JUDY WOODRUFF: Now, the American Gulf Coast a year later.
When the Deepwater Horizon oil rig exploded, the blast killed 11 workers. And after the rig sank, tens of thousands of barrels of oil spilled into the Gulf. That region is still trying to recover from the damage done to the environment.
NewsHour correspondent Tom Bearden returned to the Gulf to try to find some answers about the consequences.
TOM BEARDEN: The great marshlands of Louisiana are some of the most productive natural habitats in the world, teeming with wildlife. When the Macondo oil well blew out last year, many were afraid large parts of this ecosystem would be destroyed by the estimated 200 million gallons of oil that gushed out of the well.
There are a lot of different opinions among scientists and local residents about what the effects have been.
DAVE CVITANOVICH, oysterman: Look at this oil here. It looks like Like somebody poured paint. You have got that all the way around through here.
TOM BEARDEN: Last May, when Dave Cvitanovich showed us around Barataria Bay, he was worried the area wouldn't recover quickly. He's even more worried now.
DAVE CVITANOVICH: This is dying. This is a disease. This is the word -- a flesh-eating virus or something. That's what's happening here.
TOM BEARDEN: The bay is precious to Cvitanovich. He raises oysters in beds he leases from the state.
DAVE CVITANOVICH: It hurts. I mean, it just -- I have no formal education, a high-school education, but, you know, to look at these oyster beds that I have, I'm proud of the product that I sell. But I have leases that are worthless now.
You see over here?
TOM BEARDEN: Cvitanovich showed us deposits of oil in the marsh grass that have the consistency of candle wax.
DAVE CVITANOVICH: You see how it's greasy?
TOM BEARDEN: It's all stuck together, yes.
DAVE CVITANOVICH: Yes, sir. It's greasy. Look at my hand now. That's like a petroleum. You feel it?
TOM BEARDEN: It's clearly like -- it's not like the mud that just came apart.
DAVE CVITANOVICH: No. No, sir. No, sir.
TOM BEARDEN: This is...
DAVE CVITANOVICH: Because the mud had more a sand, a grit...
TOM BEARDEN: Right.
DAVE CVITANOVICH: ... whereas this here is like a -- like a baby oil.
TOM BEARDEN: He says it's killing the grass and dissolving the marsh. And that's a disaster in the making, because the marsh grasses are the breeding grounds for the oyster, shrimp, fish, and bird populations that are the foundation of the economy. Cvitanovich doesn't think the ongoing remediation efforts are working. He pointed out large tracts of grass that have died.
DAVE CVITANOVICH: Right now today, it's not choppy. But when bad weather comes, it eats this bank up more and more. It just erodes back.
TOM BEARDEN: Cvitanovich has a GPS device that is supposed to display the thousands of islands that dot Bay Jimmy.
DAVE CVITANOVICH: Yes, we're on land right now.
TOM BEARDEN: The database isn't that old, but we spent a lot of time cruising right through open water where the GPS showed land.
DAVE CVITANOVICH: There's a couple islands. I'm going to show you what's left of them. They're just some plastic pipes. And those islands were there when the oil spill occurred 11-and-a-half months ago.
TOM BEARDEN: So, in your lifetime alone, you have seen a lot of erosion?
DAVE CVITANOVICH: Oh, too much, way too much. You see where those pylons are?
TOM BEARDEN: Yes.
DAVE CVITANOVICH: That was an island. That was an island. That was a big island. They had a couple oyster camps there. People had grape trellises. They had trees. They had animals growing out there and everything else. And now it's just the few pylons left where that island was.
TOM BEARDEN: Mike Utsler, BP's chief operating officer for the Gulf Restoration Organization, insists the remediation being done is effective.
MIKE UTSLER, BP Gulf Coast Restoration Organization: We have worked many differing angles of efforts to identify the best way to accomplish a multitude of both cleaning and removing the residual oils, ensuring that migratory birds are not impacted by the potentials for flying in and trying to nest in those areas, and remove that residual hydrocarbon in a way that preserves and protects those marshes to allow them to regenerate.
This has been the most effective and best method, as agreed to by a wide range of environmental scientists.
TOM BEARDEN: Coastal erosion is nothing new in Louisiana. It's arguably the most serious environmental threat to the entire region.
What worries people here so deeply is whether or not oil in the marsh will cause it to happen that much more quickly.
