Dynamik benthischer Ökosystemfunktionen in Abhängigkeit des Schelfeis-Zerfalls im westlichen Weddellmeer

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The Larsen ice shelves east of the Antarctic Peninsula have been retreating rapidly, thus subjecting the manne ecosystem of the western Weddell Sea (Larsen areas A and B) to dramatic changes in environmental conditions: open water allows for higher primary production, higher export of organic matter to the seafloor, and äs a consequence, the seabed has been recolonized at many sites by rieh benthic communities. These differ frorn the impoverished assemblages found in oligotrophic conditions under the ice shelves, which raises the question, how the pronounced changes in benthic food supply and community composition may have influenced benthic ecosystem functioning (BEF)? Important BEF components are the degradation of organic matter and the associated remineralization of carbon and inorganic nutrients. Little is known about this issue in polar regions, and even less how these benthic processes have and will change in response to the continuing retreat of Antarctic ice shelves. This project therefore aims to (1) give a first quantification and (2) determine changes of benthic boundary fluxes on the Larsen shelf after loss of ice shelves (A and B) related to changes in organic matter on the seabed and community composition and (3) evaluate future changes of benthic boundary fluxes on the entire Larsen shelf (A, B, and C) using an experimental approach. As part of the 'Larsen Shelf Study of the Ocean' (LASSO), the outcome of this project will lead to a conceptual model describing the effects of ice shelf retreat on the benthic ecosystems in the Larsen region.