The majority of microbial diversity on the planet resides in cryptic lineages of Bacteria and Archaea that have no cultivated representatives. Many of these microbial groups are ancient and have had a profound influence in shaping the chemical environment of Earth, yet their ecology and evolutionary history often remains obscure. For this research we use an evolutionary genomic approach to analyze the phylogenetic relationships within and between uncultivated microbial groups in order to discern the environmental factors have shaped their genomic repertoires.
Evolutionary genomics of uncultivated microbial groups
Understanding the dynamics of microbial community ecology and metabolism is often complicated by difficulties in pinpointing the appropriate scale to analyze the processes of interest. Marine microbial communities inhabiting the surface waters of the ocean are a useful system for understanding these dynamics since diel cycles are known to be important aspects of the physiology of many marine microbes. This research coupled high-throughput transcriptomic sequencing together with high-temporal resolution sampling of marine microbial communities to investigate ecological and metabolic dynamics over daily timescales. A prominent finding of this work is the apparent coordination between photoautotrophic and heterotrophic community members which underscores important ecological dynamics underpinning carbon and nutrient transformations in these systems.