In Situ Technologies at MPI and AWI

The sediment surface is characterized by steep gradients and an extensive spatial and temporal heterogeneity. Measurements with high temporal and spatial resolution are crucial for the understanding of early diagenesis, microbe-environment interactions, and benthic fluxes. To determine microbial conversion rates in sediments, and to get insights into their regulation, activity measurements must be complemented by the characterization of the habitat, its microenvironments, the determination of transport phenomena, and substrate availability. The microprofiler unit enables the in situ quantification of such processes in environments where core retrieval severely alters the sediment, such as in gas-laden cold seeps, the deep sea, or highly dynamic environments. more ...

In the highly heterogeneous ocean ecosystem, the sediment-bottom water interface represents a boundary zone that connects the two oceanic realms - the sediment and the water column. At the seafloor, the sediment-water interface is one of the most important transition zones for solute exchange, both in time and space. The benthic chamber module enables in situ measurements of the total exchange rates (e.g oxygen, methane, nutrients, DIC) between the sediment and the water column. This measurement integrates all relevant solute transport processes (diffusion, advection, and fauna-mediated transport). more .....

The sediment-water interface is one of the most important boundary layers of the earth system with crucial filter functions for the mass exchange between the seafloor and the water column. One of the most important exchange processes across this layer is the oxygen flux, which is a fundamental control factor for the biogeochemical activity in the sediment. The eddy correlation system (ECS) allows the measuring of exchange rates across the water-sediment interface in a non-invasive manner, providing direct measurements with temporal resolution of minutes, and a spatial resolution of several meters. more ....