Scientists have identified hundreds of sites off the East coast of the United States where gas is seeping out of the ocean floor. In research published in Nature Geoscience, researchers show that between Cape Hatteras in North Carolina and Georges Bank in New England, there are 570 seeps, an incredible number for an area where previous research had only identified three gas seeps.
The gas is believed to be methane, one of the the most potent greenhouse gases in the world. But because the seeps occur at depths between approximately 160 feet and 5,500 feet, the methane isn’t getting into the atmosphere. "The methane is dissolving into the ocean at depths of hundreds of metres and being oxidised to CO2,” lead author Adam Skarke told the BBC, adding that they also found no evidence that the resultant CO2 was entering the atmosphere.
The source of the supposed methane is still unknown. Some of the gas could be coming from reservoirs of gas or oil, but the picture is still murky. Most of the seeps, according to the New York Times, occur in an even narrower band, between 800 and 2,000 feet, shallow enough that warming seawater might be causing methane to start bubbling up from melting an icy material called methane hydrates that formed around some of the seeps on the sea floor.
Skarke and his fellow researchers don’t think this is a new phenomenon either. They estimate in the paper that some of the seeps may have been around for over 1,000 years, and that there might be tens of thousands more scattered around the world. This potentially high number of methane seeps could, as the Washington Post points out, mean that we are dealing with a “significant and heretofore unknown” new source of greenhouse gases.