Methane-Eating Bacteria: A Possible Cure of Global Warming

UNIVERSITY PARK, Pa. ­— It is no secret that global temperatures are rising. Oceans temperatures are warming. Ice sheets are shrinking. Seal levels are rising. The list of evidence of climate change goes on and on, and according to the Intergovernmental Panel on Climate Change, there is a 95% chance that warming trends are a direct result of human activity over the past 50 years. This is changing Earth’s natural greenhouse.

About half of the light that the earth receives from the sun passes through the earth’s atmosphere and reaches the sun. The light is absorbed by greenhouse gases and then radiated toward the surface of the earth. The problem is that there has been an increase in the concentrations of these greenhouse gases, and as a result, extra heat is being trapped beneath Earth’s atmosphere.

The escalation in activities such as burning fossil fuels, agriculture and deforestation has been a major contributor to the amount of greenhouse gases in the atmosphere. Many people associate carbon dioxide with climate change, and while it is the second largest contributor to global warming, three other gases share the blame. In order from greatest to least, water vapor, carbon dioxide, nitrous oxide and methane are the four main greenhouse gases associated with global warming.

Scientists and climate change aficionados alike have proposed numerous methods to reduce greenhouse gas emissions, whether they are reducing wastewater, investing in energy-efficient appliances and finding ways to reduce a carbon footprint. Recently, researchers from Montana State University, Louisiana State University and Aberystwyth University have found a feasible solution to eliminate some of the methane in the atmosphere: methane-eating bacteria.

The team found the bacteria lurking 800 meters below the West Antarctic Ice Sheet in Lake Whillans. Due to its deep location, Lake Whillans had been secluded from direct contact with the atmosphere for thousands of years. The team collected water and sediment samples, believed to have been deposited into the lake 120,000 years ago. Next, they used genomic analysis to conclude that 99 % of methane released into the lake was depleted by methane-reducing bacteria in the upper lake sediment. The location where the microbes were found suggests that they prevent methane from penetrating the atmosphere as ice sheets recede. According to John Priscu, regents professor at Montana State University and co-author of the study, the results could have a tremendous impact on climate change in the future.

“The results provide new data transforming our view of Antarctica from a continent with no life to one where active aquatic ecosystems are present beneath the ice sheet. It also yields new information on methane release to the atmosphere may be affected as we continue to lose Antarctic ice shelves,” Priscu said.

Although methane is not the most abundant greenhouse gas, it is one of the most potent greenhouse gases and is roughly 30 times more potent than carbon dioxide, according to a study at Princeton University, making the study all the more important.

While Priscu believes in the importance of the results, he says that the results were not expected.

“We hypothesized that subglacial Lake Whillans would be an oligotrophic lake with little organic carbon because there is no photosynthesis to produce new organic carbon,” Priscu said.

When something is said to be oligotrophic, it lack nutrients and offers little to nothing to support life. The remote location and harsh environment of Lake Whillans led researchers to this belief.

Sunlight does not reach Antarctica’s subglacial lakes, which would make it seem as though life would not be supported; however, the microbes in the lake convert methane to carbon dioxide, which traps less heat than methane, to make energy.

Still, information about lakes and rivers beneath Antarctica’s ice sheets is sparse and needs to be explored more to fully understand the impact that the microbes may have on global warming. The team plans to learn more by drilling into a different subglacial lake between 2018 and 2019 to give a more complete overview of these microbes and offer evidence of life on other icy climates, such as the moons of Saturn.