570 gas plumes or seeps were discovered in the area between Cape Hatteras in North Carolina and Georges Bank in Massachusetts, which covers about 94,000 square kilometers of ocean floor. According to the research paper published in Nature Geoscience on Sunday, the depth of the seeps range from 50 to 1,700 meters, and "440 seeps originate at water depths that bracket the updip limit for methane hydrate stability".
This means that over 400 seeps are at depths wherein methane hydrates (ice-like solids composed of methane and water) could be decomposing due to the rise in ocean temperature, thus releasing what could possibly be methane. Methane hydrates are stable only at low temperatures and high pressures.
The bubbles emitting from the gas plumes have yet to be tested, but Adam Skarke, the study's lead author, told Huffington Post, "We don't know of any explanation that fits as well as methane."
Skarke is a geologist at Mississippi State University in Mississippi State.
The scientists made the discovery when they analyzed the data gathered from sonar scans done in the area from September 11 to August 2013. Skarke said he was surprised at the discovery because "many of the common things associated with methane gas do not exist on the Atlantic margin."
Although methane does not often reach the surface, it can be oxidized to carbon dioxide, which in turn could cause more acidity in the ocean, explained the study's co-author Carolyn Ruppel in the NOAA website.
"It's important to find and understand such seeps because they have global significance for the transfer of methane carbon from long-term storage in ocean-floor sediments into the ocean and atmosphere," she said.
