A laughing gull coated in oil was cleaned in Buras, La. The official
toll of dead birds is about 1,200, but even that is disputed.
It is perhaps the most important question of
the BP oil spill — but scientists
don’t appear close to answering it despite a historically vast effort.
In the 2 1/2 months since the spill
began, the gulf has been examined by an armada of researchers — from
federal agencies, universities, and nonprofit groups. They have brought
back vivid snapshots of a sea under stress: sharks and other deep-water
fish suddenly appearing near shore, oil-soaked marshes turning deathly
brown, clouds of oil swirling in deep water.
But, with key gaps remaining in their
data, there is wide disagreement about the big picture. Some researchers
have concluded that the gulf is being spared an ecological disaster.
Others think ecosystems that were already in trouble before the spill
are now being pushed toward a brink.
“The distribution of the oil, it’s bigger
and uglier than we had hoped,’’ said Roger Helm, a US Fish and Wildlife
Service official and the lead scientist studying the spill for the
Interior Department.
“The
possibility of having significant changes in the food chain, over some
period of time, is very real. The possibility of marshes disappearing . .
. is very real.’’
Helm said
that his prognosis for the spill had worsened in the past week as the
amount of oily shoreline increased from Louisiana to Florida, despite
cleanup efforts. “This just outstrips everybody’s capability’’ to clean
it up, he said.
Yesterday,
Texas officials reported tar balls have washed up on one of the state’s
beaches for the first time.
Yet
research on the entire gulf has mainly occurred in the background, as
public attention has focused on the crisis at BP’s leaking wellhead.
The Gulf of Mexico is a
600,000-square-mile sea which contains swirling currents, sun-baked salt
marshes, and dark, cold canyons patrolled by sperm whales. Complicating
matters is that even before the spill began in late April, this
patient was already sick.
In
recent years, Louisiana has been losing a football field’s worth of its
fertile marshes to erosion every 38 minutes. In the gulf itself,
pollutants coming from the Mississippi River’s vast watershed helped
feed a low-oxygen “dead zone’’ bigger than the entire Chesapeake Bay.
Measuring the spill’s damage, then, requires distinguishing it from the
damage done by these other man-made problems.
So far, even the simplest-sounding
attempts to measure the spill’s impact have turned out to be complex.
The official toll of dead birds is about
1,200, a fraction of the 35,000 discovered after the Exxon Valdez spill in 1989. But this, too, has been
called into question. Officials can count only the birds they can find,
and many think a number of oily birds have sought refuge in the marshes.
“It’s an instinctive response: They’re
hiding from predators while they recover,’’ said Kerry St. Pé, head of a
government program that oversees Louisiana’s Barataria Bay marshes.
“They plan to recover, of course, and they don’t. They just die.’’
Other scientists have focused on more
subjective measures of the gulf’s health — not counting the dead, but
studying the behavior of wildlife, the movements of oil, and the state
of larger ecosystems. For them, solid answers are even more elusive.
For example: Is the oil killing off
Louisiana’s coastal marshes? State officials have said in interviews
that they’ve seen it coating the grasses and mangroves that hold the
region’s land in place.
“The
marsh grasses, the canes, the mangrove are dying. They’re stressed and
dying now,’’ said Robert Barham, secretary of the state’s Department of
Wildlife and Fisheries. “There’s very visible evidence that the
ecosystem is changed.’’
But
Paul Kemp of the National Audubon Society said he flew over the same
area and saw a different picture: The oil’s damage was relatively small,
at least in comparison with the marsh’s existing problems.
“Here, we have a patient that’s dying of
cancer, you know, and now they have a sunburn, too,’’ Kemp said.
“What will kill coastal Louisiana is not
this oil spill,’’ he added. “What will kill coastal Louisiana is what
was killing it before this oil spill,’’ including erosion and
river-control projects that have reduced the buildup of new land.
Further offshore, federal scientists and
university researchers have disagreed about the existence of “plumes’’
of dissolved or submerged oil. Several educators have reported finding
underwater oil dozens of miles from the spill: Sometimes, they reported
it was so well dissolved that the water appeared clear. In other
situations, they found what they thought to be oil globs the size of
golf balls