A new study shows that dead zones in the lower Chesapeake Bay are beginning to break up earlier in the fall, which may be an indication that efforts to reduce nutrient pollution to the Bay are beginning to make an impact. Scientists from the University of Maryland Center for Environmental Science examined 30 years of data on dead zones and nutrient levels in the Chesapeake Bay. They found that dead zones in the lower part of the Chesapeake Bay, the saltier part from the Potomac River south, are getting smaller in the late summer thanks to a late-season replenishment of oxygen, a natural response to decreasing nutrient pollution.
“This study shows that water quality monitoring programs that have been in place for decades are beginning to reveal fundamental information on the nature of change associated with the Chesapeake Bay’s dead zones,” said Peter Goodwin, president of the University of Maryland Center for Environmental Science. “These areas are beginning to undergo recovery from eutrophication, and even more exciting, natural responses to cleaning the water are kicking in.”
Dead zones, areas of low to no oxygen that choke off life in the Bay, typically start growing in late May and dissipate in the fall. Studies in the past decade have shown that the size of the dead zone changes throughout the summer, growing larger in June and smaller in August. Jeremy Testa and his team, including UMCES Professors Emeriti Walter Boynton and Michael Kemp, set out to understand what was happening late in the season. They found that a complex chemical process was kicking in, allowing the Bay to begin cleaning itself.
Read more at University of Maryland Center for Environmental Science