Antarctic Benthic Communities Under the Influence of Different Ice Regimes

• Main Author: Kuvshinova, Olga
• Format: Thesis
• Language: English
• Published: 2013
• Subjects: Antarctic; Antarctic Peninsula; The Antarctic; Weddell; Weddell Sea; Antarc*; Ice Shelves; Sea ice
• Online Access: https://oceanrep.geomar.de/id/eprint/27843/; https://oceanrep.geomar.de/id/eprint/27843/1/2013_Kuvshinova-Olga_MSc-Thesis_Antarctic.pdf; https://oceanrep.geomar.de/id/eprint/27843/2/2013_Kuvshinova-Olga_MSc-Thesis_Antarctic_Appendix.pdf

Ice in its different forms affects benthic communities in polar regions directly and indirectly. In order to recognize effects of ice on benthic communities this thesis analyses benthos on the high Antarctic shelf of the southeastern Weddell Sea, a typical high Antarctic habitat, influenced by seasonal sea ice coverage, benthic communities in the Larsen A/B embayments, being covered for hundreds of years by thick ice shelves, which in 1995 and 2002 disintegrated, thus providing large areas to be colonized newly by benthos, and benthos communities form the shelf at the tip of the Antarctic Peninsula, an habitat that can be considered as being unaffected by ice. The benthos in these three subregions revealed distinct differences in densities, biomasses, production, with lowest values in Larsen (680 Ind m-2,78 g wet weight m-2, and 1.7 g C m-2 y-1, respectively). Organism densities at the tip of the Peninsula were slightly higher as compared to the southeastern Weddell Sea Shelf (2767 Ind m-2 vs. 2534 Ind m-2), whereas biomass and production were higher on the southeastern Weddell Sea Shelf than at the tip of the Peninsula due to the dominance of large growing suspension feeders. The normalized biomass size spectra (NBSS) of the benthic communities in the three subregions thus exhibited significant differences in their size structure which could be associated with the different ice regimes and input of organic carbon. The slopes of the NBSS ranged from -0.22 on the southeastern Weddell Sea Shelf to -0.34 in Larsen and -0.50 at the tip of the Peninsula, indicating that macrobenthic communities in the SEWSS are dominated by large-bodied organisms such as suspension feeders (i.e. sponges, tunicates and bryozoans). Contrasting the benthic communities in Larsen and the tip of the Peninsula were dominated by small-bodied organisms such deposit feeders. This study clearly shows pronounced differences in structures, composition and densities/biomasses in the benthic communities in the three subregions which can be ...