The comparison of the years 1981/82 and 1984/85 on the background of long term climatic observations on Svalbard suggest that two seasons compared belong to extremely different ones with regard to the sea ice, air temperature and biological phenomena. Despite meteorological and hydrological differences, the phytoplankton bloom and breeding period of major crustaceans were placed in the same time of the year. Differences were noted in the structure of zooplankton community, abundance of sea birds and mammals.