Scientists have recently discovered enormous underwater methane pockets located all throughout the oceans. Abiotic methane is created when slow moving seawater becomes trapped in a hot, rock-forming mineral called olivine-a key component of the earth's upper mantle-when the minerals begin to cool, the water stored inside the rock undergoes a chemical reaction called, serpentinisation, producing both methane and hydrogen.
Scientists studied pieces of rock originating from all across the oceans. The rocks are samples of the earth's upper mantle as well as the lower oceanic crust. One hundred sixty individual samples were collected from areas such as the Mariana forearc and uplifted sections of oceanic crust called ophiolites.
"Identifying an abiotic source of deep-sea methane has been a problem that we've been wrestling with for many years," says marine geochemist Jeffrey Seewald from the Woods Hole Oceanographic Institution, or WHOI.
"Here's a source of chemical energy that's being created by geology."
Once the methane has been created, researchers say it can remain "over geological timescales until extracted by dissolution or fracturing of the olivine host".
It is known that methane has also been found on Mars and other distant planets as well. "Because fluid inclusions may form in olivine-rich rocks that interact with water on celestial bodies elsewhere in our Solar System, their formation may have key implications for the maintenance of microbial life beyond Earth," the authors write in their paper, noting that the release of these fuel sources from the rocks could possibly sustain life in places with rather limited sources of microbial sustenance.
"Present-day release of trapped volatiles by these mechanisms may provide sufficient H2 [hydrogen] and CH4 [methane] to supply microbial ecosystems with electron donors in natural environments where H2 or CH4 formation would otherwise not be favorable."
Here in our oceans, scientists believe that this process "has been occurring since the onset of plate tectonics," and "may have supported microbial ecosystems within diverse geologic environments".
While the scientists are not exactly 100 percent positive that their origin hypothesis is correct, they are however certain that they may have discovered an incredibly large reservoir of methane gas.
"Extrapolation of our results globally suggests that inclusions may represent one of the largest sources of abiotic CH4 on Earth," the researchers conclude.
