As the Arctic permafrost melts over the coming decades, long-frozen microorganisms will thaw out and start feasting on the soil. The first have already begun to wake up – and early signs are that they will have a major impact on how Earth's climate changes.
As the escape into the atmosphere.
The question is, will the methane-eaters be able to consume the bulk of the gas once the permafrost starts melting in a big way? Christensen says that will depend on what happens to the water table. Higher water tables mean more methane and fewer microorganisms to eat it, while lower water tables mean the opposite.
No laughing matter
As the team's permafrost samples thawed they saw no boost in the levels of microbes that produce nitrous oxide reductase, an enzyme that converts nitrous oxide into harmless nitrogen. Without this boost, the nitrous oxide could escape.
Christensen has set up a monitoring system to track greenhouse gas emissions from thawing permafrost, and is increasingly tracking nitrous oxide as well as CO2 and methane. "It may be a player," he says.
Journal reference: Nature, DOI: 10.1038/nature10576