Phytoplankton and the physical environment in the Helgoland region

Abstract

The phytoplankton development in the waters around Helgoland can be described as a function of the physical environment (derivates of the temperature). This is a consequence of the fundamental annual cycle regulated by the sun and, respectively, by dependent components. This simple statement can only give good results if the turbulent transport processes in the transition zone are considered. Investigations are impeded by the fact that the multiplication rate of the organisms is almost counterbalanced by losses that take place during the long lasting bloom. This situation is a product of the regional hydrography, whereby small changes in the environment on varied time scales influence the development of the population fundamentally. This becomes particularly clear when the numerical results of the exponential growth are examined. The dynamics of this complicated process can be seen best in the great annual differences of the phytoplankton maxima.