Tvärminne Zoological Station and its sister stations Lammi Biological Station and Kilpisjärvi Biological Station belong to the Faculty of Biological and Environmental Sciences, University of Helsinki. TZS is a marine station located at the entrance to the Gulf of Finland. It serves as a centre for a large variety of high quality biological research, carries out environmental monitoring, and offers facilities for field courses and seminars.
TZS has an over a century long history of scientific research, with emphasis on the brackish waters of the Gulf of Finland. The station was established in 1902 and thus provides good background data for studying long-term environmental change. In addition, it is situated in a nature reserve, where only research and teaching activities are allowed.