First underwater methane leak discovered near Antarctica
Just below the freezing Antarctic ice shelves, researchers have discovered a gas leak that could change the region’s climate destiny. For the first time scientists have detected an active leak of methane gas, a greenhouse gas with 25-times more climate-warming potential than carbon dioxide, in Antarctic waters. While underwater methane leaks have been detected previously all over the world, hungry microbes help keep that leakage in check by gobbling up the gas before too much can escape into the atmosphere. But that doesn't seem to be the case in Antarctica.
The researchers found that methane-eating microbes took roughly five years to respond to the Antarctic leak, and even then they did not consume the gas completely. The underwater leak almost certainly sent methane gas seeping into the atmosphere in those five years, a phenomenon that current climate models do not account for when predicting the extent of future atmospheric warming.
The recent leak, located about ten metres deep in the Ross Sea, near Southern Antarctica’s Ross Ice Shelf, was discovered by chance when civilian divers happened to swim by in 2011. The seabed showed telltale signs of a methane leak: white ‘mats’ of microorganisms that exist in a symbiotic relationship with methane-consuming microbes stretched out in a 70-metre line along the seabed.
A sediment analysis confirmed the obvious: methane was escaping from below the seabed. Five years later more microbes had appeared, but the methane continued to flow. Scientist Andrew Thurber called the discovery “incredibly concerning,” as most climate models count on methane-eating bacteria to remove this underwater threat almost immediately. This slow microbial response, coupled with the leak’s shallow depth, suggests that significant amounts of methane have been pouring into the atmosphere above the Ross Sea for years.
In big-picture terms, this is just one small leak, and it probably won’t tip the climate scales in any significant way. But the waters around the southern continent may contain as much as 25 per cent of Earth’s marine methane, and more leaks could be occurring right now without anyone knowing. Understanding how Antarctica’s submarine greenhouse gas stores interact with the ocean and the atmosphere above could have huge implications for the accuracy of climate models.