Benthic fauna and functional traits along a Polar Front transect in the Barents Sea – Advancing tools for ecosystem-scale assessments

One of the challenges for large-scale, long-term ecological assessments lies in the integration of faunal datasets. A comparison was made between various ways of analysing benthic macrofaunal datasets using both taxon names as well as functional traits. The sampling stations were located on both sides of the average location of the Polar Front in the Barents Sea, and included the Spitsbergen Bank, slope areas and the deeper basins Storfjord Trough and Hopen Trough. Taxon richness and overall faunal biomass were highest at the shallowest stations, and lowest in the depressions and ice-influenced areas. The overall functioning of the faunal communities reflected the habitat type. In the trough areas, the sediment mixing depth was greatest, reflecting the bioturbatory activities of the fauna. The shallow, gravelly, erosion areas on the Spitsbergen Bank supported mostly surface-active taxa, consistent with the relatively low biological mixing depths. The mixed sediments of the slope environments supported a mixture of surface-active and bioturbating taxa. Functional trait coding offers an additional tool for mesoscale characterisation of communities, particularly for large-scale or long-term datasets, where taxonomic identifications may not be compatible. The results are discussed in terms of future research needs, in light of changing ecological conditions in the Barents Sea, as well as the need for refining environmental assessment tools.

► Functional group analyses improve ecological information in faunal analyses.
► Functional group analyses indicate ecological niches.
► Distribution of taxa is more geographically influenced.
► We propose an approach to assess long-term ecosystem change using benthic datasets.