Researchers have unexpectedly discovered over 500 methane vents on the bottom of the sea in the East Coast seeping methane into the environment. Scientists have previously found only three methane vents along the seafloor of the East Coast. This new discovery shows that there is probably quite a lot of methane being released that was not previously noticed, but is contributing to global warming.
The methane that is being released through these vents are currently contained in a form of ice called methane hydrate. There may be as many as 30,000 of these vents in the world that we don't already know about, the researchers say.
The researchers studied the sea bottom along the continental margin, or the area of ocean that lies between the coast line and the deep ocean.
Between North Carolina and Massachusetts alone, the team found more than 570 methane vents, far more than they were expecting.
"It is the first time we have seen this level of seepage outside the Arctic that is not associated with features like oil or gas reservoirs or active tectonic margins," said Professor Adam Skarke, the lead author of the study. He is a professor at Mississippi State University.
The scientists have not yet tested the gas emitting from the vents for methane. However, they say it is extremely likely the gas is methane judging from the evidence they can see now.
The majority of vents they found were 500 meters below the sea floor, the right conditions to create methane hydrate, a sludgy ice that contains methane.
The research team speculated that the rising temperatures in the ocean caused by global warming was causing more of these vents to form and emit gas. The methane gas released from the vent does not appear to be reaching the surface, scientists say.
"The methane is dissolving into the ocean at depths of hundreds of meters and being oxidized to CO2," said Skarke. However, he said it was important to acknowledge that his team had not found any evidence that this methane was reaching the surface.
Methane gas is one of the largest contributors to global warming. The Environmental Protection Agency (EPA) says that its effect on climate change is 20 times greater than the same weight of carbon dioxide.
Skarke stated that it could be possible a large reserve of gas under the sea floor was responsible for the vents. However, he said it was unlikely that it was a conventional gas source like the type used by oil companies. "So there is no evidence to say they are a recoverable resource," Skarke said.
