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Associated Press Report: Oil spill culprit for heavy toll on coral
By CAIN BURDEAU, Associated Press – 52 minutes ago
NEW ORLEANS (AP) – After months of laboratory work, scientists say they can definitively finger oil from BP’s blown-out well as the culprit for the slow death of a once brightly colored deep-sea coral community in the Gulf of Mexico that is now brown and dull.
In a study published Monday, scientists say meticulous chemical analysis of samples taken in late 2010 proves that oil from BP PLC’s out-of-control Macondo well devastated corals living about 7 miles southwest of the well. The coral community is located over an area roughly the size of half a football field nearly a mile below the Gulf’s surface.
The damaged corals were discovered in October 2010 by academic and government scientists, but it’s taken until now for them to declare a definite link to the oil spill.
Most of the Gulf’s bottom is muddy, but coral colonies that pop up every once in a while are vital oases for marine life in the chilly ocean depths. The injured and dying coral today has bare skeleton, loose tissue and is covered in heavy mucous and brown fluffy material, the paper said.
“It was like a graveyard of corals,” said Erik Cordes, a biologist at Temple University who went down to the site in the Alvin research submarine.
So far, this has been the only deep-sea coral site found to be seriously damaged by the spill.
On April 20, 2010, the well blew out about 50 miles off the Louisiana coast, leading to the death of 11 workers aboard the Deepwater Horizon drilling rig and the nation’s largest offshore spill. More than 200 million gallons of oil were released.
“They figured (the coral damage) was the result of the spill, now we can say definitely it was connected to the spill,” said Helen White, a chemical oceanographer with Haverford College and the lead researcher.
She said pinpointing the BP well as the source of the contamination required sampling sediment on the sea floor and figuring out what was oil from natural seeps in the Gulf and what was from the Macondo well. Finally, the researchers matched the oil found on the corals with oil that came out of the BP well.
Also, the researchers concluded that the damage was caused by the spill because an underwater plume of oil was tracked passing by the site in June 2010. The paper also noted that a decade of deep-sea coral research in the Gulf had not found coral dying in this manner. The coral was documented for the first time when researchers went looking for oil damage in 2010.
The findings were published in the Proceedings of the National Academy of Sciences.
The scientists said that they have gone back to the dying corals by submarine since 2010, but that they are not ready to talk about what they’ve seen at the site.
However, Charles Fisher, a biologist with Penn State University who’s led the coral expeditions, said recovery of the damaged site would be slow.
“Things happen very slowly in the deep sea; the temperatures are low, currents are low, those animals live hundreds of years and they die slowly,” he said. “It will take a while to know the final outcome of this exposure.”
BP did not immediately comment on the study.
The researchers said the troubled spot consists of 54 coral colonies. The researchers were able to fully photograph and assess 43 of those colonies, and of those, 86 percent were damaged. They said 10 coral colonies showed signs of severe stress on 90 percent of the coral.
White, the lead researcher, said that this coral site was the only one found southwest of the Macondo well so far, but that others may exist. The researchers also wrote in the paper that it was too early to rule out serious damage at other coral sites that may have seemed healthy during previous examinations after the April 2010 spill.
Jerald Ault, a fish and coral reef specialist at the University of Miami who was not part of the study, said the findings were cause for concern because deep-sea corals are important habitat. He said there are many links between animals that live at the surface, such as tarpon and menhaden, and life at the bottom of the Gulf. Ecosystem problems can play out over many years, he said.
“It’s kind of a tangled web of impact,” he said.
Copyright © 2012 The Associated Press. All rights reserved.
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http://news.sciencemag.org/sciencenow/2012/03/frothy-gunk-from-deepwater-horiz.html?ref=em
Science: ‘Frothy Gunk’ From Deepwater Horizon Spill Harming Corals
by Sid Perkins on 26 March 2012, 3:00 PM |
Blowout! Oil spilled from the Deepwater Horizon (inset; satellite image shows extent of spill on 24 May 2010) injured deep-water corals at one spot about 11 kilometers from the well, new research reveals.
Credit: NASA/GSFC/MODIS Rapid Response, demis.nl and FT2; (inset) U.S. Coast Guard
The massive oil spill that inundated the Gulf of Mexico in the spring and summer of 2010 severely damaged deep-sea corals more than 11 kilometers from the well site, a sea-floor survey conducted within weeks of the spill reveals. Although 10 more distant sites examined during the survey did not show any ill effects, future studies will be needed to confirm that they did not suffer long-term detriment from any exposure to oil, scientists say.
Starting with an explosion onboard the Deepwater Horizon oil drilling rig on 20 April and continuing for 85 days, the worst oil spill in U.S. history released an estimated 4.9 million barrels of oil — about 20 times the amount spilled by the Exxon Valdez in Alaska in 1989.
Between 3 and 4 months after the well was capped, researchers used the deep submersible vehicle Alvin and the remotely-operated vehicle Jason II to revisit several sites along the continental shelf known to host corals, says Charles Fisher, a team member and deep-sea biologist at Pennsylvania State University, University Park.
The researchers also used previously collected sonar data to identify a possibly rocky patch of sea floor where corals could thrive about 11 kilometers southwest of the well site.
At that 1370-meter-deep site, which hadn’t been visited before but had been right in the path of a submerged 100-meter-thick oil plume from the spill, the researchers found a variety of corals-most of them belonging to a type of colonial coral commonly known as sea fans-on a 10-meter-by-12-meter outcrop of rock. Nearby, boulders poking up through the sediment hosted isolated colonies of coral. Many of the corals were partially or completely covered with a brown, fluffy substance that Fisher variously calls “frothy gunk,” “goop,” and “snot.”
Samples of the material contained mucus secreted by the corals-a sign the colonies had recently been under stress-as well as fragments of dead coral polyps, saturated and unsaturated fatty acids commonly found in biological tissues such as cell membranes, and a mélange of petroleum residues. Although the chemicals related to petroleum-including long-chain hydrocarbons, polycyclic aromatic hydrocarbons, and a group of compounds known as hopanoids-could have originated from other oil wells or natural sea floor seeps in the area, measurements of the ratios of specific hopanoids identify the Deepwater Horizon spill as the source of the oil, the researchers report online today in the Proceedings of the National Academy of Sciences. “It’s like a fingerprint,” says Helen White, a geochemist at Haverford College in Pennsylvania and a co-author of the new research.
In almost half of the 43 corals studied at the site, the majority of animals had died or were showing signs of stress, the researchers say. And in more than one-quarter of the corals, more than 90% of the animals showed such damage. Also, more than half of the brittle stars, a relative of starfish, found clinging to the sea fans were partially or completely bleached white, another certain sign of stress, says Fisher.
The new findings “show clearly the very negative effects in deep-water communities from this spill,” says Samantha Joye, a biogeochemist at the University of Georgia in Athens who wasn’t involved in the research. The true extent of damage from the spill is, for now, tough to determine because so much of the sea floor hasn’t been examined, she notes. “The deeper you look, the more you’re going to find.”
Also, Joye notes, areas that weren’t immediately damaged by oil plumes in the wake of the spill may be later exposed to oily material lofted from the ocean floor by strong currents or by human activities such as trawling. “This stuff is like the foam on a latte,” she says. “It’s very fluffy.”
Special thanks to Richard Charter