Cruise Leg MSM81 with RV MARIA S. MERIAN, leaving Valparaiso, Chile, on February 2 2019, returning to Montevideo, Uruguay, on March 15 2019, comprised seismic reflection studies of the Falkland Plateau, the westernmost part of the Agulhas-Falkland Fracture Zone in the South Atlantic. The Falkland Plateau rises up 1500 m above the surrounding seafloor and hence forms an obstacle for the exchange of water masses between high and lower latitudes. A water mass exchange between the Pacific and Atlantic oceans has been enabled with the opening of Drake Passage. In this way heat and energy could be transferred between the two oceans. A detailed study and analysis of the structure of the Falkland Plateau and channel in the south via seismic data and a correlation with results from DSDP Leg 36 Sites 327, 329, and 330 as well as Leg 71 Site 511 was needed to supply information on the Cretaceous and Tertiary development of the Falkland Plateau and its influence on the path of the Antarctic Circumpolar Current, Upper and Lower Circumpolar Deepwater, South Pacific Deepwater, and Weddell Sea Deepwater. Seismic profiles were gathered, which capture the structure of the Falkland Plateau to basement and possible sediment drifts. In total ~5200 km of high resolution seismic reflection data were recorded. Bathymetric and Parasound data were recorded parallel to the seismic profiling. To complement the seismic studies SVP and XSV measurements at six locations and ADCP measurements across the whole working area were carried out.