Spatial and seasonal variability of chlorophyll A concentration in the Barents Sea

Variations of the surface chlorophyll a concentration (Chl-a) measured during 25 cruises conducted from 1984 to 2020 were investigated in the Barents Sea and adjacent Svalbard waters. Seasonal maps of the mean annual Chl-a estimations were created for the Barents Sea. Significant seasonal and temporal variations of Chl-a were found in different water masses. Surface Chl-a content reached a maximum in the spring (46% of the annual estimation). In the summer, it tended to decrease accounting for 28% of the total annual value while in the autumn and winter Chl-a was found to be 21% and 5% of the total annual stock, respectively. Atlantic Water and Arctic Water had the highest contribution to the total annual Chl-a biomass. In Arctic Water, peaks of Chl-a concentrations were registered in spring and these decreased in summer and autumn. Summer season was the most productive period in Atlantic Water. Chl-a dynamics and distribution in relation to climatic factors were investigated. Application of generalized linear and non-linear models to predict Chl-a variations showed high significance of the indices associated with global atmospheric circulation, mean annual temperature and salinity anomalies as well as ice extent in the Barents Sea.