New York undertakes an oyster restoration project to clean water

Posted on 01. Dec, 2010 by Sherry Mazzocchi in Uncategorized

Oysters are returning to Jamaica Bay. But don’t expect to dine on them anytime soon. These shellfish are an ‘ecological services’ experiment. Oysters filter somewhere between 25 to 50 gallons of water a day. Scientists think their filtration powers can help clean troubled waters.

Jamaica Bay can use the extra help. Four wastewater treatment plants release an average of 40,000 pounds of nitrogen into the bay every day.  Excess nitrogen is linked to algae blooms–toxic conditions that cause fish kills– and the loss of wetlands in the bay.

The Jamaica Bay site is only part of a $1.3 million project that includes five other New York sites. The project is a collaboration of The Hudson River Foundation, NY/NJ Baykeeper, The Army Corps of Engineers and 18 other educational and environmental groups.

By 2015, they hope to establish 500 acres of oysters around New York. Their ultimate goal is restoring 50,000 acres by 2050.

Not only do oysters filter and clean water, their reefs provide a habitat for other aquatic species as well. Meredith Comi, oyster restoration program director for the NY/NJ Baykeeper, said, “We’re looking at reefs as ecosystems services.”

Oysters are also touted for their ability to reduce nitrogen from the water and also sequester carbon dioxide. But some people aren’t so sure.

Chester Zarnock and Timothy Hoellein are scientists conducting independent research in Jamaica Bay. Zarnock, a biologist from Baruch College, studies shellfish. Hoellein, from Loyola University, studies the effects of nitrogen in sediment.

“Oysters can improve the water quality in estuaries. But we want to test whether or not oysters can influence the nitrogen cycling,” said Zarnock.

“Everyone says it can,” Hoellein said. “We just don’t know if it’s true.”

Zarnoch’s early tests show that oysters don’t filter as much water when there is a high algae count. Instead, they shut down.

“It’s too much for them,” said Zarnoch. “They get a lot of bank for their buck. An hour or so of feeding brings in so much food that they don’t need anymore.”

What happens in the sediment is also a mystery and Hoellein and Zarnoch want to find out. Nitrogen processed by oysters could turn into inert gas and be harmlessly absorbed in the atmosphere. Or it could be released into sediments, impacting tiny microorganisms and changing the ecosystem in unforeseen ways.

Comi said scientific research is another benefit of the project. “What do we really know about how much nitrogen they take out?” she said. “We know a lot about the basics of oysters.”

Oysters thrived in New York a century earlier, before succumbing to poor water quality and over-harvesting.  Scientists are learning the art of restoration in an urban environment. “The system is completely different than 100 years ago,” Comi said. The coastline and the currents are all different.”

Every state on the eastern seaboard, except New Jersey, has an oyster restoration project.  The state was a partner in the Baykeeper’s program until this summer. The New Jersey DEP ordered the oysters removed from Raritan Bay, fearing unwary citizens would poach them.

Comi said other states have effective prevention measures in place—ranging from a high-tech surveillance system in Chesapeake Bay to Shellfish Constables who patrol New England’s reefs.

A huge restoration project is years away, but Comi thinks it’s possible that oysters will eventually be incorporated in public works projects to clean New York’s water.

Since 2002, the city spent $6 billion for water quality improvement projects, according to John McLaughlin, director of ecological services at New York’s Department of Environmental Protection.

Speaking at the Metropolitan Waterfront Alliance in late November, McLaughlin said that, unlike large infrastructure projects like wastewater treatment plants, oysters have ancillary benefits. “They work 24/7. They don’t request overtime. They don’t go on strike.”