Euxinic systems can be defined by the underlying stratification of the upper oxygen rich region followed by anoxic and sulfidic conditions.  The relative dissemination and gradients of redox substances in these profiles helps to determine the major biogeochemical transformation processes (Nitrogen, Carbon, Sulfur cycling) that are mediated by microorganisms. A comparative study of these functional fingerprints  can reveal  the general functionality of these systems. It will also facilitates to distinguish commonalities and differences between different systems, which could also give insights into any latent global functionality of the oxygen depleted regions. Functional comparison of prokaryotic communities from these redoxclines of Baltic and Black Seas will be done using metatranscriptomics data available.