The Structure of a Geothermal Stream Community

Abstract

Studies of changes in the community structure of a geothermal algal/bacterial community were carried out utilizing electron microscopy as an analytical device. Stereological techniques were used to obtain quantitative information from micrographs of algal mats. This resulted in the description of the mat community in terms of its biomass, organism distribution indices, organism density, and operational taxonomic unit diversity. An important feature of analyzing microcommunities in this way is that the spatial integrity of the organisms within the community is retained while considerable quantitative information is acquired. The submerged community, consisting of cylindrical strands (ca. 90 mm long) growing in a fast-flowing, hot-water stream (54 C) from Mimbres, New Mexico, contained primarily blue-green algae (cyanobacteria), bacteria, and amoebae embedded in a gelatinous matrix. Blue-green algae were distributed throughout the entire community but were more concentrated at the periphery. The central por...