The Nature Conservancy logo. Protecting nature. Preserving life.Bill Finch, the director of conservation for The Nature Conservancy in Alabama, is blogging for Cool Green Science about the Gulf of Mexico oil spill and the Conservancy’s efforts to protect the Gulf’s globally significant natural systems. Read all his posts, and see fresh images from the oil spill like the one above in this slideshow from photographer Bridget Besaw.

Everybody’s got a favorite solution to the oil spill that’s spreading through the Gulf of Mexico. 

We can certainly hope that one of them might prove useful.

But because we understand so little about oil, and yet are so eager for solutions, we’re easy targets for snake-oil salesmen.

Consider the microbe cure.

You’ve seen folks on TV and the Internet hawking oil-eating microbes like they were the latest, greatest thing in fighting oil spills.

But before you bet the cleanup on canned bacteria, you should know that the Gulf of Mexico already houses and feeds what must certainly be one of the world’s largest and most diverse populations of oil-eating microbes.

There are oil-eating microbes in the marshes, oil-eating microbes in the water column, oil-eating microbes hovering around natural hydrocarbon vents in the deepest sections of the Gulf.

They’re all different, and they all have their dining preferences, but they’re all the same in the most important way: They greedily feed on the carbon compounds common in plant and petroleum oils.

The good news is, they’re already at work. In a way, this spill will be a rare feast. They’re working as fast as any oil-eating microbes in the world can work to break down and contain this spill.

But here’s the bad news: No matter how many oil-eating microbes you empty into the Gulf of Mexico, their appetites are going to be limited by how much oxygen, nitrogen and other nutrients they can find to aid in their digestion.

It’s likely, for example, that the Gulf is already beginning to suffer because these oil-eating microbes are siphoning off much of the limited oxygen in the water column. That’s one of the sad ironies of this disaster. Many creatures in the Gulf will die not because of the direct toxicity of oil, but because the oil-eating microbes are now in overdrive, sucking up all the oxygen and nitrogen they can find.

In the process of cleaning up the oil, those microbes are likely to create oxygen-deprived dead zones in the Gulf. Those dead zones will not only kill off the fish, they’ll cause the populations of oil-eating bacteria to crash, further slowing the recovery.

The same problem exists on shore. Because there are so many plant oils in marshes, marsh soils are rich in oil-eating bacteria — bacteria that would be just as happy consuming petroleum oils. Unfortunately, many of these bacteria will be suffocated under the thick gooey masses of petroleum that roll ashore. And the bacteria that survive will quickly run out of the nitrogen and other nutrients they need to digest the carbon-rich petroleum oil.

Couldn’t we simply fertilize the oceans to help our native oil-eating microbes get their fill? Not really. Adding nitrogen only magnifies the problem of oxygen loss, and creates a few other problems besides. And mixing sufficient oxygen into the Gulf would require something on the scale of a monumental hurricane.

Finding creatures that can digest oil is easy. Finding creatures that can digest massive, unnaturally large quantities of oil without wrecking the ecosystem in the process may be impossible.

I was recently cornered by an aspiring bioengineer, a sincere scientist, a nice guy. He wanted me to know that he was working hard to develop oil-eating bugs that were “better” than the bugs we already had. I tried not to worry too much — if such a thing were possible, I figured he was at least a few thousand test-tube generations away from creating it.

But let’s suppose he was somehow able to create a bug entirely new, without the normal limitations of the oil-eating bacteria in the Gulf, a superbug that could survive anywhere, chewing through oil regardless of whether there’s enough oxygen, nitrogen and other nutrients to go around.

What happens when these bugs get finished chewing through the petroleum oil in the Gulf of Mexico? If I were such a superbug, I’d start chewing on the marsh soils, with their rich and healthy accumulation of plant carbons and oils, the very oils that gave rise to petroleum in the first place.

And because I was a superbug, and didn’t need as much oxygen and nitrogen as other microbes, I’d eat deeper, eat faster into the marsh than all the plain old bacteria that have been around long enough to know it’s not wise to eat yourself out of house and home.

Here’s the terrible thought we’re all going to have to get used to: There’s no way to simply make this oil disappear.

We can and should stop the flow as quickly as possible, corral it where possible, skim it off the surface as quick as we can. But hundreds of millions of gallons of oil are already so well stirred into the Gulf’s systems and processes, there’s no way to call it back.

It won’t be BP or the Coast Guard or scientists in a laboratory cleaning up the Gulf. The cleanup will be done by the Gulf itself, slowly, violently and at great cost to all the creatures living there.

Our task — the most important human task — will be making sure that there are enough of these creatures and natural systems left to support a full recovery of the Gulf as soon as possible.

— Text by Bill FinchCool Green Science Blog

Related on MNN:

Gulf oil spill: Is there a cure?
Are hay or oil-eating microbes the answer to the Gulf oil spill? The Conservancy's Bill Finch asks if miracle cures are just blinding us to the inevitable.