Natural Buffers Took a Beating

Experts suspect the hurricane has swamped everything from oyster beds to the sea grass that provides a critical nursery for fish, and the flush of nutrients from sewage-laden water into the gulf could spark massive algae blooms deadly to marine organisms.

"What we're looking at here is too much of a good thing," said Hans W. Paerl, professor of marine and environmental sciences at the University of North Carolina at Chapel Hill, citing the nutrient influx. "And what is the impact of those pollutants that are coming in, I don't think we know very well at all."

Congress plans to examine the question soon: Rep. Paul E. Gillmor (R-Ohio), who chairs the House Energy and Commerce subcommittee on environment and hazardous materials, will start hearings at the EPA's "earliest convenience," said his spokesman Brad Mascho.

Scientists and local advocates are particularly concerned about Lake Pontchartrain, which had begun to recover from decades of pollution. In recent years, it has become a commercial and recreational fishing locale, as well as a modest beach destination. Just this summer, lake visitors spotted manatees -- a large, endangered marine mammal that mainly lives in Florida -- in the lake's waters.

Rep. Bobby Jindal (R-La.), whose district encompasses the lake's entire north shore, said residents are worried the contaminants from New Orleans floodwaters will undo the progress made over the past decade.

"The tragedy is, as you drain the city, there is no good alternative to taking that water and putting it back into the lake," Jindal said.

Duke University environmental engineering professor Karl G. Linden said that while he understood that dumping polluted water into Lake Pontchartrain is the "lesser evil" -- compared with pumping it into the Mississippi River or the Gulf of Mexico, federal and state officials need to do a better job of treating the water first.

"There's got to be ways we can treat it without pumping it out raw," Linden said. EPA tests, he added, showed some of the industrial floodwaters are "as toxic as a toxic waste dump."

In addition to unleashing toxic and human refuse, the hurricane destroyed habitat critical to area wildlife. The storm hurt 25 national wildlife refuges that will cost at least $93 million to repair, according to preliminary estimates, a figure equal to a quarter of the entire federal budget for the refuges. Sixteen are temporarily closed.

In Mississippi's Noxubee National Wildlife Refuge, the hurricane felled pine trees crucial to the survival of the endangered red-cockaded woodpecker; Breton Island, a sanctuary for nesting and wintering seabirds and shorebirds, has largely washed away.

"It's going to damage things," said Cathy Shropshire, executive director of the Mississippi Wildlife Federation.

Steve Cochran, a Louisiana native who now works as a senior staffer at the advocacy group Environmental Defense Fund, said the hurricane dealt the final blow to flora and fauna that have declined for decades because of habitat loss.

"All of those things, entirely unique to that part of the world, have been disappearing since about, say, 1927, and now they've disappeared altogether," Cochran said, recalling swamp lilies he used to find right outside New Orleans. "Too few people have experienced them, and now, no one else will."

Researcher Meg Smith contributed to this report.