Oil from the BP Deepwater Horizon disaster and the dispersant used to break the oil into tiny droplets might have affected the genetic balance of deepwater corals in the Gulf of Mexico. They also might have altered the thin biofilm that covers and protects the metal of deepwater shipwrecks, according to new research discussed Monday (Feb. 22) at the American Geophysical Union's Ocean Sciences conference in New Orleans.
The scientists were briefed on federal plans to spend $273.3 million restoring deepwater corals and other deepwater organisms damaged by the spill. The coral restoration proposal is part of the final "programmatic" oil spill damage assessment and restoration plan announced by federal and state oil spill trustees last week. The plan will be funded with money that BP has agreed to pay as part of a settlement of outstanding civil claims with federal and state officials.
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Specific projects must wait a year or more to be identified and approved, however, as part of the $20.8 billion settlement, said Brittany Croll, a senior official with the National Oceanic and Atmospheric Administration's damage assessment, remediation and restoration Program. The settlement is awaiting approval of a federal judge in New Orleans.
According to the damage assessment, more than 772 square miles of deepwater habitat for bottom-living organisms surrounding the blown-out BP Macondo well were damaged by the oil spill. The worst effects resulted from oil toxicity to organisms, the smothering of organisms with drilling muds, reductions in the number and types of organisms that live in the bottom sediments and the killing or damaging of the health of deepwater corals.
The damage included significant losses to corals and the fish that live around them along about four miles of coral reefs. But federal agencies also found that the oil potentially exposed 3,280 to 17,375 miles beyond and between the areas known to be damaged, the report said. That area is the feeding habitat for many deepwater fish species, including grouper.
Federal officials expect the restoration projects to include several methods that have not been well tested in restoring corals in deep water, including transplanting coral from healthy areas or by growing new corals and transplanting them into deep water. They might also include placing hard substrate material in locations where corals could begin new colonies or where they would be used by fish that normally live near coral, such as red snapper.
"Restoring these habitats could include placing oyster shell, limestone rubble or a mixture of both substrates to recreate these types of complex habitats, such as low profile reefs or shell mounds, to provide interim habitat as juveniles (fish) move offshore," said an appendix to the report.
The report said such plans might also require restrictions on fishing and oil and gas activities in the project areas to assure they are protected.
The continuing effects of the spill remain a concern, however, as evidenced by new research discussed by Danielle DeLeo, a Temple University researcher. She found that a combination of BP oil and dispersants have changed the genetic code of at least two spill-affected species of coral, Callogorgia delta and Paramuricea type B3.
DeLeo's research has found that the coral are creating more than normal amounts of some genes and not enough of others. The genes in question allow the corals to have the proper immune responses to various diseases or to fight poisons in their environment, to repair wounds and to properly deal with overheating.
And in laboratory tests, she found that the combination of oil and dispersant was much more damaging than just the oil. The BP oil and the dispersants used to break it up might also be speeding up the decomposition of shipwrecks in the gulf, said Jennifer Salerno, a researcher with George Mason University.
Salerno was part of a team of scientists participating in a research program for the Bureau of Ocean Energy Management, which oversees the permitting of oil and gas production in the Gulf of Mexico and also oversees research conducted on shipwrecks in the Gulf.
The team placed platforms containing carbon steel coupons near shipwrecks that were affected by the oil and at wrecks outside the area of contamination for four months, then recovered them and brought them to a laboratory at George Mason University. There, some of the coupons were placed inside experimental "microcosm" tanks and after two weeks to acclimate the metal to the water, tanks were treated with crude oil, dispersant or both, or received no treatment.
The scientists found that the pieces of steel treated with oil and with oil and dispersant had greater corrosion, compared with those that had only dispersant or neither dispersant nor oil. Tests of the microbial organisms in the various treatment tanks also found that the treatments altered the bacterial community structure and of the biofilm of organisms that coat shipwrecks.
A news release announcing the results of the experiment pointed out that a World War II German U-boat U 166 was buried by more sediment than it had been prior to the spill. Researchers are trying to figure out if that's a natural process or the result of the spill.
"These are pieces of our collective human history down there, and they are worth protecting," said Melanie Damour, a marine archaeologist with the Bureau of Ocean Energy Management and co-leader of the project. She said several of the ships might still contain human remains.
"We are concerned that the degradation of these sites a lot faster than normal will cause the permanent loss of information that we can never get back," Damour said.