VOA标准英语2010年-Gushing Oil Threatens Wildlife, Gulf E

The Gulf 1 of Mexico oil disaster comes during spring spawning 2 season, an especially bad time for aquatic 3 life making them extraordinarily 4 vulnerable to the toxic 5 effects of the oil itself, says Doug Rader, chief oceans scientist for the Environmental Defense 6 Fund.

"Now the same thing is happening with birdlife migrating to and from the tropics. Those that have completed their migrations 7 in the Gulf region are nesting and are beginning to feed this year's crop of migratory 8 birds."

As the oil gushes 9 from the broken well head at the sea floor, Rader says it has the potential to contaminate each layer of the water column that, "directly exposes those animals to toxicity 10, at the surface including the very sensitive surface zones where not only sea turtles and marine 11 mammals and sea birds can be oiled, but also where the highways for fish larvae 12 exist. And then as it rains back into the abyss over a much wider area carrying toxicants back into the deep sea where ancient corals and other sensitive ecosystems 13 exist."

Limited choices

One response strategy has been to use dispersants or anti-freeze-like chemicals to break the oil up into smaller globules.

Those particles mix more readily with water, and sink. Rader says dispersants are being sprayed from airplanes and - for the first time - pumped directly into the deep ocean unsure of its effects.

U.S. Navy photo by Mass Communication Specialist First Class Michael B. Watkins

Aerial images of the Deepwater Horizon oil spill taken from a US Coast Guard HC-144 aircraft.

It is a choice, he says, between two bad options. While the chemicals may protect birds and other wildlife by dissipating the slick before it reaches shore, their toxicity in the Gulf could harm fish and other marine life.

Judith Dowell, a biologist with Woods Hole Oceanographic Institution and an expert on oil spill contamination, says it is important to understand the nature of the oil in order to predict its ecological 15 effects.

"If a lot of it is very light material, it is going to vaporize. If a lot of it is heavy material, it may precipitate 16 to the bottom. In the meantime, you have these medium molecular 17 weight compounds that are dispersing 18 within the water column. Until you can get some very accurate measurements of the depth of the slick and the geographical 19 extent of the slick, it's not easy to do."

Widening threat

The slick threatens sensitive coastal 20 wetlands, areas critical to wildlife.

Barrier islands and wetlands also serve to buffer 21 towns on the coast from hurricanes and storm surges. Doug Rader with the Environmental Defense Fund says the spill may finally force coastal communities to put more adequate plans and safeguards in place to prevent an off shore disaster in the future.

Deepwater Horizon Response Center

Workers clean up oil along a beach at South Pass, La. May 11, 2010 near where the Mississippi River meets the Gulf of Mexico.

"There are thousands of wells in the Gulf. There are 35,000 miles [56,000 kilometers] of pipeline 22 in the Gulf," says Rader. "It is pretty clear that the status quo in terms of investment to prevent risk and to respond to events wasn't adequate and that some retrofitting of that entire infrastructure 23 is necessary to be able to sustain the current level of production in the Gulf."

Rethinking offshore 24 drilling?

Rader says the time is also ripe to rethink the wisdom of offshore drilling in favor of other energy options in the face of climate change.

"That going forward with a more balanced portfolio 25 of energy sources that begins to address the global problem of warming caused by greenhouse gas emissions 26 and threatening coastal areas like coastal Louisiana by rising seas and intensifying 27 storms has to be a piece of the mix."

Graphic 14 depicting 28 the Riser Insertion Tube method to contain oil leaking from the riser of the Deepwater Horizon Well.

To this end, on May 12, Senators John Kerry and Joe Lieberman introduced long-awaited climate and energy legislation.

The bill covers a broad cross-section of the nation's top environmental and energy issues, from expanded nuclear power and carbon capture and sequestration, to giving states veto power over drilling within 120 kilometers off shore if, in the language of the proposed law, "they stand to suffer significant adverse 29 impacts in the event of an accident."