91̽»¨

The research program of the M208 expedition consists of observations for the Heisenberg Project IOChange and the Program-Oriented Research (POF) of 91̽»¨. The expedition also serves as a preparatory campaign for the FUTURO Project (The Future West African Upwelling System), referred to as FUTUROpre.

The planned research cruise will focus on interdisciplinary work to better understand the dynamics of the eastern boundary upwelling off Northwest Africa, its physical forcing, its importance for biological productivity and plankton communities, and the associated chemical cycles. Furthermore, the atmospheric forcing and the input of dust from the Sahara and their importance for nitrogen fixation and biological productivity will be analyzed. The measurement of aerosols and the meteorological conditions during dust outbreaks during M208 is the second experiment of EXPORT focusing on the transport and deposition of dust near African source regions.

The interdisciplinary measurement program will focus on ocean-atmosphere interactions on small spatial and temporal scales and their impact on biogeochemical dynamics and the ecosystem. The seasonal maximum of coastal upwelling is in March, while the intertropical convergence zone is furthest south and the northeast trade winds are strongest in the eastern boundary upwelling system. It is also a period of increased nutrient inputs from frequent Saharan dust storms. A special focus of the research cruise is the investigation of carbon fixation at the surface and carbon export to greater depths including processes such as particle transport and diel vertical migrations of zooplankton. Possible nitrogen fixation due to selective nutrient uptake and resulting limitation and trace gas production should also be investigated. The investigations into ocean dynamics should in particular study mixing processes at the continental slope and shelf and mesoscale and submesoscale processes and their interaction by using shipboard measurements, short-term moorings and gliders and thus support comparison of in-situ data with SWOT sea level data, other satellite data and output from high-resolution numerical models on upwelling dynamics.