Ecological function of macrobenthic communities, Arctic

Macrobenthos plays an important role in ecosystem processes such as bioturbation, particle reworking and ventilation of the soil. Nevertheless, explaining the relationship between biodiversity and ecosystem function (BEF) remains a difficult task. This holds also true in remote polar regions such as the LTER observatory HAUSGARTEN in the Fram Strait. The local hydrographic regime is mainly influenced by the warm northern-bound West Spitsbergen Current, and the southwards flowing cold and less saline East Greenland Current. The currents are causing regional differences in sea-ice coverage. Distribution patterns of the sea-ice play a major role in determining the flux of potential food to the seafloor, thus shaping benthic communities. Recently, functional and biological trait analysis (BTA) became an important tool to investigate BEF-relationships in marine environments. However, this approach is relatively new for Arctic regions, especially deep-sea ecosystems. Therefore, our study aims to determine functional characteristics on a depth gradient in the deep Fram Strait. Deep-sea samples (1000 – 5500m) were collected in the Arctic autumn of 2018 on board of RV Maria S. Merian. An USNEL box corer (0.25m²) was deployed at nine sites along the bathymetric transect of the LTER observatory HAUSGARTEN offshore Svalbard. All material was treated trough a 0.5-mm sieve and fixed in 4% formalin. The specimens were identified to species level wherever possible and after assigning to modalities of selected traits used for BTA to observe functional changes along the depth gradient. Preliminary results on community structure and resulting functional differences between the benthic communities will be presente