Circadiel patterns in the tidal plankton of a sandy beach in Zeebrugge (Belgium)

The intertidal fauna of a Belgian sandy beach was sampled on an hourly basi s with a hand-pushed sledge to study circadiel patterns in species composit ion. Four assemblages could be distinguished with classification and ordina tion techniques. A first division separated the samples taken during daytim e from the night samples. Both assemblages were subsequently divided into a n ebbtide and a floodtide situation. Light intensity and tidal height were the most important variables explaining the variation in the Canonical Corr espondence Analysis.