The relevance of ecophysiology in astrobiology and planetary research : implications for the characterization of the habitability of planets and biosignatures Eco physiological processes are expressing the interaction of organisms within an environmental context of their habitat and their degree of adaptation level of resistance as well as the limits of life in a changing environment. The present study focuses on observations achieved by methods used in this scientific discipline of “Ecophysiology” and to enlarge the scientific context in a broader range of understanding with universal character. The present eco physiological work is building the basis for classifying and exploring the degree of habitability of another planet like Mars by a bio driven experimentally approach. It offers also new ways of identifying key molecules which are playing a specific role in physiological processes of tested organisms to serve as well as potential biosignatures in future space exploration missions with the goal to search for life. This has important implications for the new emerging scientific field of Astrobiology. Astrobiology addresses the study of the origin evolution distribution and future of life in the universe. [...]