Currently Funded Research Projects
Characterizing the contribution of bacteria from the SUP05 clade to autotrophic and heterotrophic carbon cycling across ocean gradients
The balance between autotrophy and heterotrophy in the ocean is a key ecosystem parameter that determines the size of the ocean’s carbon sink and the food available to higher organisms. Currently, the outcome of competition for released nutrients between autotrophs and heterotrophs is unknown, leaving a critical gap in our ability to quantify the balance between these processes. Here we propose to study a metabolically diverse group of bacteria that contribute to both autotrophy and heterotrophy (SUP05) and that are inspiring great interest due to their roles in elemental cycling in the dark ocean and in suboxic and anoxic zones, the latter of which are ecosystems that are expanding due to global climate change. This research will elucidate the autotrophic and heterotrophic roles of this important group of marine bacteria in global nutrient cycles by characterizing their responses to present and future environmental conditions.
Previously Funded Research Projects
Mechanisms of carbon assimilation and sulfur oxidation in the genus Thioglobus
We now have in pure culture the only known isolates from an important group of marine sulfur oxidizers and are adressing fundamental questions about their roles in carbon and sulfur cycling. Our data indicate that they use energy derived from aerobic sulfur oxidation to assimilate carbon. This suggests that sulfur oxidation enhances carbon turnover in the oxygenated ocean. We will continue to elucidate the important roles of this ubiquitous and abundant group of organisms in marine carbon and sulfur cycles.
Characterizing biological function across a persistent oceanographic "hotspot"
Here we use post-genomic approaches to probe the activities of cells across an ocean boundary that extends into a high nutrient low chlorophyll (HNLC) region in the North Pacific. We use metagenome and metatrascriptome, protein expression, metabolite profiles and cell-specific metal quotas to identify feedbacks and functional linkages between biological communities and their geochemical surroundings.
Proteomics Directed Environmental Genomics
Here we used proteomic approaches to identify the in situ functions of bacterial communities in the South Atlantic Ocean. We identified shifts in bacterial nutrient utilization and energy transduction accross the South Atlantic and resolved unique patterns in community structure along basin-scale gradients in nutrients, chlorophyll, and dissolved organic carbon (Morris et al., 2010, Morris et al., 2012).