Beschreibung: Marine heat flow data provide fundamental insights into thermal processes and advective heat transport occurring near and below the seafloor. Processes that influence and are influenced by heat transport within seafloor sediments and basement rocks include: - the thermal evolution of the oceanic crust and lithosphere; - the geodynamics of plate boundaries and mantle convection; - fluid circulation and associated impacts on water-rock interactions, seismicity, tectonics, and magmatism; - occurrence and stability of gas hydrates; - maturation of hydrocarbons at passive margins. Understanding these processes involves the quantification of energy and fluid fluxes, requiring knowledge of the thermal state deduced from observations that include heat flux, sub-bottom temperature, and thermo-physical sediment properties. Our main objective is the presentation of methods, instrumentation, and recent and on-going projects to demonstrate the wide-range field of application. The Faculty of Geosciences and MARUM (University of Bremen) have a longstanding record of high-quality research in the field of marine heat flow studies. We present exemplary case studies from our field of expertise relating to subduction zones (seismogenic zones), gas hydrates, hydrothermal processes (Layer 2A, fault zones, fracture zones), and ridge related processes. Further on, economical projects like assessment and monitoring of thermal impact of buried off-shore power cables from wind farms on the environment come into focus.