- The Washington Times - Thursday, May 12, 2005

ANNAPOLIS — At this time of year, the waters of the Potomac River appear tranquil and unravaged by the pollution that lurks under the surface.

A month from now, as the water warms, the phytoplankton that grows naturally in the river will feast on toxic nitrogen and phosphorus that flows in daily from sewage pipes, streets and farm fields.

As it feeds, the algae blooms into a sprawling shield that suffocates the water and the marine life underneath.

This year, the blooms are expected to thrive.

State scientists, who for the first time are predicting how the blooms will behave, said yesterday that this summer could rank among the five worst for oxygen-deprived water in 20 years.

Scientists and ecologists are starting their studies on the Potomac, where they forecast a 10-mile-wide bloom beginning in early June that could last for 21/2 months.

On a graphic distributed at a press conference yesterday, the predicted bloom appears about halfway up the river.

“We’re trying to predict the location, timing, duration and the extent of this bloom,” said Peter Tango of the Maryland Department of Natural Resources (DNR).

They attribute the poor water quality, which is forecast to be moderate to severe this year, to heavy rainfall since January.

Rain washes pollution and sediment into the Bay and its creeks and rivers. A cool, dry or windy summer could help abate the blooms.

“We’re not going to guarantee what’s going to come,” said project leader William Dennison of the University of Maryland Center for Environmental Science. “We’re going to do a scientifically sound estimate of what’s going to occur using the best science we can muster.”

The idea is to use the predictions, which researchers compared to a weather forecast, to better target their restoration projects — such as underwater grass plantings and oyster reef rehabs.

State resource managers won’t waste time trying to beef up decimated reefs or grass beds in areas where the young have no chance of survival, DNR officials said.

The research doesn’t predict where fish kills might occur, but does tell them where fish are likely to flee. Crabs and clams can survive on less dissolved oxygen, but rockfish need more.

Areas with low oxygen levels essentially squeeze fish such as striped bass out of their usual habitats, forcing them to crowd into healthier waters.

A team of scientists from the University of Maryland and DNR is making the predictions, based on the amount of sediment, pollution and oxygen in the water.

The team thinks the research may be the first of its kind in the world, because most studies are conducted after an algae bloom occurs.

To help improve water quality, the university system’s cooperative extension service recommends homeowners put off fertilizing their lawns until fall.

Other measures that stave off pollution are conserving electricity and water and reducing driving.

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