It's been three weeks since an oil rig exploded off the Louisiana coast, spewing oil into the Gulf of Mexico. As workers try to keep the oil from reaching -- and damaging -- the shoreline, ecologists warn that a cleanup effort in the wetlands could be more harmful to the ecosystem than the oil itself.
Chris Craft, a wetlands expert in Indiana University's School of Public and Environmental Affairs and past president of the Society of Wetland Scientists, said plants are particularly vulnerable. "I'm not advocating not doing anything," he said, "but I'm saying we need to be careful that the cleanup doesn't compound the problem."
Craft called me last week from Sapelo Island, off the Georgia coast, where he's doing field work in the tidal marshes.
How could the oil cleanup be worse than the spill in terms of ecosystem damage?
In Louisiana, the areas that they're most concerned about are these vegetative wetlands at the mouth of the Mississippi River. [In the] cleanup of oil, some of the techniques they use are pretty harsh, like high-pressure washing. On rocks or sandy shores, it's still pretty harsh. But imagine trying to use some of these techniques on vegetative marshes. The plants just cannot handle it. [Also] a lot of people will be out on the marsh sopping up oil. People end up trampling the vegetation. I'm not saying they shouldn't try to clean it up. But [with] some of the techniques they use, they almost sterilize the soil and kill the vegetation in the process of removing the oil.
Other than pressure washing and foot traffic, which aspects of the cleanup are the most problematic?
One thing I've been hearing about with this current spill is the idea of using some of these chemical dispersants in the water. Not on the marsh, but actually trying to disperse the oil out where it's leaking. This for me is second-hand knowledge, but what I understand of the dispersants, they don't really know a lot about the effects on the animals. The key is to keep the oil off the marsh, to do what they can to keep it from coming ashore by using booms to try to intercept it and to skim [off] that oil on the surface. Prevention is probably the best solution in this case.
Are there alternative cleanup methods that we should use?
I'm not sure if there are alternatives to some of these chemical and technology methods. Marshes are pretty resilient, but they are susceptible to human disturbance. The vegetation will end up not being as adversely affected by the oil as the animals will. But you can still put enough oil on the marsh where it will kill the plants. I can't really think of any natural solutions other than really just trying to intercept it before it starts washing up into these areas.
What long-term damage to you expect the ecosystem will sustain from the cleanup?
Some of these drastic techniques to try to disperse the oil and break it up, you just can't apply that to a vegetative surface. You'll just blast plants and kill them. The public is clamoring for BP to do something, but some of us are just saying, "Be careful what's done on the marsh because sometimes the remedy may be as bad as the oil itself." Of course, it depends on how much comes ashore, too.
Didn't we learn anything from previous spills, such as Exxon Valdez and Amoco Cadiz, about how best to clean up?
[In those spills] the oil washed ashore on sandy beaches and on rocky shorelines. It's easier to remove oil from those types of habitats than it is to remove it from a densely vegetative marsh like you have on the coast of Louisiana. I think the challenges in Louisiana and the Gulf are greater with the potential magnitude of the spill and the sensitive nature of marsh vegetation relative to non-vegetative shorelines. These vegetative marshes are definitely a lot more fragile, so the techniques that have been used in the past are not going to be as effective. And they have the potential to be more harmful. They need to think about whether the techniques they used in the past are appropriate.
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Image: Chris Craft (center) with students
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