Supplementary material from "Variation in zoobenthic blue carbon in the Arctic's barents Sea shelf sediments"

The flow of carbon from atmosphere to sediment fauna and sediments reduces atmospheric CO₂, which in turn reduces warming. Here, during the Changing Arctic Ocean Seabed programme, we use comparable methods to those used in the Antarctic (vertical, calibrated camera drops and trawl collected specimens) to calculate the standing stock of zoobenthic carbon throughout the Barents Sea. The highest numbers of morphotypes, functional groups and individuals were found in the northernmost sites (80–81.3 N, 29–30 E). Ordination (nMDS) suggested a cline of faunal transition from south to north. The functional group dominance differed across all six sites, despite all being apparently similar muds. Of the environmental variables we measured, only water current speed could significantly explain any of our spatial carbon differences. We found no obvious relationship with sea ice loss and thus no evidence of Arctic blue carbon-climate feedback. Blue carbon in the Barents Sea can be comparable with the highest levels in Antarctic shelf sediments.This article is part of the theme issue ‘The Changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystems'.