Glass sponge communities and the role of their environment in the Weddell Sea, Antarctica
Glass sponges (Porifera, Hexactinellida) are one of the oldest existing animal groups. Today, these marine sessile filter feeders mainly inhabit the deep sea, but they also occur in considerable numbers on the Antarctic shelves and along the eastern North Pacific coast. Especially in the Antarctic, they are of substantial ecological relevance, as vast sponge beds dominate the benthic biomass of some areas where they play a significant role in silicon cycling and provide structural heterogeneity for a diverse associated fauna. It is still unknown, however, which factors determine glass sponge distribution and, consequently, how environmental changes might affect Antarctic glass sponge communities. In order to fill these knowledge gaps, we conducted video transects using a remotely operated vehicle (ROV) and measured various environmental parameters at corresponding stations in the Weddell Sea during expedition PS82 with RV Polarstern in January/February 2014. First results suggest a connection of glass sponge occurrence with bottom water temperatures and dissolved silicate, factors also considered important for glass sponge distribution in western Canada. In this presentation, some preliminary results on glass sponge abundance and community composition are discussed in relation to abiotic (water mass characteristics, currents, pack ice cover, dissolved silicate) and biotic factors (food, predators) to assess their role on glass sponge distribution in the eastern Weddell Sea.
PS > 82