Interannual Variability of the Ice Cover and Primary Production of the Kara Sea

Abstract

Model and satellite data have been used to analyze interannual changes in the primary production (PP), ice-free area, and water temperature in the Kara Sea between 2002 and 2016. Significant positive trends for changes in the surface water temperature were recorded for all regions of the Kara Sea (R2 = 0.37–0.61, p < 0.05). A reliable trend toward an increase in ice-free surface area was observed only for the Yenisei estuary. PP growth trends were significant in the northern Region of the sea and the Yenisei estuary. The decrease in ice cover area for the entire Kara Sea amounted to 1% per year. A PP minimum was recorded in 2003, and a maximum, in 2011. The average increase in Kara Sea PP during the study period was 2% per year. The most rapid increase in Kara Sea PP was observed during the spring season (April–May). The increase in annual PP was mostly due to the expansion of the ice-free area. The increase in the phytoplankton photosynthesis rate could not have resulted in the increase in PP, because the average photosynthesis rate for the entire sea decreased during the study period. Considerable region-specific variation in the patterns of interannual Changes in PP in the Kara Sea were observed.