Maura Wood is the senior outreach coordinator for the National Wildlife Federation's coastal Louisiana campaign. The organization has been studying the region for many years.
MAURA WOOD, National Wildlife Federation: We can't afford to lose any more land. And any of those marshes that received oil that are not growing back, don't have those plants helping to bind that soil together, are very much at risk of just being washed away by wind and tide and waves.
TOM BEARDEN: Ralph Portier is an environmental science professor at Louisiana State University. He says it will be a few years before a final assessment can be made on marshland impacts. But he says other effects will take even longer to surface.
RALPH PORTIER, Louisiana State University: I think, within the next three to four years, we will have a pretty good handle on everything near shore and in our marshes. It's going to be the deep ocean stuff. What's really happening in these deep coral reefs offshore near the Mississippi Canyon area? How were they affected? That story might take a decade to get an answer to.
TOM BEARDEN: A year later, there's still scientific debate about what's going on in the ocean itself. Some studies show the oil was mostly consumed by bacteria. Others suggest bottom-dwelling species have been suffocated by dead bacteria.
And then there's the issue of the almost two million gallons of the dispersant Corexit that were used. The EPA says the chemical has since degraded to nontoxic levels. But some scientists wonder about the long-term effects of low concentrations of Corexit.
RALPH PORTIER: Is there dispersant sitting in the bottom of the Gulf of Mexico in some of this oil? Is that going to be an avenue for a dispersant to start moving into the food chain or not? We don't know yet.
TOM BEARDEN: For its part, BP continues to try to clean up the remaining onshore oil.
MIKE UTSLER: We estimate that we have accomplished about 95 percent of the affected residual cleaning and removal of hydrocarbons across the areas from the Florida Panhandle to the Louisiana coastlines. We will be there as long as it takes to complete that last 5 percent.
TOM BEARDEN: The Coast Guard acknowledged today there's still oil coming ashore.
Coast Guard Rear Adm. Paul Zukunft.
REAR ADM. PAUL ZUKUNFT, Coast Guard: There are still tar balls that are offshore that are in those sand bars, and they break loose from time to time. They come ashore. And there are teams out there even today recovering those.
TOM BEARDEN: The area has been studied nonstop since the spill. Most results have not yet been made public, partly because of ongoing lawsuits.
But Maura Wood says there are some disturbing results that are known. In February, 36 premature or stillborn dolphins washed ashore, many times higher than normal.
MAURA WOOD: You see baby dolphins washing up dead. You see numbers of sea turtles beyond the norm, of endangered sea turtles, like the Kemp's ridley turtle. You see coastal marshes that are not growing back, that are black and dead and still covered with oil.
ACY COOPER, Louisiana Shrimp Association: All you have to do is stir the bottom up, it comes up. Like I did last year, show them, just go stir it up, and it pops up.
TOM BEARDEN: Acy Cooper says he knows there's a lot of oil still out there, despite government claims after the well was capped that most of it had dispersed and degraded.
ACY COOPER: It's there. How they going to clean it up? We don't know, because a lot of them, they don't know where it's at. And they won't go out there and actually find it. When you tell them where it's at, you don't hear nothing back. So, we don't know. We just don't know, the uncertainty of it all and not knowing is -- where it's at.
TOM BEARDEN: Cooper is the vice president of the Louisiana Shrimp Association. He and his two sons make their living on the water.
The men are getting their boats ready for the start of the shrimping season, and Cooper thinks they will probably have a pretty good catch this year. But he's concerned about how the oil might affect entire species of wildlife over the longer term, as it did after the Exxon Valdez.
ACY COOPER: Our concern is next year, the offspring from this crop. Will they come out fertile and will they come out deformed? You know, that's what happened in Alaska with the herring and the shrimp. We don't know what's going to happen in the future. So, it took two to three years before they really knew the effects of what it's going to be. And that's what we concerned about.
TOM BEARDEN: Portier hopes the scientific studies will help planning in the future.
RALPH PORTIER: There will be some rethinking of how oil companies respond to spills. So, I think we will have some things in place that will allow us to be a little bit more proactive than let's figure out where the oil is going, and let's let it go ashore, and then let's make decisions after the fact.
TOM BEARDEN: But he does fear one of the legacies of the BP spill will be a much smaller fishing industry if fishermen don't have a good season this year.
JUDY WOODRUFF: In his coming reports from the Gulf, Tom will report on the battle over compensation and the anger that remains toward BP and the government.