UCSB earth science professor David Valentine printed an article in the journal Science last week responding to a study discrediting the findings of his team’s research regarding chemical dispersants used to combat methane releases from last summer’s Deepwater Horizon gulf oil spill.
The environmental disaster resulted in 200 million barrels of oil spilling into the Gulf of Mexico, increasing methane levels up to 100,000 times above the normal amount. Although Valentine’s study — published by the same journal in January — indicated that abnormally large blooms of methane-consuming bacteria had reduced the Gulf of Mexico’s methane and oxygen levels, a University of Georgia research team led by marine ecology professor Samantha Joye attributed the lowered presence of oxygen to other factors such as the dead-zone phenomenon.
According to Valentine, Joye’s work with Texas A&M oceanography assistant professor John Kessler does not refute the hypothesis of his original study.
“We couldn’t find the methane that had been there earlier,” Valentine said. “The values added up with the oxygen levels that we expected to find. It was all very consistent with the blooms of bacteria that we then found — they were dying because they had consumed all their food but they were still there.”
The team’s research included searching for methane and measuring oxygen levels to see if they were equal to the amount of oxygen that would have been left behind if bacteria had been consuming the chemical. Although the University of Georgia researchers indicated Valentine’s group had made an error during their research, Valentine said the claim is unsubstantiated.
“One of the original arguments is that we missed the plume and were studying the wrong thing,” Valentine said. “I have very little doubt that we were studying the right plume.”
Valentine said the team’s response featured in Science will provide a detailed outline individually addressing each objection.
“We just went point by point and argued where their work is flawed,” Valentine said. “They are using information from the response effort that has since been proven to be false so there are problems with their math as well as their starting point.”
According to Valentine, the initial study’s explanation for the change remains accurate.
“What they’re saying is that they have alternative explanations,” Valentine said. “The bottom line is that nobody has seen a whiff of methane. We have seen where the plume went. Now, where did the methane go?”