Methane plumes off the coast was once incomprehensible and unthought-of, but now a team of researchers has reportedly discovered 500 aerated methane vents just off the U.S.' east coast. Though methane can come from all kinds of places, this recently discovered methane plumes off the coast prove that this part of the world is releasing the gas too.
The discovery was unanticipated, according to Live Science. It was a surprise that hundreds of methane plumes off the coast would be bubbling up during a survey of the U.S. Atlantic Coast.
According to Gizmodo, the team of scientists who discovered the methane plumes off the coast has been studying the continental margin- the region of the ocean floor that stands between the coast and the deep ocean - when they made the discovery.
The scientists reportedly found a series of at least 570 methane seeps on the Atlantic floor, according to sonar and video gathered by the National Oceanographic and Atmospheric Administration ship Okeanos Explorer between 2011 and 2013. The area was between North Carolina and Massachusetts. The Okeanos Explorer made use of sound waves to detect the bubbles from the methane plumes off the coast and map the seafloor.
The findings came as a surprise, said lead study author and Prof Adam Skarke, a geologist at Mississippi State University.
He said, "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."
"It was a surprise to find these features. It was unexpected because many of the common things associated with methane gas do not exist on the Atlantic margin."
In the journal Nature Geoscience, researchers reported on Aug. 24 claims that even though the methane plumes off the coast had not yet been tested by ocean explorers, the bubbles are almost certainly methane.
Prof Skarke said, "We don't know of any explanation that fits as well as methane."
The seeps are sitting at varying depths, between 50m and 1,700m, reports Gizmodo. They are reportedly a result of methane escaping from methane hydrate-an ice form with natural gas locked inside it.
According to Live Science, while these huge canyons etched in the shallow continental shelf served as a hiding place for methane plumes off the coast, they have also become habitat for a diverse ecosystem of methane-loving bacteria.
The seeps were explored in 2013 by a remote-operated vehicle called Jason. Researchers found the seeps to be teeming with crabs, fish and mussel beds.
Methane vents are common around the world, but only three natural gas seeps where methane escapes from seafloor sediments.
The East Coast is reportedly a passive margin, and methane is not thought to come out from its environment. The margin however, hasn't been pulled by plate tectonic activity for millions of years, which means a lack of escape routes for methane.
Study co-author Carolyn Ruppel, chief of the U.S. Geological Survey gas hydrates project in Woods Hole, Massachusetts said, "I usually describe passive margins as cold, old and boring."
Ruppel also said, "It's a huge research area that needs to be pursued."
Researchers cannot conclude for sure the number of methane plumes off the coast until more explorations are conducted.
The researchers said that if the methane plumes off the coast have hidden hundreds of bubbling methane pits, then it's also possible that there are nearly 30,000 more in the world's oceans.
Prof. Skarke said, "These processes may be happening in places we didn't expect them."
Meanwhile, what researchers are getting wrapped up about the recent find on methane plumes off the coast is that it could serve as a laboratory for studying how methane hydrates respond to climate change, reports Live Science.
Methane, a greenhouse gas, disappears in the atmosphere quicker than carbon dioxide. However, it has more warming power than carbon dioxide. Since millions of tons of methane are in the Arctic permafrost, both on land and in the seafloor, it could be a big source to climate change.
According to the researchers' theories, the Earth's gradually warming oceans may now be reaching a temperature where methane escapes from the ice, giving way to a rise of bubbles through the ocean. The team reportedly suppose that there could be as much as 300,000 leaks around the globe, said Nature Geoscience.
Several studies have also warned against the rapid warming in the Arctic which could upset the methane deposits. They could eventually melt and free the gas, thus quickening the planet's greenhouse and accelerating climate change.
In the meantime, scientists believe that the methane plumes off the coast do not contribute all that much methane to climate change. The bubbles they release still haven't been observed to have reached the surface as they appear to dissolve and become oxidised as CO2.
However, methane plumes off the coast are still known to add to the ocean's overall carbon budget, and the numbers are still uncertain.
Ruppel said, "It's not a huge number, but it's an important number for us to know. We simply don't have any evidence in this paper to suggest that any carbon coming from these seeps is entering the atmosphere."
According to the BBC, the research on the methane plumes off the coast highlights the scale of methane below the Earth's oceans and suggests that the current estimates of greenhouse gas sources in the planet may be inaccurate.
These undersea sediments are one of the largest reservoirs on Earth, according to the BBC, and they dangerously contain around 10 times more carbon than the atmosphere.
Methane plumes off the coast may not pose as an immediate threat to global warming, however the sheer number means greenhouse gas source calculations need to be revised. The new fin on methane plumes off the coast will now be serving as stimulus for more research to find out if these plumes are a definite source quickening climate change.
View an astounding gallery of methane seeps here.
