Award: OCE-1739144

Archaea are single-celled organisms that are ubiquitous and abundant members of the marine plankton. Once thought of as rare organisms found in exotic extremes of temperature, pressure, or salinity, archaea are now known in nearly every marine environment. One group, the marine Thaumarchaotaa, was a focus for this project. Thaumarchaea are among the most abundant microbes in the oceans and catalyze the globally relevant process of ammonia oxidation. The goal of our project was to use unique cultures of thaumarchaea established by our laboratory to understand the ecology, evolution, and gene expression of this abundant group of microbes. We found that open ocean thaumarchaea have some of the smallest genomes of any free-living cell in the microbial world, and that they express nearly every protein encoded by their genome during growth. This information can be used for synthetic biology approaches that aim to construct a minimal cell. We also generated several additional high quality genomes for thaumarchaeal enrichment cultures from the open ocean through metagenomic sequencing, assembly, genome binning, genome closure, and subsequent annotation. Recruitment of metagenomics data from global expeditions show that these genomes are more representative of shallow open ocean populations of thaumarchaea, though it was also noted that different lineages are found in deeper waters. Controlled growth experiments with these enrichment cultures were combined with metatranscriptomes from marine ecosystems to compare gene expression in cultures and the lab. Results from this award were presented at numerous national and international meetings, and incorporated into graduate and undergraduate teaching modules at the University of Maryland and the University of California Santa Barbara. All data generated by the project have been made publically available through NSF's BCO-DMO database. The award trained two postdoctoral researchers, one graduate student, three technicians and multiple undergraduate researchers. Last Modified: 09/27/2018 Submitted by: Alyson E Santoro