Tim Chitwood

Deep-water trouble on the Gulf horizon

A University of Georgia biogeochemist who’s been studying the Gulf of Mexico since 1994 came to Columbus last week to say what scientists know about the long-term effect of the catastrophic BP oil spill.

What do they know? Not that much, said Samantha Joye of the university’s marine sciences department.

That’s partly because the massive deepwater oil spill is unprecedented, and partly because the gulf’s ecosystem hasn’t been monitored extensively over the years. So researchers don’t have the background data by which to gauge the spill’s impact, Joye told the Columbus Rotary Club Wednesday.

BP’s Deepwater Horizon rig exploded April 20. It since has injected about 4 million barrels of oil in to the gulf, at 42 gallons per barrel. That’s 10 to 30 times the amount that seeps naturally into the ecosystem through fault lines, and it has left plumes of oil 3,000 to 3,900 feet down. One plume was 4 miles wide, 25 miles long and 900 feet thick.

Because the gulf has so many natural oil seeps — at least 1,000 on its shelf and slope release 1,000 to 2,000 barrels a day — ecosystems have developed to deal with it. Microbes feed on the oil and break it down, and that’s good.

But those microbes also consume oxygen, and that’s bad, because if a legion of microbes comes swarming to eat the oil and starts sucking up all the oxygen deep in the ocean where it cannot rapidly be replaced, that may create dead zones from which larger life forms like fish and squid will be excluded. The damage could last years or decades.

That’s in addition to all the other damage the oil is doing, such as killing off blue crab larvae and coating waterfowl.

Then there’s the other chemical infusion underway: The millions of gallons of dispersant being used to break up the oil. No one seems to be tracking how much of that’s going into the gulf, but for it to work, the amount of dispersant to oil has to be 10 to one, Joye said. The stuff is 10 times more toxic than oil, and no one knows what its long-term impact will be, either, she said.

What researchers do know is that the dispersant chemicals become “bio-concentrated,” so they get into the food chain and work their way up, Joye said. Meanwhile, the dispersed oil breaks up and sinks to the bottom, where it stays. Nothing down there’s going to mop it up.So the big BP blowout isn’t just a big mess for the moment. It’s a big mess for the future, too, and unless a lot more research gets done pretty quickly, no one’s going to be able to gauge exactly how big a mess, said Joye, 44, who completed one cruise through the gulf May 25-June 5 and hopes to return in mid-August.

To the U.S. House Committee on Science and Technology, she on June 9 urged an extensive, organized study. Else we won’t know the full impact of the oil spill for years.

And then it might be more than we can handle, if it’s not already.