Climate-Biogeochemistry interactions in the tropical ocean of the NW-African oxygen minimum zone (SFB754) - Cruise No. MSM17/4 - March 10 - April 11, 2011 - Dakar (Senegal) - Las Palmas (Spain)

Freier Zugriff
in MARIA S. MERIAN-Berichte; MSM17/4; 1-59; MARIA S. MERIAN-Berichte

Dokumentinformationen

  • Format / Umfang:
    59 pages
  • ISSN:
  • DOI:
  • Medientyp:
    Aufsatz (Zeitschrift)
  • Format:
    Elektronische Ressource
  • Sprache:
    Englisch
  • Klassifikation:
    DDC:    550 Earth sciences and geology

Abstract

MERIAN cruise 17/4 lead to the upwelling area off Mauritania and Senegal (West Africa). The voyage was dedicated to investigations of the Sonderforschungsbereich 754 (SFB- 754) Climate Biogeochemistry Interactions in the Tropical Ocean at the University Kiel. Investigations were carried out between 12° N and 18°N on 5 depths transects from the shelf (ca. 70m) down the continental slope. The five transects, two in Senegalese, 3 in Mauritanian waters reflected different upwelling intensities. A major objective of the cruise was the in situ measurement of turnover and fluxes of nitrogen compounds, trace metals, phosphate and iron in the benthic boundary layer at variable oxygen concentrations of the bottom water. In parallel to these measurements of the natural environment, the effects of variable oxygen availability (thresholds) in the bottom water on N-speciation and release of nutrients were determined by additional in situ experiments. Further major activities of this cruise comprised biological investigations of the benthos (megafauna, Foraminifera, bacteria) as well as paleo-oceanographical and paleo-climatological studies. Oxygen threshold will be compared with changes in benthic faunal population structures. In the water column we investigated the import and distribution of Sahara dust as source for micro-nutrients. Oxygen-dependent biogeochemical pathways of the nitrogen cycle, such as nitrogen fixation and N-loss processes (denitrification, annamox) were studied in detail.