The low-oxygen “dead zone” in the Chesapeake Bay will be markedly smaller this summer than its long-term average size, said a team of researchers on Tuesday. The scientists said the forecast was the latest sign that efforts to reduce nutrient runoff into the bay were paying off.
“In addition to this year’s forecast, the measured dead zone has been below the long-term average in eight of the past 10 years,” said Dan Scavia, aquatic ecologist at the University of Michigan. The dead zone, where there is too little oxygen for marine life, was forecast to be 13 percent smaller than the long-term average.
Researchers said the hypoxic zone would be smaller because of a below-average volume of water entering the bay from its tributaries in the spring and a decline in sediment and nutrient pollution from jurisdictions in the watershed. In addition, they said the dead zone began to form later than usual because of cool weather during May.
“The Bay is trending in the right overall direction, but it still has a long way to go—a hill made much steeper due to climate change,” said Beth McGee, director of science and agricultural policy at the Chesapeake Bay Foundation. She said continued funding from USDA was needed so that farmers could reduce nutrient runoff from their land. McGree said the EPA “must hold the states, especially Pennsylvania, accountable to meet pollution reduction requirements from all sources.”
States in the Chesapeake Bay watershed agreed in 2010 to reduce nitrogen, phosphorus and sediment pollution entering the bay, with a 2025 deadline to adopt policies to reach their targets for reduction.
The foundation says the Chesapeake Bay dead zone covers from 0.7 to 1.6 cubic miles of water during the summer, when its water is warmest and oxygen levels are lowest.