2009 Volume 69 Issue 3 Pages 209-221
We compared the chlorophyll a concentration, taxonomic composition, and three-dimensional structure of periphyton communities developed in an artificial channel with and without deposits of biologically inert “silt” (silicon carbide particles). Algal community samples were collected 1, 3, 9-12 and 20-23 days after the start of the experiment, which was repeated six times. The presence or absence of “silt” deposits caused little differences in taxonomic composition or chlorophyll a concentration in pairwise comparisons, although significant differences in algal growth patterns were evident overtime. Chlorophyll a concentration, used as a proxy for algal biomass, often decreased between 9-12 and 20-23 days provided no “silt” deposits were present, whereas it always increased continuously provided “silt” deposits were present. The latter pattern might be explained by the relatively closed biofilm structure that results from the inclusion of “silt” particles since such a structure is probably more resistant to drag forces, and to being buoyed up by oxygen bubbles generated by algal photosynthesis, than a more open struchure without “silt” accumulations.
