BP slows Gulf leak but finds layers of oil underwater | Environment| All topics from climate change to conservation | DW | 18.05.2010
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BP slows Gulf leak but finds layers of oil underwater

Three weeks after the Deepwater Horizon drilling rig sank, some oil has washed ashore in the Gulf of Mexico along with 150 dead sea turtles. Experts say layers of oil stretching for miles have formed underwater.

Protective booms surround an island near the mouth of the Mississippi River

The spill is prompting desperate measures to contain the environmental fallout

After initially bracing for a glut of oil leaking from a British Petroleum well in the Gulf of Mexico to wash ashore in Louisiana, experts have now warned large amounts of oil have pooled below the waters' surface.

One layer of oil is reportedly 15 to 20 miles long and four or five miles wide. Microbes will break down some of it, but in doing so will deplete oxygen levels in the water, possibly making it uninhabitable for marine life.

British Petroleum has said it is premature to blame the layers of oil below the surface on the use of an untested technique of injecting chemical dispersants into the underwater source of the oil leak.

Workers clean a bird covered in oil

Some birds have been affected by the oil spill

Some success in slowing leak

After an attempt failed to place a dome-like structure over the well to trap leaking oil and pipe it to a waiting ship, British Petroleum has had some success in staunching the flow of oil by inserting a mile-long tube into the well. The tube redirects some of the flowing oil to a ship on the surface, but massive amounts continue to leak.

The drilling of a relief well started on May 2 and is expected to take up to 90 days. Once it is complete, the leaking well can finally be capped.

Certain loss of wildlife

Michael Stachowitsch, a researcher at the Department of Marine Biology at the University of Vienna, said the Gulf of Mexico is home to a "mosaic of different ecosystems," which will be affected regardless of how the spill is handled.

An aerial view of part of the oil spill in the Gulf of Mexico

One layer of oil is reported to be 15 to 20 miles long and four or five miles wide

"It'll be a disruption of normal ecosystem processes," he told Deutsche Welle. "You'll have the removal of certain components of the ecosystems… certain animals will be reduced, maybe even a generation of certain populations of fish might be lost."

Stachowitsch says oil will stay in the environment for a long time regardless of the type of cleanup technique deployed. Dispersant chemicals can break a glut of oil into smaller portions, which may sink, but they are also toxic. If oil sinks, it "obviously smothers and kills anything on the sea bottom."

"Breaking oil down to smaller parts makes it easier for bacteria to break it down, but it also makes it easier for these particles to be taken up into the food chain," he said.

If oil pools on the water's surface, however, it affects birds and organisms which come to the surface to breathe such as whales, dolphins and sea turtles.

'Dead zone'

The Gulf of Mexico is also seasonally affected by the largest of the world's 400 'dead zones,' which are areas of water where depleted oxygen levels have made it impossible for higher forms of life to survive on the bottom of the sea.

The 'dead zone' in the Gulf of Mexico forms each spring when agricultural runoff washed out to sea by the Mississippi River spurs the growth of algae, which drains the oxygen from coastal waters. The waters are also polluted by other elements such as heavy metals, plastics and pesticides.

There is a "multitude" of simultaneous threats to ecosystems in the Gulf of Mexico and elsewhere. "One shouldn't forget that all the others are going on in parallel," Stachowitsch said.

Once oil has leaked, options for protecting wildlife are limited. "There's almost nothing you can do. They try to avoid it getting on the beach, and they fight it as well as they can while it's on the water. Once it's on the beach it's a different ball game. You give (volunteers) a shovel, and you give them a bucket, and you give them some boots."

A satellite image of the oil spill in the Gulf of Mexico

Satellite images show the oil spreading in the Gulf of Mexico

Loop Current feared

Fear that the Loop Current in the Gulf of Mexico could carry oil to Florida and spoil the coral of the Florida Keys and Miami Beach has intensified after satellite images showed one of the current's two eddies pulling oil towards the state.

In recent weeks at least 150 dead sea turtles have washed ashore, more than usual for the current time of year, along with 12 dead dolphins. So far oil been not definitively been established as the cause of any animal's death, though.

Emergency operations in Louisiana, Mississippi, Alabama and Florida have increased dramatically in scope over recent weeks. On April 30 about 2,000 people and 75 vessels were engaged in clean up operations. Those figures have jumped dramatically with about 17,000 people and 750 vessels now helping contain the problem. The disaster started after a drilling rig leased by BP exploded and sank last month, killing 11 crew members.

Author: Gerhard Schneibel
Editor: Nathan Witkop

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