April 18, 2011

One Year Later: Assessing Impact of Deepwater Horizon

Carl Safina, at Yale Environment360, summarizes the damage, much less than had been feared:
It’s been a year since the blowout in the Gulf of Mexico — so a little hindsight is now in order. Recklessness caused the worst unintended release of oil ever; lives were lost and permanently changed. By definition, we won’t know the long-term consequences until the long term. Scientific studies are ongoing. Some government findings are being held as potential evidence in court cases, distorting the usual scientific atmosphere that seeks understanding through openness. Frustratingly, as of now, many questions remain.

And there may be some surprises. Most people feared major die-offs of fishes and shrimp in the northern Gulf. But when areas closed because of oil were reopened to fishing, fishing was generally excellent. A season closed to fishing may have done more to help the fish than the oil did to hurt them. 
While the oil was flowing, fewer dolphins died than many had feared; it seemed they perhaps dodged the brunt of the oil. But in March and April of this year, newborn dolphins were washing up dead in high numbers in the northern Gulf — a very unpleasant surprise, but not unprecedented. Did the oil kill them? An unrelated infectious disease? Were they more susceptible to disease because of the oil? No one knows.

The Gulf is the only nesting area for Kemp’s Ridley turtles — the world’s most endangered sea turtle. Many turtles that washed up, including Kemp’s Ridleys, showed no visible signs of oil. Did fishing nets kill them? And of those that did die in oil, how many went undetected? 
In other oil spills, a rough rule of thumb is that for every carcass found, nearly ten times that number go undetected. According to the New York Times, researchers are now dropping bird carcasses offshore to see how many will sink and how many will wash ashore, which may help them determine how many birds were killed by oil beyond those that were found.

And while most people did not get sick, a disturbing number of individuals — perhaps more sensitive or more exposed — continue to complain of significant health problems since the blowout and the spill. 
The deep plumes have already dissipated, apparently eaten by the Gulf’s oil-adapted microbes. Yet some of that deep oil seems lodged in seafloor sediments, and, up to seven miles from the wellhead, it appears to have killed some deep-sea coral.

But was it, as was often said, “the worst environmental catastrophe in American history”? Well, no. Many people feared the blowout would kill the great marshes of the Mississippi Delta. Some even feared it would kill off the whole ocean, or worse. But while the blowout wasn’t the ongoing ecological catastrophe that some predicted, there exist much bigger long-term problems we don’t fear nearly enough. . . .

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