The Black Sea is the largest anoxic basin on earth and provides unique conditions for the study of key processes controlling the biology and biogeochemistry at pelagic redoxclines. By identifying microbiological/biogeochemical agents and assessing rates of the coupled element cycles of carbon, nitrogen, phosphorus, sulphur, manganese, and iron, the functional response of this specific environment to changes of external conditions will be visible. This entry summarizes the CTD and pump-CTD data collected during the MSM33 cruise to the Black Sea in 2013. The data set contains both the bottle files, documenting bottle ids and metadata, as well as the CTD profiles. The following parameters were measured: temperature, salinity, conductivity, turbidity, chlorophyll a, pH, redox potential, oxygen, sound.