Arctic permafrost carbon largely buried in seabed, study shows

Scientists studying the effects of Arctic permafrost thaw have found that the ancient carbon released into the ocean is largely sequestered in the seabed rather than released as greenhouse gases. Sediment cores taken off Canada’s Herschel Island show that only about one in ten of the carbon particles that enter the marine environment are converted by microbes into methane or carbon dioxide.

The research, which examined layers of sediment deposited over the past several thousand years, indicates that the majority of the carbon is trapped in the seafloor’s anoxic layers, preventing it from contributing directly to atmospheric warming. While the remaining 10 percent does become gaseous, the overall flux is smaller than previously feared, suggesting that the immediate climate impact of permafrost thaw may be less severe than some models predict.

These findings provide a more nuanced understanding of the Arctic carbon cycle and underscore the importance of monitoring both terrestrial and marine processes as the region continues to warm. The study offers a cautiously optimistic view that natural sedimentary processes may mitigate some of the greenhouse gas emissions expected from thawing permafrost.