Patterns of Seasonal and Interannual Changes of Surface Chlorophyll Concentration in the Black Sea Revealed from the Remote Sensed Data

Abstract

Several years of CZCS-measured surface pigment’s concentrations in the Black Sea are analyzed to appraise the seasonal and year-to-year fluctuations of phytoplankton biomass and understand the causes of these fluctuations in terms of the Black Sea’s general dynamics. The pattern of seasonal variations is typical for subtropical rather than temperate regions. The range of the absolute value of plant pigment surface concentration measured by remote sensing does not differ greatly from the values measured by direct methods. The pattern of year-to-year variations seems to correlate with cyclic oscillations of winter air temperature. In western shallow regions it is also correlated with the Danube discharge intensity. More intensive winter–spring blooms and a slightly lower level of pigment concentration during warm season are typical for years of with a mild winter. The causes of these regularities seem to be the peculiarities of hydrological and meteorological regimes of the Black Sea. The intensity of winter–spring bloom of phytoplankton appears to depend on hydrological mechanism (i.e., the intensity of water mixing during winter period due to thermic convection and wind mixing) rather than the illumination intensity.