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Geochemist Laura Lapham studies effect of oil spills on microbes in Gulf of Mexico
Assistant Professor Laura Lapham has just returned from a cruise on the Gulf of Mexico to study the impacts of the Deepwater Horizon oil spill. In the aftermath of the spill, BP invested $500 million to fund research into the effects of petroleum and possible methods for restoration and long-term preservation of the marine environment. Lapham is funded as a part of a three-year study which will investigate Ecosystem Impacts of Oil and Gas Inputs to the Gulf (ECOGIG).
The first ECOGIG cruise, aboard the research vessel Endeavor, lasted two weeks this past April. Its purpose was to put out long-term monitoring equipment.
"The Gulf of Mexico is a very unique place because there is a lot of natural oil that is seeping out of the sea floor," said Laura Lapham. "Something I try to understand is how the microbial communities are degrading this oil, and how they respond to this natural seepage of oil."
Petroleum is formed when organic matter, such as dead plants and animals, reaches the seafloor, gets buried over time, and eventually comes into contact with the Earth’s core heat, several kilometers below the sea bed. The heating of this organic matter makes petroleum. Throughout this process, the organic matter loses many of the nutrients it once possessed, which means not many organisms can degrade it or break it down, but microbes can, according to Lapham. Some microbes have evolved to be able to do this.
"In the Gulf, when the oil spill happened, there were a lot of statements like, 'The microbes are ready for it, they're primed to break down this oil and make more benign products that aren't as bad as the oil.' But that’s still a question mark," said Lapham.
These natural microbial communities are used to the slow seeping of oil, but were perhaps not ready for such a large input of oil like what happened with the Deepwater Horizon spill.
To explore the oil spill's effect on these microbes, Lapham will rely on an instrument array that collects water samples from within the sediments. Nicknamed MIMOSA -- which is short for Microbial Methane Observatory for Seafloor Analysis -- her array consists of little probes that stick into the sediment and are connected to instruments that pump samples and store them for subsequent analysis.
"We put two MIMOSA systems out," Lapham says. "One at a natural seep, and then one that was very close to the spill site. That way, we can compare how the communities respond to the natural oil seepage and the large input of oil."
Eventually, she says, they will place a MIMOSA at a reference site that is not impacted by either natural seeps or manmade wells.
The MIMOSA samples, which will be collected during a follow-up cruise in November, are intended to reveal more about the nature of the microbes themselves.
"What does that community structure look like, do you have organisms that grow in right away, that can utilize that oil right away, and then other things come in later?" Lapham asks. "Or is it just one community that can do it?"
She adds that the novelty of this project is that they are addressing these questions with in situ, or 'in place' sampling in the natural environment; they are no longer just in the laboratory. The debate over whether the dispersant chemicals helped or hindered the degradation of the oil will also be examined.
"What does that combination of oil and surfactant do to the microbes," she adds, "Can they degrade that?"
Thinking about the bigger picture, Lapham reflects on what could be learned from all the newly funded GoMRI work, should there be a spill in the future.
"I think what [BP is] trying to do is to say, 'Ok how could we do things differently, what are the factors that we need to know, how would we respond differently?'" she says. "That's my hope anyway."