Sunday, May 16, 2010

More is known about the surface of the moon than about the world at the bottom of the sea

It is impossible to know the full impacts that the tragic oil leak in the Gulf is and will ultimately have on the region's ecosystems and economies. That's in part because we still don't know (or aren't being told) the rate at which oil is spewing from the leak nor are we close to fully understanding the complex ecosystems that reside in the ocean depths.

One thing the BP executives probably have figured out as they shamelessly attempt to convince Congress to cap how much they will be responsible to pay for damages is that there's no amount of money that can repair the damages resulting from this catastrophe. (GW)

Oil spill imperils an unseen world at the bottom of the gulf

By Joel Achenbach
Washington Post
May 16. 2010

In total darkness at the bottom of the Gulf of Mexico lives a creature with many scuttling legs and two wiggling antennae that jut from a pinched, space-alien face. It is the isopod, Bathynomus giganteus, a scavenger of dead and rotten flesh on the mud floor of the gulf.

"If you think of a giant roach, put it on steroids," said Thomas Shirley, a marine biologist at Texas A&M University. "They can be scary big."

There is beauty in the lightless deep as well. Fan corals, lacylike doilies, form gardens on the seafloor and on sunken ships. The deep is full of crabs, sponges, sea anemones. Sharks hunt in the dark depths, as do sperm whales that feed on giant squid. The sperm whales have formed a year-round colony near the mouth of the Mississippi River, and have been known to rub themselves on oil pipes just like grizzlies rubbing against pine trees.

This is the unseen world imperiled by the uncapped oil well a mile below the surface of the gulf. The millions of gallons of crude, and the introduction of chemicals to disperse it, have thrown this underwater ecosystem into chaos, and scientists have no answer to the question of how this unintended and uncontrolled experiment in marine biology and chemistry will ultimately play out.

The leaking gulf well, drilled by the now-sunken rig Deepwater Horizon, has cast a light on a part of the planet usually out of sight, out of mind, below the horizon, and beyond our ken. The well is surrounded by a complex ecosystem that only in recent years has been explored by scientists. Between the uncapped well and the surface is a mile of water that riots with life, and now contains a vast cloud of oil, gas and chemical dispersants and long, dense columns of clotted crude.

"Everybody fixates on the picture of the cormorant or the bird flailing around all covered with oil, and while that's obviously sad to see, no one should assume there's not similar things occurring in the open ocean," said Andy Bowen, an oceanographer at Woods Hole Oceanographic Institution in Massachusetts. "It's not like the open ocean is irrelevant."

More is known about the surface of the moon than about the world at the bottom of the sea. Scientists long ago clung to the "azoic hypothesis" about the deep -- the presumption that nothing could possibly be alive so far from the photosynthetic world.

Gradually that belief succumbed to living proof to the contrary. Life finds a way. Instead of photosynthesis, there is chemosynthesis. Organic matter rains into the depths from higher in the water column. Oil itself is a part of this mysterious universe, leaking naturally from the seafloor. It is testament to life's ingenuity that for some bacteria, oil is food.

The broken well is 5,000 feet below the surface, on the continental slope, which is the long hill that runs from the edge of the continental shelf to the abyssal plain in the central gulf. The pressure is about 2,230 pounds per square inch, 152 times that of the atmosphere at sea level. The temperature is just a few degrees above freezing.

But the Deepwater Horizon well is in an area that is comparatively well explored. Scientists have been actively studying the deep coral reefs of the gulf, in many cases venturing personally in submersible vessels that can withstand the crushing depths. This strange realm can be disorienting.

"It's sort of like being in the Grand Canyon with the lights out and in a snowstorm," Bowen said.

The topography is full of knolls, hills, canyons -- the leaking well is located in Mississippi Canyon Block 252 -- and the sea bottom is not simply mud.

"You can go one place and it would be like quicksand. You can move over another ways, and it would be as hard as a sidewalk," said Rich Camilli, an oceanographer at Woods Hole who in 2006 made a series of dives to the gulf floor eight miles northwest of the blown-out well. His journey about 3,000 feet below the surface took place right after an earthquake.

"It looked like all hell had broken loose on the seafloor," Camilli said.

Embedded in the mud are structures made of methane hydrates, the slushy ice that forms when pressurized gas mixes with very cold water at depth. These are the hydrates that accumulated inside a huge steel containment dome that had been lowered over the major leak from a collapsed pipe. Because of the hydrates, BP engineers had to abandon that strategy for capturing the leaking oil.

When Camilli observed hydrates after the earthquake, they "had broken away from the seafloor and had floated up and away. They're buoyant. One site, called Sleeping Dragon, a massive hydrate block was working its way out of the seafloor -- about the size of a school bus. There were pockmarks where the hydrates come out of the sea floor."

This region of the gulf is fertilized by organic matter from the Mississippi River. It is rich in plankton and other organisms. The result is what is called marine snow, which is easily seen in the brief snippets of video released by BP that show the leaking pipe.

"There's this particulate matter that's falling like rain, or like snow, through the ocean, all the way from the surface to the bottom," said Peter Etnoyer, a marine biologist with the National Oceanic and Atmospheric Administration. "There's thousands of creatures in the water column. As you descend though the water column, you'll see many bioluminescent plankton."

The depths of the gulf are also a potential answer to a question that has been in the air for weeks now: Where, exactly, has all the oil gone? A partial explanation is that the slick has been bombed with more than half a million gallons of the chemical dispersant Corexit 9500, made by Nalco. More dispersants have been applied at depth, directly on the main leak. Much of the oil sinks to the bottom.

"If you apply the dispersants to the source of the oil down there, you are completely hiding the problem," said Kert Davies, research director for Greenpeace. "It looks like it's gone away, but there is no 'away' in the ocean. It's like sweeping it under the rug."

Shirley, the marine biologist, notes that oil is not a foreign substance in the gulf: "What most people haven't considered is that there's 48 million gallons of oil that's leaked naturally in the gulf every year."

Ian MacDonald, the Florida State University professor who has gained attention with his estimate, based on aerial images, that the leak is five times the official estimate of 5,000 barrels a day, said nature will ultimately have to fix the gulf mess. "BP is not going to clean up this spill," he said. "The Coast Guard is not going to clean up this spill. What's going to clean up this spill is the physical, chemical, biological process of the good ol', poor, downtrodden Gulf of Mexico."

Life is an active and improvisational agent in the deep water. Corals have found purchase on dozens of ships sunk in the gulf in 1942 when Nazi U-boats patrolled the shipping lanes. Scientists study the doomed vessels to get a better idea of coral growth rates at depth.

Less than a mile from the uncapped well, now upside down, is the hulk of the Deepwater Horizon rig. It is now, in effect, an artificial reef, destined to become another garden of the deep.


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