The first “organized” and regular biological observations at the time series station C1 in the Gulf of Trieste, North Adriatic Sea, date back to the early 1970s and were initiated by the University of Trieste. A regular monthly sampling for hydrological, chemical as well as biological (phytoplankton and zooplankton in several size classes) analysis began later, in 1986. The time series station C1, initiated by the University of Trieste, was later taken care by the Laboratory of Marine Biology of Trieste after its formal institution in December 1979 and, since October 2005, by the Department of Biological Oceanography, now Division of Oceanography (OCE) of OGS, Istituto Nazionale di Oceanografia e Geofisica Sperimentale of Trieste.