Diversity of bacterial populations in the Beaufort Sea

Abstract

BIOLOGICAL communities usually contain few species with many individuals and many species with few individuals¹. Diversity of higher organisms generally has been found to decrease with increasing population size¹. Communities in physically stressed ecosystems, such as in polar regions, characteristically have low species diversity². Diversity indices have been used to express species diversity in plant and animal communities, especially as a measure of stress on community structure². Amongst microorganisms, diversity indices have been applied to microscopic phytoplankton populations^3,4, but not to bacterial populations. Bacterial populations, however, show large variations in species diversity. For example, infections are dominated by one or a few species, whereas many bacterial species are found in an ecosystem such as soil⁵. We report here the application of taxonomic diversity indices to bacterial populations and a study of the relationship of the diversity indices of such populations to population size and to population-independent factors such as geographic location.