Combination of multibeam backscatter and bathymetry: A method to characterize the seafloorA high resolution multibeam survey was conducted by the RV "Polarstern" in order to identify and map locations of carbonate mounds in the Porcupine Seabight west of Ireland utilizing the multibeam echo sounder Hydrosweep DS-2. The scientific interest of that area rose due to an expected link between the carbonate mounds and subsurface hydrocarbon resources. In addition to the depths measurements the acoustic intensity of the received echo was recorded for individual measurements.After processing of the echo amplitudes by employing NRGCOR software the backscatter strength of the ensonified seafloor is used to identify areas of similar physical properties. Normalization was applied to the backscatter data to obtain acoustic response information which is independent from the incidence angle of the sonar beam. The mapped grey scale variation of the acoustic response is used to separate different types of seafloor. Four distinct types of seafloor have been depicted which are mounds, buried mounds, channel seafloor and inter channel areas. A semi-empirical method was applied to determine shape aspects of the angular backscatter strength. Three parameters, i.e. predicted 20° angular response, slope and coefficient of variation of the angular backscatter responses were computed to understand varying seafloor characteristics.The combination of backscatter and bathymetric data is another significant aspect of this contribution. Applying 3D visualisation techniques enables the user to link acoustic backscatter response to the seafloor morphology.