Spatial and Seasonal Variability of the Chlorophyll a Concentration in the Barents Sea

Abstract

Variations in 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. The 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 the Chl-a concentrations were registered in spring and these decreased in summer and autumn. The summer season was the most productive period in Atlantic Water. The 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 the great significance of the indices associated with the global atmospheric circulation, mean annual temperature, and salinity anomalies, as well as the extent of ice in the Barents Sea.