Study: Parts of Bay Cannot Support Life

A band of polluted water is choking aquatic life in the Chesapeake Bay, according to a survey that found oxygen absent from 10 percent of the estuary’s mainstem this month.

The ribbon of oxygen-less water follows the bay’s channel from roughly Deltaville to Annapolis, Md., and is the fourth-worst episode of anoxic conditions the Environmental Protection Agency survey has found in its 20-year-history, the EPA Chesapeake Bay office said yesterday. The worst year on record was 1993.

Cruises by Old Dominion University and the Maryland Department of Natural Resources from Aug. 8-11 also discovered that 41 percent of the bay’s mainstem contained less than 5 milligrams per liter of oxygen, which is not enough to support rockfish, shad and many of the bay’s finfish.

"We are removing 41 percent of the bay’s habitat," said Chuck Epes, spokesman for the Chesapeake Bay Foundation, an environmental group. "Anything less than 5 milligrams per liter is very problematic and, in the bay program’s own words, doesn’t have enough oxygen to support most living creatures."

Scientists said the combination of warmer water temperatures and an overabundance of nitrogen and phosphorous from sewage treatment plants, fertilizers, animal waste, air pollution and other sources caused oxygen levels to fall.

The band of bad water begins about 20 feet below the surface and extends to the bottom, said Chris Bonzek, a marine scientist at Virginia Institute of Marine Science. He conducts trawl-net surveys in the bay that measure fish abundance and said the oxygen-starved zone contains few fish.

"It’s depressing to be out there and be able to predict [whether the trawl will catch fish] based on our oxygen measurements," he said.

Bay program scientists had predicted that ample winter and spring rains would cause water-quality problems this summer. In 20 years of taking water samples, they have found that wet years flush nitrogen and phosphorous into the watershed, which fuels algae blooms that use up oxygen when the algae dies.

"Once water temperatures increased, that kicked algae decomposition into high gear," said Chris Conner, a bay program spokesman.

Virginia, Maryland and Pennsylvania have been working with the bay program for 20 years to combat the pollution problems. The region’s fast-growing population and related increase in roads, housing and sewage disposal are making the cleanup an expensive fight.

Former Va. Gov. Gerald L. Baliles chaired a commission last year that estimated it will cost $15 billion to restore the bay.

Virginia’s General Assembly created a study committee last winter that is examining how the state can finance its share of the costs. It is headed by Del. Vincent F. Callahan Jr., R-Fairfax.

"If people care that 41 percent of the bay is off-limits for fish, crabs and oysters, they should contact Delegate Callahan and urge him and his colleagues to fix this problem," Epes said.

He said bay foundation scientists recently found low oxygen conditions in the Rappahannock, York and James rivers and other tributaries of the bay that are not included in the EPA survey.

Low oxygen "is not just in the mainstem," Epes said, "it’s up the rivers — way up the rivers."