Settlement experiments with zoospores ofEnteromorpha intestinalis(L.) link

Abstract

A method for obtaining uniform settlement of zoospores of Enteromorpha intestinalis is described. Using this method the optimum temperature for settlement on glass lies between 20 and 25 ° C, and the optimum salinity between 25 and 30°/°°. Light exerts a considerable influence on the initial rate of settlement but is not essential.

The settlement, attachment and establishment of marine algal spores

“…However, there is evidence from laboratory based experimental studies that algae do preferentially settle on roughened surfaces. This has been demonstrated for example, for the motile spores of the brown algae Ectocarpus (Miiller, 1964;Russell & Morris, 1971;Clitheroe & Evans, 1975) and Chorda filum (South & Burrows, 1967) and the green alga Enteromorpha (Christie & Shaw, 1968;Christie, 1973). This ability to detect surface profiles was reported by Christie (1973) (Subbaramaiah, 1970) and Ectocarpus (Baker, 1971), whilst Linskens (1966) (Linskens, 1966).…”

“…Probably the most widely reported taxis in algae is phototaxis in which the motile stages of algae can apparently detect and respond to variations in light intensity. It has been widely reported for the motile spores of green and brown algae (Smith, 1947;Christie & Shaw, 1968;Moss & Woodhead, 1970;Baker & Evans, 1973a;Christie, 1973) and appears to be related to the settlement process. For example, whilst gametes are generally positively phototactic keeping them suspended in the water column and increasing their chances of gametic union, zoospores and fused gametes are generally negatively phototactic or swim towards areas of low light intensity, increasing their chances of settlement.…”

“…up to, and for at least, 24 h in Ectocarpus (Baker, 1971) and Laminariales (Henry & Cole, 1982) respectively, 8 days in gametes of Enteromorpha (Jones & Babb, 1968). The period of motility appears to be determined by environmental conditions such as temperature and salinity (Christie & Shaw, 1968;Jones & Babb, 1968;Christie, 1973) which will likewise determine the ability of spores to settle (Christie & Shaw, 1968;Christie, 1973). It is unlikely, however, that spore motility plays a major role in the location of the substratum except in very close proximity to the surface and under conditions of very reduced water movement (Chamberlain, 1976).…”

“…As suggested above, the flagella of motile spores play an important role in the settlement process, assisting in the passage of the spore to the boundary surface layer and through variously described spinning and vibratory actions (South & Burrows, 1967;Christie & Shaw, 1968;Toth, 1976a;Fletcher & Peters, 1981) undertaking a degree of site selection by the probing activity of their flagella (Amsler & Neushul, 1989; and then positioning the spore correctly in relation to the substratum (e.g. anterior end down in Enteromorpha (Evans & Christie, 1970;Christie & Shaw, 1968;Gunn et al, 1984), Chareium (Lee & Bold, 1974) and Chorda filum (South & Burrows, 1967).…”

Foam as a dispersal agent in the rocky intertidal of central Chile

“…This viability involves the attachment ability of the spore, which differs among species of benthic algae. For example, Enteromorpha seems capable of attachment for several hours (Christie & Shaw, 1968;Christie et al, I970), while Sargassum muticum propagules retain their ability to attach unchanged for 18 days (Deysher & Norton,I982). Seafoam could provide the wet environment necessary for the spore to obtain access to the substrate while it retains an ability to attach.…”