SHELL BEACH, La. ��" Battered by hurricanes, weakened by erosion and flood-control projects, the sprawling wetlands that nurture Gulf of Mexico marine life and buffer coastal cites from storm surges now face another stern test as a monster oil slick creeps ever closer. About 40 per cent of the nation's coastal wetlands are clumped along southern Louisiana, directly in the path of oil that was still gushing onMonday from a ruptured underwater well. Roughly 3.5 million gallons has escaped in the three weeks since an oil rig explosion, and some is bearing down on the marshes as workers rush to lay protective boom. "No question we will see some widespread impacts," Garret Graves, theChairman of the Coastal Protection and Restoration Authority of Louisiana, said after an observation flight. "If we allow this oil to get into our coastal areas and fundamentally change the ecosystem, the consequences are profound." Removing oil from wetlands is a huge challenge. Bulldozers can't simply scrape away contaminated soil, as they do on beaches. Cutting and removing oil-soaked vegetation could further weaken the fragile vegetation that holds the marshes together. Absorbent materials and detergents have limited effectiveness, Graves said. If a thick enough layer of oil coats hardy swamp grasses and shrubs, scientists say it could shut down their equivalent of breathing - absorbing carbon dioxide and releasing oxygen. "You could literally suffocate the marsh," said Alex Kolker, a coastal systems specialist with the Louisiana Universities Marine Consortium. Even worse, the oil could soak into the ground and poison roots, killing entire plants. With nothing to anchor it, the soil would wash away, accelerating a process that has cost Louisiana about 2,300 square miles of coastal marshes and barrier islands the last 80 years ��" an area bigger than Delaware. A spill-related loss of wetlands would ripple through the food chain they support, from tiny organisms to fish and birds. "It's like you pull a thread on the shirt and it all comes apart," said Mark LaSalle, an ecologist at the Pascagoula River Audubon Centre in Moss Point, Miss. Or the damage could be less severe and the ecosystem could survive yet again.
