Deep underwater in the Ross Sea off the Antarctic coast, scientists discovered a new active leakage of methane, a much more potent greenhouse gas than carbon dioxide. The discovery marked the first time that scientists were able to directly observe a new leak of methane underwater, and see how microbial life that feeds on methane in its vicinity evolved over a span of five years.
In a study published in the Royal Society B Peer-reviewed Proceedings, a research team led by Oregon State University oceanographer Dr. Andrew Thurber explained that methane gas leak was first discovered in 2011 off the Antarctic coast. Antarctica is believed to have a quarter of the planet’s methane trapped in permafrost and on continental shelves.
Just as microorganisms like fungi reproduce like mad in the presence of a food source in our homes, for example, an open soda can or a jar of open-air jam, microbes that eat methane are present in small amounts scattered across Earth’s oceans and only multiply precipitously when they find a prominent source of “food” such as a methane leak. In fact, scientists point out that by 2016, the methane-consuming microorganisms began to appear from the leak and consumed a small portion of the gas, though not enough to compensate for methane ventilation.
In the case of this methane seepage in the Ross Sea, the researchers tried to quantify the “response rate” of the microbial community over time; in other words, how fast did these microbes establish around the leak and how much methane did they absorb earlier. It could reach the atmosphere. Five years after the leak formed, the researchers noted that the microbial mat “had not yet formed a sufficient filter to mitigate the release of methane from the sediment.”
The discovery is particularly interesting because the chronology of this type of phenomenon is not well understood; Before this article, it was unknown how long it would take for microbial life to filter out methane in a similar methane filtration. The researchers said that five years after the leak formed, the microbes were still in an “early succession stage.”
“This study provides the first report of the evolution of a filtration system from an environment without filtration, and reveals that the rate of microbial succession may have an unrealized impact on the emission of greenhouse gases from marine methane deposits” they wrote.
The presence of methane increases the amount of heat trapped in the atmosphere. From a warming perspective, it is preferable that microbes consume methane first and produce carbon dioxide, which is still a greenhouse gas, although not as potent as methane, which absorbs 25 times more heat in the atmosphere compared to carbon dioxide.
“Our results suggest that the accuracy of future global climate models can be improved by considering the time it will take for microbial communities to respond to the new methane input,” the authors write.
Salon contacted a couple of climatologists to reflect on the study. The common observation, made in the study itself, is that the methane leak itself does not appear to have occurred strictly due to global warming, although that is a scenario that scientists are concerned about.
“This study really demonstrates a potential route by which Antarctic marine methane can escape into the atmosphere,” Dr. Michael E. Mann, a distinguished professor of atmospheric science at Penn State University, told Salon. “It does not show that climate change has led to an increase in methane emissions. Relevant to this last point is a study that just came out for a week and shows that increases in methane in the atmosphere are due to natural gas extraction. (‘fracking’) and methane emissions from livestock. There is no evidence that ‘methane feedbacks’ are contributing to increased methane, at least today. “
Dr. Kevin Trenberth, a distinguished senior scientist in the Climate Analysis Section of the National Center for Atmospheric Research of the University Corporation for Atmospheric Research, made a similar comment in an email sent to Salon.
“Methane concentrations in the atmosphere have increased prominently in recent years, and a major source is from leakage fracturing facilities and the resulting fugitive emissions,” Trenberth explained. After reviewing the economics of fracking during the coronavirus pandemic, and in particular how part of the industry has gone bankrupt, Trenberth responded to the document by writing that “it greatly illuminates natural processes in the southern ocean. Carbon of various types (wood , sea weeds, etc.) decomposes and forms carbon dioxide (if it is aerobic) or methane (if it is anaerobic and submerged in water.) Certain different types of bacteria flourish in both conditions. I understand that a large amount is absorbed of methane from the deep ocean instead of being emitted into the atmosphere. That would be a key question. “
He added: “What surprises me about this article is that the southern oceans are far from being work friendly. There are strong winds and big waves, and how they could even do this work would be of interest … Are their results? As a result biased? In any event, a new and rich new biogeochemistry has evidently been discovered that can only help understand and model. “
