Benthic organic carbon fluxes in the Southern Ocean: Regional differences and links to surface primary production and carbon export

• Main Author: Sachs, Oliver
• Other Authors: Schlüter, Michael, Schulz, Horst, D.
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Universität Bremen 2007
• Subjects: benthic organic carbon fluxes; deep-sea sediments; Southern Ocean; microsensors; oxygen penetration depth; export ratio; 550; 550 Earth sciences and geology; ddc:550; Antarctic; Indian; Pacific; The Antarctic; Weddell; Antarc*
• Online Access: https://media.suub.uni-bremen.de/handle/elib/2515; https://nbn-resolving.org/urn:nbn:de:gbv:46-diss000110604

Without doubt, global climate change is directly linked to the anthropogenic release of greenhouse gases such as carbon dioxide (CO2) and methane (UN IPCC-Report 2007). Therefore, research efforts to comprehend the global carbon cycle have increased during the last years. In the context of the observed changes, it is of particular interest to decipher the role of the hydro-, bio- and atmospheres and how the different compartments of the earth system are affected by the increase of atmospheric CO2. Due to its huge carbon inventory, the marine carbon cycle represents the most important component in this respect. Numerous findings suggest that the Southern Ocean plays a key role in terms of oceanic CO2 uptake. However, an exact quantification of such fluxes of material is hard to achieve for large areas, not least on account of the inaccessibility of this remote region. In particular, there exist so far only few accurate data for benthic carbon fluxes. The latter can be derived from high resolution pore water oxygen profiles, as one possible method. However the ex situ flux determinations carried out on sediment cores, tend to suffer from temperature and pressure artefacts. Alternatively, oxygen microprofiles can be measured in situ, i.e. at the seafloor. Until now, no such data have been published for the Southern Ocean. During the Antarctic Expedition ANT XXI/4, within the framework of this thesis, in situ and ex situ oxygen profiles were measured and used to derive benthic organic carbon fluxes. Having both types of measurements from the same locations, it was possible to establish a depth-related correction function which was applied subsequently to revise published and additional unpublished carbon fluxes to the seafloor. This resulted in a consistent data base of benthic carbon inputs covering many important sub-regions of the Southern Ocean including the Amundsen and Bellingshausen Seas (southern Pacific), Scotia and Weddell Seas (southern South Atlantic) as well as the Crozet Basin (southern Indian Ocean). ...