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Post-spill gulf environment appears to have escaped catastrophe, for now

Much of the BP oil spill's effect on the ecosystem won't be known for years, and peril remains, experts warn. Still, the Gulf of Mexico has recovered more quickly than many expected last summer.

April 20, 2011|By Bettina Boxall, Los Angeles Times
  • Tomas Maldonado, center, and Gilberto Reyes, throw nets to catch shrimp off of the quiet docks in Grand Isle, La.
Tomas Maldonado, center, and Gilberto Reyes, throw nets to catch shrimp… (Carolyn Cole / Los Angeles…)

Reporting from Grand Isle, La. — Hundreds of brown pelicans are doing what they always do on Cat Island in the spring: wheeling above the mangroves, nesting and jostling for space on this noisy rookery a few miles off the Louisiana coast.

A year after the Deepwater Horizon oil rig exploded, killing 11 workers and unleashing the largest offshore oil spill in U.S. history, life on Cat seems pretty much back to normal, as it does in most of the Gulf of Mexico environment.

But when Todd Baker takes a close look, he sees that not all is right. Before the spill, "this was a lush green island; you couldn't see the ground," recalled Baker, a biologist with the Louisiana Department of Wildlife and Fisheries. The black mangrove bushes on which pelicans build nests are thin and scraggly, damaged by the oil that sloshed over the two-acre island. A strip of the plants disappeared, wiped out by a loose, wave-driven boom set by spill cleanup crews. It plowed through the dense stand like a bulldozer, destroying nesting perches.

Nests built on the newly exposed sand could be washed away in storms. If the mangroves don't recover, more of the island will erode, imperiling the rookery.

The northern gulf's brown pelican population didn't escape the spill unscathed. But precisely how it was affected, Baker said, "we don't know yet."

The monster spill's toll on the gulf environment is turning out to be more subtle — and at this point, elusive — than was feared when BP's blown-out well spit light crude into mile-deep waters for three long months.

Beaches that were coated last summer with a rusty-colored goo, the product of oil and toxic chemical dispersants, are clean. As of Tuesday, all federal waters had been reopened to fishing. Only a small fraction of ocean and sediment samples taken by the federal government found oil compounds at levels harmful to aquatic life.

Portraits From the Gulf

One year later, five people whose lives were changed by the oil spill share their stories.

"It's been difficult to confirm everybody's worst fears," said Ian MacDonald, an oceanography professor at Florida State University. "My statement all along has been that we probably are not going to see … an acute toxic impact. Instead what we should be concerned about is a marginal reduction in the productivity and biodiversity of the components of the gulf ecosystem…. But that's not something that you know right away."

A small army of government and academic scientists is examining the gulf ecosystem from top to bottom to figure out what the release of 4.1 million barrels of oil and 1.8 million gallons of chemical dispersant did to the environment. They may not have answers for years.

A combination of factors helped the gulf escape ecological catastrophe. The oil was a light crude. Weather, currents and the application of dispersants deep in the ocean kept much of it offshore. The warm-water gulf ecosystem, adapted to abundant natural oil seeps, proved efficient at producing hydrocarbon-consuming microbes that munched their way through the oil and methane.

"Quicker than anyone thought," oil and gas levels in most of the spill area have returned to normal levels, said David Kennedy, an assistant administrator of the National Oceanic and Atmospheric Administration with 30 years of spill experience.

That does not mean, he emphasized, that there is no problem. "The story is not told yet; there's so much still to look at."

Much of the looking is being done as part of the Natural Resource Damage Assessment, a legal process involving federal and state agencies as well as BP and the other companies involved in the Deepwater Horizon drilling operation. Those corporations will pay for the work and will be liable for the costs of environmental restoration.

On Louisiana's Barataria Bay, a federal biologist is using a telephoto lens to photograph the dorsal fins of bottlenose dolphins as they gently breach the olive-brown waters. The fins have unique nicks and notches, which the scientists will use to identify individuals for a population survey. Later in the project, they will obtain tissue samples using a dart fired from a .22-caliber rifle and compare the results with similar data collected last May, before the spill hit the bay.

Shore populations such as the Barataria dolphins tend to stay in their territory, so they were exposed to the oil when slicks spread to the coast. "They're not going to say, 'I don't like it anymore,' and just leave," said Lori Schwacke, a NOAA scientist who is leading the dolphin surveys.

In the years since the 1989 Exxon Valdez oil spill off Alaska, an orca group in Prince William Sound has experienced a steep decline for reasons not fully understood. "It is awfully suggestive that those animals suffered some sub-lethal impacts," said Eric Zolman, a NOAA scientist working with Schwacke. "That's the concern here."

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