michigan. They rely on nutrient loading estimates from the U. S. Geological Survey.”