Lochlan Breckenridge, Tent Jirapanjawat, Chris Greening, Lyle Whyte
Dormibacterota Decline in Abundance over 14 years of Arctic Warming
Certain bacteria can consume the trace gases hydrogen, carbon monoxide, and methane to survive in harsh environments, which contributes to removing these potent greenhouse gases from the atmosphere. This mode of metabolism is known to aid bacterial survival in Antarctica, but this has not been well studied in the Arctic, and we do not yet know how climate change will affect these bacteria. We hypothesized that permafrost thaw will reduce the relative abundance aerobic trace gas oxidizers. To test this, we analyzed 14-year-old Arctic soil metagenomes and compared them to metagenomes obtained this year from the same site on Axel Heiberg Island, Nunavut. We found that the relative abundance of some key trace gas oxidizing phyla, including Dormibacterota, declined over this 14 year period, and the abundance of key trace gas oxidizing genes declined deep in the soil profile. We also confirmed that these Arctic soils draw down methane and hydrogen, although we do not yet know whether the strength of this trace gas sink is changing. We therefore predict that climate change will disrupt specialized trace gas consuming microbes in the Arctic, which may influence the cycling of trace gases.
