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R.V. Pelagia - Dust 2023

During the marine expedition “Dust-2023” on the Dutch research vessel the R.V. Pelagia, research will be carried out as part of the German Science Foundation funded cluster of excellence “The Ocean Floor - Earths uncharted interface” research Units RECEIVER and RECORDER.

R.V. Pelagia
R.V. Pelagia (photo with courtesy of the Royal Netherlands Institute of Sea Research, Prof. J-B. Stuut)

During the cruise groups from the MARUM/University of Bremen, the free University of Amsterdam and the Royal Nertherlands Institute of Sea Research (NIOZ) will perform joint investigations in the upwelling region off Cape Blanc and south of the Cape Verde Islands.

Sediment trap
Recovery of one of the MARUM sediment traps (photo Karin Zonneveld)

They will study the relationship between climate change induced changes in Saharan Dust input and upwelling intensity and the production and export flux to the sea floor of marine and terrestrial particulate organic matter. For this the formation, sinking, lateral advection and alteration of particulate organic matter and their environmental proxies in the water column and surface sediments will be studied. For this the production, sinking and alteration processes of the particles will be studied in relationship to upwelling intensity, dust input, ambient redox conditions and the presence of nepheloid layers. Results shall be compared to long-term particle flux and dust records collected by sediment-traps and dust buoys.

The laterally and temporally highly dynamic Cape Blanc upwelling region, is one of the most productive regions in the world and is a key player in the global carbon cycle. Upper waters are fertilized by the input from nutrients into the photic zone as a result of deeper waters upwelling to the surface and the input from terrestrial derived nutrients in the form of dust that has its origin in the nearby Sahara desert. Upper water primary production drives the biological pump which is largely controlled by sinking behaviours and lateral transport of marine snow, particle aggregates and fecal pellets. However, today we still largely lack a quantitative understanding about processes that steer production, sinking velocities, lateral transport and transformation of particulate organic matter. Furthermore we only start to understand the effect of human induced climate change and increase in pollution in this region.

Dust Buoy
Recovery of the NIOZ Dust Buoy "Carmen" on the R.V. Maria S. Merian during expedition MSM104 (2021, photo Karin Zonneveld)

The MARUM team investigates these interactions by investigating the sinking particle flux variability in relationship to natural and anthropogenic induced environmental and climatic changes in the region by executing a long term export particle flux monitoring survey. This unique survey is the world-wide longest monitoring program that has continued since 1988. Since the year 2013 the Royal Netherlands Institute of Sea Research deploys dust collecting buoys at the location of one of the MARUM mooring sites. This enables us to establish a direct correlation between changes in particle export flux and composition with variability in Saharan Dust input.

Apart from servicing the sediment trap moorings the MARUM team will perform investigations on current particle production in the upper water column, the sinking behavior (transport) through the water column and preservation/degradation at the ocean floor. For this, the particle flux from the upper water column will be sampled with free drifting traps that float with the upper water currents. Furthermore the team will study the particle content of deeper water layers and on and in ocean floor sediments in relationship to ambient environmental conditions and redox environment. Variability in particle flux and composition will be studied to obtain insight into the ecosystem change in relationship to natural and anthropogenic induced changes in climate and pollution.

cruise track of cruise Dust-2023
Cruise track of cruise "Dust-2023"