hundreds of gas plumes bubbling up from the seafloor were spotted during a sweeping survey of the U.S. Atlantic Coast.
Even though ocean explorers have yet to test the gas, the bubbles are almost certainly methane, researchers report today (Aug. 24) in the journal Nature Geoscience.
The researchers did find some deeper methane vents, at which the ROV Jason glimpsed patches of methane hydrate. This is the icy mix of methane and water that appears when deep ocean pressures and cold temperatures force methane to solidify.
-- Without more exploring, the researchers can't say for sure why there are so many methane plumes along the Atlantic coastline. "It's a huge research area that needs to be pursued," Ruppel said.
"These processes may be happening in places we didn't expect them," -- Interest is running high because the seeps could be a laboratory for studying how methane hydrates respond to climate change.
-- Millions of tons of methane are frozen in Arctic permafrost, both on land and in the seafloor. Recently, several studies have warned that rapid warming in the Arctic could upset these deposits, melting them and freeing the gas. This would boost the planet's greenhouse gas levels and could accelerate climate change.
-- scientists think the East Coast seeps don't contribute much methane to climate change. -- Most of the methane gas dissolves in the ocean before reaching the surface, -- Even though the methane may not escape to the atmosphere, the gas still adds to the ocean's overall carbon budget — which is still a wildly uncertain number.