Is oil actually good for sea life?

Where oil seeps naturally from the seabed and bubbles up to the surface, phytoplankton thrive, according to new research. But this doesn't mean that oil, wherever it comes from, is always a biological boon.

Gerald Herbert/AP
Oil can be seen in the Gulf of Mexico, April 2010, more than 50 miles southeast of Venice on Louisiana's tip, as a large plume of smoke rises from fires on BP's Deepwater Horizon offshore oil rig.

Naturally occurring oil vents in the sea floor, releasing hundreds of thousands of barrels of oil into the Gulf of Mexico each year, may actually benefit living organisms, states new research published Monday in Nature Geoscience.

As well as considering the impact of oil seepage itself, the researchers drew comparisons with the impact of oil released by the 2010 Deepwater Horizon spill.

But perhaps the most intriguing question raised by the study is whether oil itself can ever actually be a boon for life, and does this change our perception of oil spills?

With regard to Deepwater Horizon, the amount of oil pouring into the Gulf of Mexico totaled 4.3 million barrels, compared to an annual natural rate of 160,000 to 600,000 barrels.

"This information gives us context for the Deepwater Horizon spill," said co-author Ian MacDonald, an oceanographer and professor at Florida State University. "Although natural seeps are significant over time, the spill was vastly more concentrated in time and space, which is why its impact was so severe."

One of the first insights came as lead author Nigel D’Souza, then a postdoctoral researcher at Columbia University, was cruising over the Gulf of Mexico in a ship, observing chlorophyll fluorescence, a characteristic of certain phytoplankton.

In what he described as “a eureka moment,” he noticed how much more abundant the phytoplankton were when found above natural oil seeps.

In fact, they were almost twice as concentrated as phytoplankton found even a few kilometers away.

In seeking to explain this effect, the researchers say it is unlikely to be the direct impact of oil itself, says Andrew Juhl of Columbia University’s Lamont-Doherty Earth Observatory and coauthor of the study, in a telephone interview with The Christian Science Monitor.

“In general, oil seems to be uniformly negative for phytoplankton in terms of its direct effect.”

So why the explosion of life above the sea vents? The answer lies in a “peculiar interaction of different things,” says Dr. Juhl.

Deep water is heavily laden with nutrients, usually inaccessible to life-forms living near the surface. But as oil bubbles up from the seabed, it agitates these nutrients and carries them upwards.

It is, therefore, this nutritional boost that allows the phytoplankton to thrive.

So, does this mean that oil spills are a good thing, after all? Hardly, according to Juhl.

“If you had an anthropogenic oil spill from a tanker or pipeline, you wouldn’t have the positive effects of oil because it wouldn’t be carrying with it the nutrient-rich water,” says Juhl.

“Above a natural oil seep, you can see a sheen of oil on the water, you can even smell it on the surface, but it’s still a very small amount of oil in comparison to the kind of oil spills that make the news.”

What makes this research so interesting, then, is not any reversal on our understanding of how damaging oil spills can be. Instead, it marks the first time research has been able to draw conclusions between what happens at oil vents, deep down on the ocean floor, and the effects near the water’s surface, sometimes with a mile of water separating the two.

As Juhl says, “this is likely to happen worldwide.”

You've read  of  free articles. Subscribe to continue.

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.