Valentine, who supervised Farwell's research, said, "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."
In an earlier paper published in 2008, Valentine and Reddy documented how microbes devour many of the compounds in the oil emanating from the seeps. The new study examines the final step in the life cycle of the oil.
"One of the natural questions is: What happens to all of this oil?" Valentine said. "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?"
Based on their previous research, Valentine and Reddy surmised that the oil was sinking "because this oil is heavy to begin with," Valentine said. "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."
An all-night sampling marathon on the research ship R/V Atlantis, funded by the National Science Foundation, provided the means to test that hypothesis. With Farwell and Reddy leading the way, the team used what Reddy called an "old school" sampling device to take 16 sediment samples from the ocean floor, following a carefully calculated path mapped out by Farwell. The researchers were hoping that their route, described by Farwell as a "rectangle along the coast from Santa Barbara to Point Conception," would match the trail of the plume. Farwell's calculations were perfect, Valentine said. The 16-point route yielded an unmistakable pattern of oil-saturated sediment all along the ship's path.
The scientists then painstakingly analyzed the samples using Reddy's comprehensive two-
|Contact: George Foulsham|
University of California - Santa Barbara