Rhizon soil moisture samplers were successfully used for multi-level pore water sampling from in-situ sediments and sediment cores. By this method, high resolution pore water profiles may be sampled with minimum disturbance of both, the sediment structure and possible flow fields. To investigate biogeochemical cycles, especially at the sediment/water interface, we present a newly developed Rhizon In Situ Sampler (RISS) as a non-destructive tool for in-situ pore water sampling. Field experiments, tracer studies and numerical modeling were combined to assess the suitability of Rhizons for pore water sampling. A combination of a benthic chamber with the RISS allows studies of benthic fluxes and pore water profiles at the exact same location with negligible effect on the incubated sediment/water interface. This allows improved modeling of transport and reaction processes. Long term deployments of the RISS and repetitive pore water sampling will support future studies of the seasonal variation of benthic processes.