Molecular analyses of microbial mats
Date
2018
Authors
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Publisher
University of Delaware
Abstract
Whether found in shallow water sediments or at the bottom of the deep-sea, microbial mats are key participants in the recycling and utilization of important elements and compounds. Despite these mats being nearly ubiquitous, little research has focused on the early stages of their community assemblage. In chapter 1, I describe the development of microbial mats on two bones exposed to water incoming from a tidal river. Molecular analysis of these mats, including 16S rRNA gene amplicon and metagenomic sequencing, showed that gammaproteobacterial classes aided in the initial development of the mat, and were swiftly overtaken by epsilonproteobacterial classes. This observed successional change in mat members over time was not represented in the putative functions associated with the communities, as the potential for autotrophic and heterotrophic lifestyles overlapped throughout the duration of the mat development. Together these data suggest that functional redundancy may be a characteristic of these mat types, despite the shifts in mat community members. I wanted to further understand the phylogenetic and functional potential of one mat member in particular, the large filamentous sulfur-oxidizing Beggiatoa. Nine metagenomic bins were retrieved from the mat metagenomes and compared with marine and freshwater genomes. Beggiatoa genomes from shallow waters and their deep water counterparts appear to rely on different modes of growth and energy acquisition. Furthermore, pangenomic investigation suggests that shallow-dwelling Beggiatoa may be more suited to regulate their responses to stimuli such as light changes, and that the gene history of these organisms may shift due to different habitats or geographic location.