Methane Cycling by Arctic Microbial Communities
Arctic and Antarctic ecosystems host a surprising shift in methane dynamics. Bacteria, algae, and lichens living in cold deserts can switch from acting as methane consumers to becoming methane producers. This discovery comes from research summarized in the journal Science in Siberia, which reports findings from work presented at a conference on Physical and Mathematical Modeling of Earth and Environmental Processes.
Researchers from the Krasnoyarsk Scientific Center of the Siberian Branch of the Russian Academy of Sciences, specifically the Forestry Institute Sukachev SB RAS, collaborated with scientists from the Siberian Federal University to study tundra ecosystems in two distinct locales: the Lena River Delta, in Yakutia, and King George Island in the South Shetland archipelago near Antarctica. The team found that on the Lena Delta islands, algae and lichens consume methane across seasons and regardless of humidity levels. In contrast, a humidity rise to 60 percent on King George Island flips these communities into methane producers and sinks, where mosses and other organisms play a key role. Notably, the moss groups Sanionia sp and Campylium sp tended to resist humidity-driven changes and continued processing methane as before.
These interactions matter because methane ranks as the third most impactful greenhouse gas in the atmosphere. Its contribution to warming is estimated at 5 to 10 percent of total greenhouse forcing, while the greenhouse effect of methane can exceed that of carbon dioxide by a factor of 25 to 30. Moreover, methane concentrations are increasing at a rapid pace, rising three to four times faster than prior trends. The study suggests that every shift in moisture or temperature can alter the balance of methane production and consumption in Arctic ecosystems.
As global warming accelerates the thaw of permafrost, stored organic carbon becomes exposed and methane can be released into the atmosphere. The researchers propose that warming could foster the growth of methane-producing microbial communities in association with mosses and lichens, creating a positive feedback loop that intensifies heat in the region. This cascade would push methane emissions higher and may contribute to further climate change impacts, highlighting the need to monitor microbial responses to environmental shifts in polar regions.
In related developments, scientists with a background in northern research recently reported discoveries of three ancient lichen species from the Pakistani region, expanding understanding of lichen diversity in extreme environments. These findings underscore the broad reach of microbial and fungal life in shaping methane and carbon cycling across distant cold ecosystems. [Citation: Science in Siberia, latest conference proceedings]