Scientists are "extremely surprised" that methane gas levels in the Gulf of Mexico have returned to near normal only months after the massive BP oil spill.
In June, methane gas was 100,000 times more than normal levels. Bacteria quickly consumed the gigantic gas plumes – over 200,000 metric tons of dissolved methane.
Researchers at Texas A&M University and the University of California, Santa Barbara will publish their findings in Science.
"What we observed in June was a horizon of deep water laden with methane and other hydrocarbon gases," David Valentine of U. California said. "When we returned in September and October and tracked these waters, we found the gases were gone. In their place were residual methane-eating bacteria, and a 1-million ton deficit in dissolved oxygen that we attribute to respiration of methane by these bacteria."
John Kessler of Texas A&M added, "Based on our measurements from earlier in the summer and previous other measurements of methane respiration rates around the world, it appeared that (Deepwater Horizon) methane would be present in the Gulf for years to come. Instead, the methane respiration rates increased to levels higher than have ever been recorded, ultimately consuming it and prohibiting its release to the atmosphere."
"This tragedy enabled an impossible experiment," Valentine added, "one that allowed us to track the fate of massive methane release in the deep ocean, as has occurred naturally throughout Earth’s history."
Scientists fear that large amounts of methane stored in the ocean floor would be released to the atmosphere, which would severely add to climate change. This research shows the opposite – that methane releases will not influence climate.
Researchers collected thousands of water samples at 207 sites over 36,000 square miles. The researchers based their conclusions on measurements of dissolved methane concentrations, dissolved oxygen concentrations, methane oxidation rates and microbial community structure.
The National Oceanic and Atmospheric Administration (NOAA) funded the research through a contract with Consolidated Safety Services Inc, the Department of Energy and the National Science Foundation.
Gulf Ecosystem Not Out of the Woods
The good news about methane levels doesn’t mean the Gulf ecosystem is healthy, as BP and others would have us believe.
As reported in The Nation, among scientists’ most striking findings are graveyards of recently deceased coral, oiled crab larvae, evidence of bizarre sickness in phytoplankton and bacteria, and a mysterious brown liquid coating large swaths of the ocean floor, snuffing out life underneath.
All are worrying signs that the toxins that invaded these waters are not finished wreaking havoc and could, in the months and years to come, lead to consequences as severe as commercial fishery collapses and even species extinction.
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