Permafrost erosion on shallow subsurface sediment at Herschel Island

The Arctic permafrost has been identified as a critical global tipping element in a warming climate. Coastal permafrost erosion releases between 5 and 14 Tg of organic carbon (OC) annually into the Arctic Ocean. Once discharged into the ocean and redeposited on the ocean floor, the fate of permafrost organic matter remains largely unclear. Despite its significant potential to release previously stored carbon back into the atmosphere, the process is accelerated by anthropogenic climate change. We quantified the dissolved inorganic carbon (DIC) composition and microbial community of nearshore sediments off Herschel Island in the Canadian Beaufort Sea. Our data indicate that redeposited permafrost OC can be readily utilized in the subsurface. Considering the tremendous size of the eroding coastal permafrost reservoir even the conservative ~27% contribution may have a long-lasting effect on the global climate, increasing the climate crisis.