Mobile epifauna onZostera marina,and infauna of its inflorescences

The faunal colonization of the leaves and inflorescences of intertidalZostera marina L. and of the ambient water has been studied at the Island of Sylt (North Sea). The abundance of the snailLittorina littorea L. and the isopodJaera albifrons Leach correlates significantly with leaf surface area. This is not the case with the abundance of meiofaunal Plathelminthes, Nematoda, Copepoda, and Polychaeta. However, they increase significantly with the numbers of generative shoots in the sampled seagrass bunches. Members of these taxa inhabit theZostera inflorescences, and average abundance increases with the degree of decay of inflorescences. This temporary microhabitat presumably offers food and shelter. Copepods and ostracods dominate in the ambient water. Planktonic calanoid copepods correlate with the amount of sampled seawater, while Ostracoda correlate with the amount of resuspended detritus suggesting that they were resuspended themselves. The study shows that some meiofaunal taxa can rapidly exploit a short-lived habitat such as theZostera inflorescences. Juvenile polychaetes use inflorescences as a nursery.