CHARACTERIZING THE STRUCTURE OF BACTERIAL COMMUNITIES

Two types of characteristics can be used to describe the structure of a microbial community considered at the level of the entire biogeoceno sis. The first is a group of stock or average indicators, such as mean density of microorganisms in different substrates, list of all taxa i nvolved, and alpha-diversity. The second is a group of differentiating characteristics reflecting the spatial and syntypological structure o f the community: the type of distribution over strata, spectrum of pot ential dominants, beta-diversity, and relationship between ecological groups. Using the group of saprotrophic bacteria in two widely differe nt habitats, deserts and swamps, as an example, averaged measures were found to be more conservative, and differentiating characteristics, m ore changeable and able to portray more accurately the specific proper ties of different microbial communities.