An integrated open-coastal biogeochemistry, ecosystem and biodiversity observatory of the Eastern Mediterranean. The Cretan Sea component of POSEIDON system George Petihakis, Leonidas Perivoliotis, Gerasimos Korres, Dionysis Ballas, Constantin Frangoulis, Paris Pagonis, Manolis Ntoumas, Manos Pettas, Antonis Chalkiopoulos, Maria Sotiropoulou, Margarita Bekiari, Alkiviadis Kalampokis, Michalis Ravdas, Evi Bourma, Sylvia Christodoulaki, Anna Zacharioudaki, Dimitris Kassis, Emmanuel Potiris, George Triantafyllou, Kostas Tsiaras, Evangelia Krasakopoulou, Spyros Velanas, and Nikos Zisis Ocean Sci. Discuss., https//doi.org/10.5194/os-2018-3,2018 Manuscript under review for OS (discussion: open, 2 comments) Oceanic observations that examine several processes including biogeochemical ones are scarce. In the Eastern Mediterranean (Cretan Sea) the spatiotemporal coverage of such observations has increased with the expansion of the POSEIDON observatory. The observatory addresses scientific questions, provides services to policy-makers and society and serves as a technological test bed. It plays a key role in European and international observing programs, in harmonization procedures and data handling.