Where Does that Oil Slick Go?

Oil slicks released from Coal Oil Point off Goleta’s coast have made their way into sediments that stretch for miles offshore, according to research conducted by UCSB scientists and the Woods Hole Oceanographic Institution (WHOI). Their research, which is being published in the May 15 issue of the scientific journal Environmental Science & Technology , documents the life cycle of oil and surmises the amount of oil spilled from the Coal Oil Point Reserve to be even greater than that of the Exxon Valdez accident.

The lead author of the study is Christopher Farwell, a UCSB graduate student in marine science and earth science. At the time the research was conducted, Farwell was an undergraduate studying chemistry. David Valentine, a UCSB associate professor of earth science and one of the co-authors of the research, supervised Farwell and said in a written statement, “It’s unusual to have an undergraduate take the lead in such a significant study, and its success is a testament to Chris’s perseverance.”

Additional co-authors of the research include UCSB professor of geography Libe Washburn, and WHOI’s Emily Peacock, Christopher Reddy, and Robert Nelson.

Research also reveals that by the time the oil is buried in the seabed, it is merely a shell of the petroleum that comes from the seep due to its degradation.

“One of the natural questions is: What happens to all of this oil?” Valentine said in a press release. “So much oil seeps up and floats on the sea surface. It’s something we’ve long wondered. We know some of it will come ashore as tar balls, but it doesn’t stick around. And then there are the massive slicks. You can see them, sometimes extending 20 miles from the seeps. But what is really the ultimate fate?”

A paper written by Valentine and Reddy, and published last year, documented how microbes consume many of the oil’s compounds; the recent study examines the final step in the oil process. They believed that the oil was already sinking due to the fact that it was heavy to begin with, according to Valentine. “It’s a good bet that it ends up in the sediments because it’s not ending up on land. It’s not dissolving in ocean water, so it’s almost certain that it is ending up in the sediments.”

“I think it’s giving us a lot of insight into the fate of oil and hydrocarbons in the ocean,” said Washburn in a written statement.

The researchers hope their findings will be well received by those who have studied oil.