An urban marsh’s unfinished saga
New York’s Jamaica Bay serves as a microcosm for the world’s wetland woes.
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The DEC has asked New York City’s Department of Environmental Protection (NYCDEP) to address Jamaica Bay’s water quality. In response, the DEP proposed a list of solutions in the 2007 Jamaica Bay Watershed Protection Plan. Among other things, the list included upgrading wastewater-treatment plants to reduce the nitrogen load. But “there’s basically been a backsliding” since then, says Brad Sewell, senior attorney with the Natural Resources Defense Council in New York.Skip to next paragraph
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Citing the failure of limiting nitrogen in halting marsh degradation in places like Long Island Sound, a more recent NYCDEP white paper obtained by the Monitor seems to deemphasize this approach, which, it estimates, could cost city residents $6 billion.
“Nitrogen levels have not been linked to marshland disappearance,” it states. “Upgrades will not attenuate this loss.”
But scientists have several working hypotheses explaining how excess nutrients may, in fact, harm wetlands. One is by making life too easy for the marsh grasses. “When plants get enough nutrients, they don’t produce as many roots,” says Dr. Turner. “When the storms come, they don’t have enough roots to hold the soil.”
Nutrients also spur algal blooms. When the algae dies, bacteria consume it and suck up oxygen. The story doesn’t end there, however. Another class of bacteria goes to work in these low oxygen areas. They use sulfates, a salt abundant in seawater, rather than oxygen to break down plant matter. And instead of exhaling carbon dioxide, they give off hydrogen sulfide. “That hydrogen sulfide is toxic to marsh plants in high concentrations,” says Alex Kolker, a research assistant professor at Tulane University in New Orleans. Spartina alterniflora, the dominant marsh grass here, can tolerate some sulfide, but “if you exceed the limits of its tolerance, it will die,” he says.
Help from oysters
Several restoration projects are already under way in Jamaica Bay. A pilot project is in the works to reintroduce oysters, absent since the 1930s. A single adult oyster can filter up to 50 gallons of water daily, clearing algae from the water.
“We know we can get them to survive,” says John McLaughlin, NYCDEP’s director of ecological services. “The next step is, can we get them to reproduce.”
Beginning in 2004, government agencies including the National Park Service and the Army Corps of Engineers planted spartina on hassocks fortified with dredged sand. Four years later, the restoration effort is considered a success. But ongoing losses are greater than what’s being restored. Without addressing the underlying causes of degradation, restoration efforts may not be sustainable in the long term, says Sewell.
Given the accelerating loss, some say there’s little time to waste. “We can’t just afford to let it go and not try to take all reasonable actions to keep it healthy,” says Mr. Swanson. “It may cost us in the short term, but [it’s] worth it in the long term.