Kurzzeitige Veränderungen hydrographischer Faktoren und der Sestonkomponenten in driftenden Wassermassen in der Helgoländer Bucht

Abstract

In Helgoland Bight (Inner German Bight, North Sea) drifting water masses were investigetad at 3 stations for 4-8 hours during August and November, 1968. Measurements of salinity, temperature, turbidity and seston weight were made and phytoplankton was counted in vertical series of water samples taken at about 30 - minute intervals. Only the water at drifting station "Außeneider" remained hydrographically unchanged during the investigation. The concentration of non-motile phytoplankton (diatoms) did not decrease with the slowing down of tidal current, whereas seston weight and turbidity decreased rapidly. Drift-cross tracking of the water at Helgoland Roads revealed that the water masses may circle around the island several times. Published results on horizontal diffusion and the present data indicate that measurements of changes within a plankton population over several days in Helgoland Bight require elaborate teamwork. © 1972 Biologischen Anstalt Helgoland.