Hydrochemistry and Production-Destruction Processes in the White Sea

The hydrochemical structure of the White Sea waters in both the pre-vegetation (winter) and summer periods is considered. The distribution of hydrochemical parameters, as affected by physical and biological factors, is shown for both the open deep sea and for the bays. The provision of phytoplankton with nutrients was estimated, and the primary production (PP) values and chlorophyll a content in the waters of the White Sea were measured. On average, phytoplankton synthesized about 1.1 g C/(m2 day). It was determined that the winter supply of nutrients provided about 7% of the annual PP, and the major portion of the PP was created by the vertical flow of nutrients from the underlying layers and the runoff from the rivers, as well as through the regeneration of nutrients during the oxidation of organic matter. The contribution of each of these factors to the annual PP was estimated to be ~33% and ~60%, respectively. Thus, in general, the share of new PP was about 40% of the annual PP. High chlorophyll a content, exceeding 1 μg/l, was observed throughout most of the sea. The obtained results indicate that the White Sea can be regarded as having eutrophic water.