HR: 13:45h
AN: NB33U-02 INVITED     [Abstracts]
TI: Twenty-eight Days to a Climax community: A Succession Laboratory Using Periphyton
AU: * DeNicola, D M
EM: dean.denicola@sru.edu
AF: Department of Biology, Slippery Rock University, Slippery Rock, PA 16057 United States
AB: Succession in benthic algal communities (periphyton) occurs in a relatively short time scale because of the rapid reproductive rates of algae. To examine primary succession of periphyton in a lake and stream, unglazed tiles are placed in the respective habitats and sampled on days 4, 8, 16 and 28. Students count the preserved samples at 400X and identify taxa to genera based on customized picture keys (does not require a high degree of instructor expertise). Genera also are categorized according to algal growth forms, based on the size, shape, motility and attachment mechanism. After pooling the class data, students present the change in community structure, contrast succession between the lake and stream, and hypothesize which mechanisms may apply (facilitation, inhibition, tolerance). Successional sequences also are examined to see whether they agree with published growth form models for periphyton succession in lotic and lentic habitats. The laboratory uses the more intuitive method of repeated measures to study succession as an alternative to the often infeasible chronosequence method traditionally done for terrestrial communities. Additional outcomes include, reinforcement of the concept of species guilds (growth forms), an introduction into the use of empirical models, and an increased awareness of microorganism communities.
DE: 0805 Elementary and secondary education
DE: 0810 Post-secondary education
DE: 0825 Teaching methods
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly