The relation between biodiversity and biogeochemical functioning in Arctic deep sea sediments

Although it has been proven that the Arctic is important in the present functioning of Earth and its life and is particularly sensitive to climate change, little is known about benthic ecosystem functioning in the Arctic Oceans. Therefore, to identify the variables structuring benthic functioning, during the summer of 2014 a bathymetric gradient was sampled on both sides of Fram Strait with multiyear ice in the west and a summer ice - free area in the east. The sampled variables included information about the environmental setting, fauna present and biogeochemical fluxes. Ice cover was found to determine the food availability, which in turn affected faunal density, macrofaunal community composition and bioirrigation rate. In summer ice - free areas underneath the marginal ice zone, food availability was higher and therefore meiofaunal density and bio - irrigation were higher as well. Macrofaunal density was only partly explained by food input and total oxygen uptake as a part of benthic remineralisation was mainly structured by silt fraction in the sediment. Water depth determined faunal community composition, with lower macrofaunal biomass and functional diversity in the deeper areas