Benthic Algal Community Dynamics in a Stream during and after a Spate

Publisher Website
Google Scholar
Abstract
Changes in a benthic algal community were observed during and after a major storm. Algal abundance, mostly diamtoms, increased slightly during a 3-d interval that included the storm on day 1. Positive effects of the storm on benthic algae were indicated by decreases in the proportions of diatomes that were dead, but not in the dead cell numbers, and by decreases in the proportions of sexually reproducing cells. Increases in current or nutrient supply to periphyton during the storm may have stimulated growth of live cells and retarded sexual reproduction. During two 3-d growth periods after the storm, benthic diatoms grew rapidly from 1.1 .times. 107 cells/cm2 and seemed to reach a carrying capacity near 5.2 .times. 107 cells/cm2 in only 8 days. Density-dependent decreses in growth rates were accompanied by increases in the proportion of diatoms that were dead or in stages of sexual reproduction, indicating nutrient limitation. Immigration was not an important mechanism of accumulation immediately after the storm. However, immigration/colonization rates increased during community development and indicated substantial turnover by cell transport during late succession. Benthic diatom communites are well adapted to storms in temperate climates in streams with gravelbed channel morphology. I hypothesize that benthic diatoms are actually affected positively by most storms and are negatively affected only by the most severe storms that overturn substrates in the stream.

This publication has 0 references indexed in Scilit: