The effect of varying oxygen conditions on benthic microbial communities was investigated at the North Western Crimean shelf break (Black Sea), at water depths between 105-207 m. Sampling was performed with a TV-MUC on April-May 2010 on board of the RV Maria S. Merian (Cruise MSM 15-a) along gradient of oxygen bottom water concentrations between oxic (150 µmol L-1, station 464), variable hypoxic (3-60 µmol L-1 O2, stations 487 and 393) and anoxic, sulfidic conditions (station 448).