Observation of developmental processes in loosely attached diatom (Bacillariophyceae) communities

Abstract

SUMMARY The succession of attached algal communities was studied in Lake Biwa and the Omiya River. After the ‘climax’ which was characterized by large numbers of Cymbella turgidula Grunow and Gomphoneis quadripunctatum (Ostrup) P. Dawson, the community was dominated by species attached directly to stalks or tangled among stalks. Stalks produced by species of the previous phase are important as secondary substrata. The dominant species of the new phase were ‘loosely attached species’, as defined by Hudon and Bourget (1983). I propose a new model consisting of phase 1, characterized by the first colonizers, including large rosette-type species and motile type species; phase 2, characterized by the stalk-producing species; and phase 3, characterized by the growth of loosely attached species.