Oil spill

Emergency workers in the US state of Louisiana braced for a glut of toxic crude oil to wash into the state's sensitive coastal wetlands after the "Deepwater Horizon" drilling rig exploded on April 20 and sank into the Gulf of Mexico two days later.

But as of Thursday morning, the scenario has yet to manifest itself, though the well dug by the British Petroleum-leased rig is still gushing oil at a depth of 5,000 feet some 80 kilometers (50 miles) offshore.

Using remote-controlled submarines, BP has closed the smallest of three leaks in the broken pipe which connected the wellhead with the Deepwater Horizon. While oil is expected to continue escaping at an unchanged rate, efforts can now be concentrated on the two remaining leaks.

Estimates indicate more than 9 million liters (2.5 million gallons) of oil have leaked from the well since April 22. The estimated 5,000 barrels leaking each day represent 1 to 2 percent of the 1989 Exxon Valdez spill, according to Simon Boxall, an oceanographer at the National Oceanography Centre in Southampton, Britain.

"The problem, of course, is it's an ongoing spill, and if it's left unchecked, it will become a major disaster. So it's important it's plugged as quickly as possible," he told Deutsche Welle.

'Dome' to be used

In what is being described as an unprecedented technique, a barge laden with a 100-ton dome made of concrete and steel arrived Thursday at the disaster site. The dome or containment chamber will be lowered over the most significant leak, hopefully trapping escaping oil by Monday and allowing it to be piped into an oil tanker.

A London-based BP spokesman told Deutsche Welle: "Once we've got this thing on the seabed, it will contain the source of about 85 percent of the oil that is currently leaking. There is not a lot of complicated technology involved, but this is untried at these depths."

BP is also drilling a relief well near the disaster site, which is expected to take two to three months to complete. It will take pressure off the leaking well, allowing it to be capped.

No oil onshore yet

Forces of nature have not worsened the situation so far, as luck would have it. In addition to 2,000 emergency responders, 11,000 people have volunteered to help along coastlines, 4,000 of whom have already been trained, the spokesman said. "The wind and the weather have been kind to responders so far."

Unofficial reports of oil near the Chandeleur Islands of Louisiana led to a flurry of activity in which shrimp trawlers and response boats began laying protective barriers called booms.

"This is the way we're dealing with it – as soon as there are any reports of it being near shore, we're sending lots of people lots of equipment to fight it as aggressively as we can," the spokesman said.

The islands house the Breton National Wildlife Refuge, where some 1,200 brown pelicans are currently nesting for the season.

According to the San Francisco-based International Bird Rescue Research Center, egrets and terns also nest and feed in the affected areas. Tides, weather and other factors beyond the emergency workers' control influence the environmental impact of the disaster.

Jay Holcomb, the center's director, said cleaning a bird covered up to 80 percent in oil requires three emergency workers, water, soap and a lot of patience. Even once a bird has been cleaned, though, it's not sure it will survive.

"If (birds) eat a lot of oil, they can experience an anaemia. They could also have kidney and liver damage, things like that" he said.

Fishing industry damaged

Although the most intensive emergency response efforts have been taking place in Louisiana, the adjoining coastal states Alabama and Florida have also declared states of emergency. Fishery industries throughout the region have been closed down, resulting in widespread economic devastation.

Fisherman Mark Cahill is pessimistic about the effects the oil spill will have on fish populations in the Gulf of Mexico.

"The spawn this year is probably shocked. There is not going to be any fish coming back next year. So you got a whole year class of fish that is going to be gone, and who knows about the year after that," he said.

Another fear recently publicized is that beaches and coral reefs in the Florida Keys could be affected should the Loop Current of the Gulf Stream push further north than usual before heading east. Florida's Dry Tortugas islands are home to some of the largest and most preserved coral beds in the world.

Diego Lirman, a coral expert at the University of Miami's Rosenstiel School of Marine and Atmospheric Science, told AFP the sensitive marine organisms could be severely damaged by exposure to "the oil itself, as well as to the chemical dispersants being used to contain the spread of the spill."

Chemical dispersants used

Chemical dispersants, while controversial, have been somewhat successful in dealing with the leaking oil. In another untested technique, emergency workers have been pumping dispersant directly to the source of the leak instead of only applying it to the water's surface from airplanes and boats. Additional chemical dispersant is being brought to the site from Britain and Saudi Arabia.

"So far it seems to be effective. The Coast Guard, which is in charge, is allowing us to continue that, which is good news," BP's spokesman said. "The way they measure whether it's a success or not is by aerial over-flights, and they can use … imaging techniques to measure the scale: how much oil is reaching the surface, and how thick it is."

A controlled burn of oil on the water's surface is being done in an attempt to reduce the volume of the slick at its thickest points.

Author: Gerhard Schneibel /DW/AFP
Editor: Anke Rasper