Patterns and dynamics of pelagic stream microbial community assembly
Hassell, Norman Henry
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The pelagic microbial communities of streams represent ideal populations to study community assembly along a natural continuum. We assessed multiple physiochemical and landuse parameters along the network, but the primary predictor of microbial community structure was the communities’ position relative to the stream continuum. Successional patterns were identified where taxonomic richness and compositional diversity decreased while the proportion of known freshwater taxa increased with increasing stream size. However, the observed trend was not present in two observation sets. In these samplings, streams exhibited uniformly high microbial diversity across the watershed, and the fraction of freshwater taxa showed no correlation to network position. Our work has revealed that these communities in streams exhibit a natural selection gradient under normal conditions but that this process is highly dynamic and can be disrupted, potentially in response to major environmental variation.