Remotely sensed studies of phytoplankton dynamics under physical forcing in different ocean regions

The information obtained from the modern Earth-observing satellites, enables comprehensive studies of seasonal dynamics of ecosystems in different regions of the World Ocean. The properties of physical environment (sea surface temperature, measured by AVHRR radiometers; currents estimated from altimetry data; wind and precipitation measured by meteorological satellites) combined with biological data derived from ocean optics, reveal principle features of phytoplankton seasonal cycles in diverse ocean environments. The peculiarities of these cycles depend on local bottom topography, hydrological regime, wind forcing, etc; in coastal regions river discharge is of great importance. The examples of different types of seasonal cycles of phytoplankton are presented, and the mechanisms influencing the phytoplankton growth are discussed. The peculiar region is the Northwest Atlantic near Newfoundland Rise, where abrupt environmental contrasts (the cold Labrador Current flowing from the north and the warm Gulf Stream from the southwest) result in different types of seasonal cycles over rather narrow area. Another illustrative example is the Black Sea where extremely high water stratification results in a seasonal cycle similar to subtropical regions rather than to temperate ones. The general patterns of seasonal phytoplankton cycles depend on physical factors influencing water stratification.