Oct
3
OH NO! The Critters Are Eating the Oil!
October 3, 2008 | 1 Comment
Much to no well-learnt biologist’s surprise there are creatures in the sea eating crude oil that seeps to the surface off Southern California. David Valentine of UC Santa Barbara and Chris Reddy of Woods Hole Oceanographic Institution in Massachusetts will report in a paper to be published this past Wednesday in the Oct. 1 edition of the journal Environmental Science & Technology the details of what they saw the microbes eating (surprise here) on the half-mile deep seafloor off the Santa Barbara coast. (video .avi 1:00 min)
Oil Drop Seeps Off Santa Barbara
“It takes a special organism to live half a mile deep in the Earth and eat oil for a living,” said Valentine, an associate professor of earth science at UCSB. “There’s this incredibly complex diet for organisms down there eating the oil. It’s like a buffet.”
What do you suppose the “byproduct” is? “They’re eating the oil, and probably making natural gas out of it,” Valentine said. “It’s actually a whole consortium of organisms – some that are eating the oil and producing intermediate products, and then those intermediate products are converted by another group to natural gas.”
Reddy, a marine chemist at Woods Hole, said the research provides important new clues in the study of petroleum. “The biggest surprise was that microbes living without oxygen could eat so many compounds that compose crude oil,” Reddy said. “Prior to this study, only a handful of compounds were shown, mostly in laboratory studies, to be degraded anaerobically. This is a major leap forward in understanding petroleum geochemistry and microbiology.”
From a hard science view the microbes are consuming something over 1000 of the 1500 compounds the researchers have catalogued so far and likely many more. The project is 7 years old using one of the “best” petroleum seep fields known off the Santa Barbara Coast. About two miles out the sea floor is leaking over 100 barrels per day. Near to the oil platform named Holly, the seepage is known to have been leaking for thousands of years. Valentine explains, “Holly just happens to be near some of these seepage areas, which is fortuitous because we were able to get samples from about a mile deep.”
Sea Floor Oil Seep
The scientists determined how much of the oil was being degraded and digested by the microbes by studying samples from the subsurface, the ocean floor, the mid-water, and then from the surface. They were able to pick apart the differences in the makeup of the oil migrating to the surface through faults from deep below the sea floor using a new technique devised by Reddy.
The microbes prefer the lighter compounds of oil, the gasoline part of the crude oil. They tend to leave behind the heavily weathered residue, which is what makes its way to the surface and, sometimes, to the beaches in the form of tar. “There always seems to be a residue,” Valentine said. “They (bacteria) hit a wall. There seems to be stages in which they eat. There’s the easy stuff – the steak. And then they work their way to the vegetables, and then garnish, and then they stop eating after awhile. Just depends on how hungry they are and what’s fed to them.”
Another interesting part is Reddy’s new diagnostic technology is called a comprehensive two-dimensional gas chromatography (GCxGC). Chromatography involves heating up a sample and putting it into a column around 60 meters long. Compounds are then separated based on their boiling points, which works well with light crude oil. With the two-dimensional test, the compounds are put into a cooled trap, for about 10 seconds, and a flash pulse of hot air releases them into the second column. This two-dimensional separation allows the scientists to pick out the many thousands of compounds.
“This new technology was actually too good at its job,” Reddy said. “It was able to separate and help identify significantly more compounds in the oil samples than traditional analytical techniques. The end result was that we were handcuffed with too much data afforded by the GCxGC. However, we overcame this hurdle by using new algorithms to help us interpret the data, which in turn led us to these milestone discoveries.”
The next step is they will follow the oil diet in the laboratory under controlled conditions and track the oil after it forms slicks at the sea surface. The team wishes to know where the totality of the oil has gone as its not all tar on the Southern California beaches.
Perhaps even more important is the genomes the team could now contribute. The press release and one assumes the paper will not discuss the potential the gene pool the microbes offer science. But microbes that eat light petroleum and if they find some eating the heavier compounds might go far to being solutions for heavy oil or tar sand petroleum production and other not yet conceived uses and processes.
This is a very long-lived study. George Wardlaw, the lead author of the paper, is a graduate student in the Marine Science program at UCSB. The other co-authors were J. Samuel Arey of the Swiss Federal Institute of Technology, and G. Todd Ventura and Robert K. Nelson, both of Woods Hole Oceanographic Institute.
This could be very significant research and have many spin-offs of high value. With a seven year life to date and more goals to achieve it is a remarkable team worthy of professional note as well as the science discoveries.
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