Seasonal and interannual variations of surface chlorophyll concentration in the Black Sea on CSCZ data

Both seasonal and interannual variations of surface plant pigment concentration measured by CSCZ radiometer in 1978-86 are analyzed in different regions of the Black Sea. The regular seasonal variations agree well with the data from the field observations. 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 slightly lower level of pigment concentration during warm season are typical for years with 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 of hydrological mechanism (i. e. the intensity of water mixing during winter period due to thermal convection and wind mixing) rather than the illumination intensity.