Algal Colonization on Rocky Shores in the Firth of Clyde

Publisher Website
Google Scholar
Abstract
The algal colonization of rocky shores in the Firth of Clyde, Scotland, UK, was investigated by both observations and experiments in nature, and by culture experiments in the laboratory. The species whose propagules were most abundant in the water were also the commonest colonists of glass slides exposed on the shore, and patchiness in the distribution of the propagules in the water was reflected on the slides. Both the species diversity of the colonists and the abundance of individual species were greater beneath a canopy of Ascophyllum nodosum than in uncovered sites, and at 2.49 m above Lowest Astronomical Tide level as compared with 2.89 m. Irrespective of the inoculum of propagules available, only species that normally inhabit the upper littoral zone successfully colonized slides exposed at that level. Culture experiments in a simulated tidal regime revealed other factors that might influence algal settlement and development. For example, a period of unstressed conditions immediately following settlement increased the degree of aerial exposure tolerated by young plants. High settlement densities enhanced this effect. A thick turf of adult Enteromorpha intestinalis plants acted as a barrier, significantly reducing the number of spores of Ulothrix pseudoflacca reaching the substratum beneath. Conversely, it also enabled spores already established beneath the turf to withstand longer exposures to air than those unprotected by a moisture-retaining canopy.

This publication has 4 references indexed in Scilit: