Environmental changes in the Barents Sea – Does the invasive snow crab disturb the sediment and geochemical composition in the Barents Sea?

Abstract

The snow crab, Chionoecete opilio, is an invasive species in the Barents Sea. The spread of the species has know environmental impacts on the benthic community, removing species important for biominxing. By analyzing short sediment cores (10 cm) from locations with high density of snow crabs and low densities of snow crabs it is clear that the snow crab effects the benthic community. Both macrofauna and benthic foraminifera indicates sediment mixing in the areas with high crab densities. Foraminifera are single celled organisms found in all marine environments, and the main difference in microhabitat characteristic is between the epifaunal and infaunal benthic organisms. The main factors determining the vertical distribution of foraminifera are oxygen concentration and food availability. Sediment analysis of total organic carbon, water content and sediment size support the evidence of sediment mixing and livable conditions downcore, as the different parameters can be correlated.