Structural characteristics of algal communities in thermally altered artificial streams

Abstract

Algal community structure on natural substrates of thermally altered artificial streams was studied for one year. The streams were fed by a natural blackwater stream near Aiken, South Carolina. Temperature-related shifts in the abundance of major species were demonstrated. Red algae were absent from a stream heated 12.5°C above ambient, but remained abundant in streams heated 7.5 0 C or less. Water temperatures above 30°C produced blue-green algal dominance and eliminated several indigenous species. Substrate specificity was exhibited by all major taxa. Several taxa were abundant only on the bottom sediments and some showed a distinct affinity for either sand or silt, the principal bottom types.

Temperature and nutrient supply interact to control nitrogen fixation in oligotrophic streams: An experimental examination

“…dominated at temperatures higher than 30uC, and when experimental temperatures were decreased by 12.5uC, Schizothrix sp. were replaced by a yellow-green algae within 2 months (Wilde 1982). Collectively, these studies indicate that temperature could control N 2 fixation in streams at the community level.…”

“…Cairns (1956) demonstrated that algal communities from a nonpolluted temperate stream shifted from dominance by diatoms at 20uC, to green algae between 30uC and 35uC, and finally to cyanobacteria at temperatures above 35uC. In experimental streams, Wilde and Tilly (1981) found that the cyanobacteria Schizothrix sp. dominated at temperatures higher than 30uC, and when experimental temperatures were decreased by 12.5uC, Schizothrix sp.…”

Responses of attached algal communities to termination of thermal pollution

“…1). This facility has been previously described by Harvey (1973) and Wilde & Tilly (1981). A thermal phase of FSL operation began in March 1976 and was continued until February 1979.…”

“…One portion was left intact, while all rocks in the other portion were removed and replaced with similar shaped rocks which had been collected from the parent stream, cleaned, and sterilized. Collection and microscopical techniques for examining red algae were as previously described by Wilde & Tilly (1981).…”

“…A recent study (Wilde & Tilly 1981) described thermally induced structural alterations of attached algal communities in an outdoor laboratory system containing six artificial streams. Results showed:…”