Bay dead zone expected to be larger this year

Heavier nutrient load from Susquehanna River is the culprit

Scientists predict the size of a dead zone in Chesapeake Bay this summer to be at nearly 1.9 cubic miles — larger than the average of 1.7 cubic miles recorded in the past three decades.

This year’s dead zone is equivalent to 3.2 million Olympic-size swimming pools, according to a press release from the University of Maryland Center for Environmental Science.

Dead zones, also known as hypoxic zones, are caused by excessive nutrient pollution, primarily from human activities such as agriculture and wastewater, according to the National Oceanic and Atmospheric Administration.

Excessive nutrients can stimulate an overgrowth of algae, which then sinks and decomposes in the water. That process uses oxygen in the water, leaves areas of water with low oxygen and causes fish and other marine life to die or leave the area.

Scientists attributed this year’s higher-than-average dead zone size to above-average nutrient load from the Susquehanna River in New York and Pennsylvania this spring, the university’s release said.

“Although the higher forecasts for this summer seem to buck a recent trend toward lower anoxic volumes in Chesapeake Bay, they are consistent with known links between high river flows and oxygen depletion,” said Jeremy Testa, assistant professor at the University of Maryland Center for Environmental Science’s Chesapeake

The Susquehanna River carried more than 80 million pounds of nitrogen into the bay, slightly larger than the long-term average, the release said.

The anoxic portion of the zone, which contains no oxygen at all, is expected to be 0.35 cubic miles in early summer, growing to be 0.49 cubic miles by late summer, the release said. Both of which are at or slightly above average.

“The forecast is a reminder that the improvements such as we saw last year are subject to Biological Laboratory. reversal depending on weather conditions,” said Don Boesch, president of the University of Maryland Center for Environmental Science, in a release. “Two steps forward, one step back.”

Monitory reports released earlier this year showed the bay’s health slightly improved.

“This underscores the critical importance of continued investments by federal agencies in science and monitoring as the states continue to implement the bay’s pollution diet,” Boesch said.