Floating seaweed as ephemeral neustonic habitat

• Main Author: Vandendriessche, Sofie
• Other Authors: Vincx, M
• Format: Doctoral or Postdoctoral Thesis
• Language: unknown
• Published: 2006
• Subjects: Sterna hirundo
• Online Access: https://biblio.ugent.be/publication/471152; http://hdl.handle.net/1854/LU-471152; http://doi.org/1854/6075; https://biblio.ugent.be/publication/471152/file/1878903

The results of this PhD thesis demonstrate that the habitat formed by floating seaweeds is very complex. Although the presence of floating seaweeds in the neuston can, to a certain degree, be seasonally predicted (storms, seasonal release of fertile structures), the habitat that they form is still very patchy and unstable. Consequently, most species found in association with ephemeral floating seaweed patches are opportunistic of nature. However, some species display a higher level of adaptation to this habitat than other species, which is manifested in the reproduction by continuous brooding in Idotea baltica, the diet consisting of seaweed-associated macrofauna in Cyclopterus lumpus and the behavioural shift towards surface pecking and dipping in Sterna hirundo. The association behaviour of the encountered species and their (optimal) use of the transient resources offered by floating seaweeds potentially have important ecological consequences, like for example the passive dispersal of associated fauna to new, distant locations by means of rafting. The process of rafting strongly depends on the longevity of the seaweed raft, which is in turn significantly influenced by temperature and grazing pressure. In favourable conditions, seaweed rafts can potentially cover great distances, carrying with them rafting fauna that are able to survive a long journey in the neuston.