Cruise M615 was a special cruise as it was the first MARUM cruise to be carried out under "Corona Conditions". The excellent cooperation and flexibility of the headoffice Gutachterpanel Forschungsschiffe (GPF), the German Research Fleet Control Centre (LDF) and "Briese Research Forschungsschiffahrt" caused that we were allowed to execute part of the scientific program of cruise M163 (initially planned for April 2020), a cruise that was cancelled because of the Corona outbreak.
After a stay in a Quarantine Hotel in Leer we sailed out in Emden in the first week of August to start a transit of 10 days into the research area; the upwelling region off Cape Blanc. This region is the focus of research activities in the MARUM/GeoB for already more than three decades as it is the location of the long-term sediment trap moorings.
Apart from servicing the two traps, during cruise M165 we were interested in particulate and dissolved organic carbon and processes that steer their turnover and interaction.
Despite the long tradition of MARUM research in the area, many aspects of processes and mechanisms influencing the shape of organic-matter, the (bio-)mineral and vertical particulate flux, their vertical and lateral displacement and transformation as well as the influence these aspects have on their proxy signals are still unknown. This is partly due to the fact that in those three decades never a MARUM cruise studying these aspects had been carried out during the summer season.
During cruise M165 we intended to increase information about these aspects and mechanisms at times of low upwelling activity by sampling data, water and sediments. For this we deployed drifting traps, in-situ pumps, CTD/Rosette and, of course, serviced the MARUM long term sediment trap moorings.
For all investigations, a comprehensive “ecosystem” approach was followed where we tried to follow major representatives of the ecosystem (phytoplankton, zooplankton and microbial community) from their production and activity in the water column towards embedding in the sediments.
After few weeks of intensive scientific program and a transit home of 10 days we arrived back in Emden in the beginning of September, tired but with many good data and samples that are currently being investigated in quite a number of PhD and PostDoc research projects in the MARUM Units Receiver and Recorder.