Maud Rise - a snapshot through the water column

• Published in: Deep Sea Research Part II: Topical Studies in Oceanography
• Main Authors: Brandt, A., Bathmann, U., Brix, S., Florentino De Souza Silva, A.P., van Franeker, J.A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2011
• Subjects: 1st insights; antarctic krill; atlantic sector; carbon fluxes; deep-sea; drake passage; eastern weddell gyre; pack-ice; pore-water; southern-ocean; Antarctic; Southern Ocean; Drake Passage; Weddell; Maud Rise; Bray; Antarc*; Antarctic Krill; Balaenoptera bonaerensis; Euphausia superba; Sea ice
• Online Access: https://research.wur.nl/en/publications/maud-rise-a-snapshot-through-the-water-column; https://doi.org/10.1016/j.dsr2.2011.01.008

The benthic fauna was investigated during the expedition ANT-XXIV/2 (2007/08) in relation to oceanographic features, biogeochemical properties and sediment characteristics, as well as the pelagic, benthic pelagic and air-breathing fauna. The results document that Maud Rise (MR) differs distinctly from surrounding deep-sea basins investigated during previous Southern Ocean expeditions (ANDEEP 2002, 2005). Considering all taxa, the overall similarity between MR and adjacent stations was low (20% Bray-Curtis-Similarity), and analyses of single taxa show obvious differences in species composition, abundances and densities. The composition and diversity of bivalves of MR are characterised by extremely high abundances of three species, especially the small sized Vesicomya spp. Exceptionally high gastropod abundance at MR is due to the single species Onoba subantarctica wilkesiana, a small brooder that may prey upon abundant benthic foraminiferas. The abundance and diversity of isopods also show that one family, Haplomunnidae, occurs with a surprisingly high number of individuals at MR while this family was not found at any of the 40 bathyal and abyssal ANDEEP stations. Similarly, polychaetes, especially the tube-dwelling, suspension-feeder fraction, are represented by species not found at the comparison stations. Sponges comprise almost exclusively small specimens in relatively high numbers, especially a few species of Polymastiidae. Water-column sampling from the surface to the seafloor, including observations of top predators, indicate the existence of a prospering pelagic food web. Local concentrations of top predators and zooplankton are associated with a rich ice-edge bloom located over the northern slope of MR. There the sea ice melts, which is probably accelerated by the advection of warm water at intermediate depth. Over the southern slope, high concentrations of Antarctic krill (Euphausia superba) occur under dense sea ice and attract Antarctic Minke Whales (Balaenoptera bonaerensis) and several seabird ...