Temporal and spatial changes in the bio-optical properties of seawater in the Nordic Seas – AREX’2003 and 2006

For many years the Nordic Seas have been the subject of research into ocean circulation carried out by the Institute of Oceanology PAS, especially the inflow of Atlantic water and the intensive turbulent mixing of these waters with Arctic and shelf waters. Ocean currents affect various biological processes, among them the supply of organic matter and oxygen, which constitute the foundation for the unique flora and fauna of the Svalbard islands. Spectrophotometric examinations of surface waters using an M32 B spectroflu- orophotometer (LDI Ltd.) were carried out repeatedly during Arctic cruises on board r/v ‘Oceania’. The results presented in this paper come from the AREX campaigns of 2003 and 2006. Analysis of the chlorophyll a fluorescence excitation spectra recorded shows an increase in phytoplankton abundance and the changes in the spatial distribution of the phytoplankton species characteristic of Atlantic, Arctic and shelf waters. The spatial patterns of the phytoplankton pigments and their abundance were compared with the physical characteristics of water masses. The analysis confirmed that phytoplankton species move together with the Atlantic water as this flows into northern latitudes.