Concerns up and down the food chain

Excerpt:

BRETON ISLAND, La. — As the oil spill from the Deepwater Horizon spreads across the Gulf of Mexico, environmentalists and government officials have been working frantically to protect shoreline habitat like this island in the Breton National Wildlife Refuge, eight miles off the coast of Louisiana.

Breton Island, with its hundreds of nesting birds, has been protected by orange booms, as have many other areas of delicate estuaries and wetlands.

But biologists are increasingly alarmed for wildlife offshore, where the damage from a spill can be invisible but still deadly. And they caution that because of the fluidity between onshore and offshore marine communities, the harm taking place deep at sea will come back to haunt the shallows, whether or not they are directly hit by the slick.

The gulf’s deeper water harbors 10 species of threatened sharks, 6 species of endangered turtles, manatees, whales and innumerable fish.