METEOR M135

Previous research efforts conducted by the collaborative research centre (SFB) 754 in the Peruvian shelf Oxygen Minimum Zone (OMZ) region have demonstrated that sediment-ocean interface processes are potentially very important for the biogeochemistry of the OMZ and possibly for the development of the OMZ itself. However, the role of diffusive and advective pathways that connect water within the bottom boundary layer (i.e. the water directly affected by sediment exchange processes) to the pelagic ocean and the surface by enhanced mixing or a potential “fast conduit” to the OMZ interior, remains poorly known. To address this, the scientists of cruise M135 conduct a tracer release experiment on the Peruvian shelf; this cruise will be the main mapping cruise of the tracer that was injected in the end of 2015. The team also retrieves sediment cores at the southern limit of the modern upwelling zone extending along the southern Peru shelf-break to better understand the influence of the Humboldt Current on the extent and intensity of the OMZ. In addition the scientists measure particle abundance in the water column, redox sensitive trace metals and biogeochemical compounds.