VENICE, La. – Biologist Dennis Takahashi-Kelso peered into the cobalt waters of the Gulf of Mexico 20 miles off the Louisiana coast. The only sign of pollution was a plastic bag floating beneath the surface.
More than three weeks after the Deepwater Horizon rig exploded and damaged well equipment started spewing 210,000 gallons of crude per day into the Gulf, the fouled beaches and dead seabirds that are the hallmarks of catastrophic spills have yet to materialize.
But Takahashi-Kelso, who was Alaska’s commissioner of environmental conservation at the time of the Exxon Valdez disaster, warned: “It’s going to be bad.”
Even as the spill breaks into separate strands, a nasty environmental storm is brewing below the surface, in deep columns of water teeming with life, from shrimp and fish eggs to dolphins and whales.
Experts don’t know what the oil is doing to the complex web of offshore life. Most of their experience is with shallow-water spills that bleed black goo onto beaches that are cleaned up relatively quickly.
The BP well blowout, 48 miles off the Louisiana coast, is different. Oil is gushing from a tangled, broken pipe lying on the seafloor nearly a mile beneath the surface. The leak will be a month old this week, and if it is not stanched by then, it will have spilled about 6.3 million gallons.
“We have no idea where the oil that isn’t reaching the surface is going,” said James Cowan Jr., an oceanography professor at Louisiana State University. “It could go everywhere.”
The rust-tinted light crude sloshes around a part of the Gulf that is a major pathway for marine life, where the nutrient-filled waters of the Mississippi River mix with the ocean.
“It’s a significant ecosystem that goes from the bottom to the top waters,” said Roger Zimmerman, a marine biologist who directs the Galveston Laboratory, part of the National Oceanic and Atmospheric Administration’s Fisheries Service. “This is a rich area in terms of biological productivity and diversity of animals. There’s a lot of reproduction.”
Red snapper, red drum, Gulf menhaden and other fish use offshore waters east and west of the Mississippi Delta as nursery and spawning areas.
A big part of the country’s commercial shrimp catch comes from the waters on either side of the undersea Mississippi Canyon, the site of the BP blowout. The canyon, which cuts through the continental shelf, harbors deep sea coral.
Pelicans and other seabirds that dive into the slick to catch prey will bathe in the oil and carry it back to their nests, where eggs can absorb it, possibly killing the chick developing inside. Sea turtles and dolphins, which surface twice a minute to breathe, will inhale harmful fumes as they swim through the slick.
“This is such sticky oil in its emulsified and dispersed form that there are mechanisms of harm that we don’t usually look at,” said Charles Peterson, a professor of marine sciences at the University of North Carolina who studied the effects of the 1989 Exxon Valdez spill on Alaska’s Prince William Sound.
What happens on the surface also affects the deep-sea creatures living far below, where they are nourished by the rain of plankton particles from above. “If that productivity is eliminated or if it’s contaminated, all of that will go to the seafloor,” said Gilbert Rowe, a professor of oceanography and marine biology at Texas A&M.
The light nature of the crude spouting from the leak is good and bad. Rather than the thick, viscous pancake of oil that Takahashi-Kelso remembers floating on the ocean in the Exxon Valdez spill, the BP oil is rising to the surface as a mousse.
That means it could decompose more quickly. But it also floats through the water in snow-like bits that increase exposure to the oil’s toxins. “That’s all suspended in the water column where the organisms are found,” Peterson said.
The widespread spraying of chemical dispersants on the surface slick may be compounding exposure and speeding oil uptake into the food chain, scientists warned.
The problem, said George Crozier, executive director of the Dauphin Island Sea Lab, is that it is easier for particle-munching microorganisms to ingest the broken-up bits of oil. “They’re not very discerning about what they’re eating. They were less likely to chew on a big glob than if it was broken down to a particle size.”
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