Archive for November, 2010

Where’s the oil?

Six months ago, there was a massive oil spill in the Gulf of Mexico, and besides the soiling of coastal waters, there was a concern that such a great quantity of oil could be swept into the Gulf Stream and be carried as far as Europe. This did not happen, and then the question was: where did the oil go? Did it sink? Odd thing for oil to do on water, right. Sinking is what water generally does in oil. And this is salt water, so it’s even heavier.

But where is it, then?

Well, oddly enough, oil is enough like butter that, though we can’t eat it, other creatures can, and over the millenia that the oceans of the world have dealt with seepage of oil in various places, creatures who love this stuff have found their place in the waters of the world. I first heard of this in connection with one of the Pacific oil spills, and that’s a long way from the Gulf, but on the other hand, the oceans of the world fully circulate at least every 2-3 years. They are not sequestered from each other. Bacteria that eat oil are definitely out there, probably more or less everywhere.

So, how would you know if the oil had been eaten? (Other than it’s not there, of course.)

You would know because there are two stable isotopes of carbon, carbon 12 and carbon 13. Both atoms are able to participate in all reactions that involve carbon, and both stick around; neither is radioactive. But actually, some plants prefer the carbon 12, just because it’s lighter, and, to make a long story short, these ancient oils tend to be short of carbon 13. It follows that hydrocarbons such as those under the Gulf must be preferentially composed of carbon 12. So then the question is, what are the little creatures of the Gulf eating, and is it preferentially carbon 12, or does it have the usual (rather small) proportions of carbon 13.

Turns out that the zooplankton of the Gulf have way less carbon 13 than usual, these days, indicating that they have been eating creatures (ciliates) that have been eating creatures (nanoflagellates) that have been eating creatures (bacteria) that have been eating oil. And that is where the oil has gone.

It is almost certainly a completely clean cleanup, with no harm to the zooplankton or the crabs that eat them and then come to our plates. You can read more in a report from the Dauphin Island Sea Lab.

The natural answers to apparently insurmountable difficulties are sometimes surprising. Makes me think of Hopkins’ verse:

There lives the dearest freshness deep down things…

And though the last lights off the black west went,

Oh morning at the brown brink eastward springs

Because the Holy Ghost over the bent

World broods, with warm breast and with – ah! – bright wings.

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