Substratum location and zoospore behaviour in the fouling alga Enteromorpha

The green alga Enteromorpha is the most important macroalga that fouls ships, submarines and underwater structures. Major factors in its success in colonising new substrata are the production of enormous numbers of swimming spores;and their ability to locate surfaces on which to settle. Factors facilitating the settlement and adhesion of asexual zoospores are examined in this article. Settlement and adhesion may be regulated by topographical, biological, chemical and physico-chemical cues, all of which are modified by the presence of microbial biofilm. The level of gregarious zoospore settlement is related to spore density and may be mediated by a number of external cues including fatty acids and 'detritus'.