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May 212010
 

By Barbara Kessler
Green Right Now

The BP oil spill will affect ecosystems in the gulf for a long time and is certain to affect the entire “food web,” wildlife experts said Friday.

A bottle nose dolphin (Photo: NASA)

A bottle nose dolphin (Photo: NASA)

But the government’s team leaders for the rescue and assessment of wildlife could not give  projections for, nor would they hazard guesses about, how bad those effects might be.

“Each oil spill is different, it affects wildlife in varying ways” said  Dr. Ralph Morgenweck, U.S. Fish and Wildlife Service Senior Science Advisor and Liaison Officer at the Unified Area Command. “A lot of these impacts are more subtle than the outside of oil on an animal.”

Morgenweck and others from the Deepwater Horizon Joint Command say the difficulty of assessing this spill begins with its origins as a deep water leak on the sea floor – as opposed to a tanker spill in which oil spreads mainly on the surface waters – to its longevity (a month and counting) and the way it’s been managed with chemical dispersants.

“The reality we have in this situation is, as you know, this very deep spill,” said Dr. Roger Helm, U.S. Fish and Wildlife Service Chief of the Division of Contaminants. But what experts know about oil spills is largely informed by those that spread on the surface from tankers.

The BP spill presents many unknowns, such as how fast the oil is moving up through the water, how much is emulsified when it hits the surface and how effective the dispersants have been, Helm said.

“How do we get our brain around all this?’’ he asked in a morning news conference.

The primary dispersant sprayed on the spill, a detergent-like substance branded as Corexit, has been widely accused of worsening the disaster because it can be toxic to wildlife if ingested. (See a CDC report.)

There remains hope that the dispersants have provided some of their intended benefit, encapsulating the oil so that microorganisms can break it down more quickly beneath the surface. At the same time,  the team of wildlife experts  said they are greatly worried about what’s happening beneath the surface with the dispersants and the oil.

Morganweck conceded that no one knows exactly how the “bazillion little droplets of oil” created by the dispersant action will act.

“We don’t really understand the movement of these droplets,” he said. “This is a giant experiment that’s going on.”

On it’s own, the massive stream of oil floating beneath the line of sight, could devastate marine life as the creatures incur repeated exposures to the oil, Helm said.

“The long term chronic insult” to animals swimming in the oil “has us very concerned,” he said.

“We do anticipate widespread effect to ecosystems,” said Dr. Glenn Plumb, National Park Service Wildlife Veterinarian. Earlier scientific work done on smaller gulf spills shows that, aside from the deaths caused by acute oil poisoning, wildlife populations recovering from a spill that has contaminated their food and environs become less robust and suffer reduced fertility.

Many of the marine life that will be affected, such as sea turtles already are endangered or threatened. The Kemp’s Ridley turtle, listed as endangered since 1970, has been recovering. Manatees, known as the “gentle giants” of the sea, also are endangered. (Jimmy Buffett sponsors as Save the Manatee group.) Manatees, like turtles, graze on underwater vegetation that stands to become clogged with oil, even if surface booms keep the sludge from hitting the sand.

Blue fin tuna, an overfished species already in decline, also are face special risks from the oil spill because they spawn in the gulf.

The spill poses dangers for sharks, another class of marine life in decline, as well. When the balance of life tips against top predators, whole systems can collapse, a topic alluded to but not detailed by the experts speaking Friday.

“We are concerned about the viability of these complex food webs or food chains in the gulf that are so important to the wildlife community there.” Plumb said.

Since the end of April, teams of biologists and government response workers have found:

  • 186 stranded turtles –  Three of those were collected alive at sea swimming near oil, another six were rescued on land and survived. The remaining 17 7 turtles died. Of 70 autopsies completed, none have shown ingested oil. The number of turtle strandings is higher than normal for this period, but it could partly be due to increased human efforts to find them, said Barbara Schroeder, NOAA Fisheries National Sea Turtle Coordinator.
  • 18 dolphins have been found stranded on shore since April 30. None were visibly oiled and one had a complete autopsy that revealed no evident oil, said Dr. Teri Rowles, Director of NOAA Fisheries Marine Mammal Health and Stranding Response Program. Dolphins and whales face acute danger from the oil spill because they must surface to breathe. Those not immediately killed by ingesting oil, could face longterm lethal effects to their immune and organ systems.
  • 43 birds have been found dead and 23 birds affected by the spill have been found alive. Several have been cleaned and released.

Government authorities continue to sample and count wildlife, as best as possible, in areas adjacent to the oil spill to develop a baseline. Crews are at sea looking for dolphin and whales, and closer to shore where bottle-nose dolphin and manatees can be found. Those numbers will be important in assessing the disaster’s toll and quantifying BP’s liability.

While many marine mammals and fish will likely die and never be found, the teams that are mapping the populations also intend to rescue affected or killed animals, Dr. Rowles said.

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