Darian N Smercina
Linus Pauling Postdoctoral Fellow
Pacific Northwest National Lab
Evaluating Spatial and Molecular Drivers of Microbial Function
A grand challenge in soil microbial ecology is establishing the elusive link between microbial community structure and microbial function. This is particularly valuable as we attempt to understand and predict how microbial-driven ecosystem processes will respond in the face of climate change. As increasing evidence suggests that much of soil microbial function occurs in discrete hot spots and hot moments, it becomes clear that we need to view macro-ecological processes through the microbial lens. My work aims to characterize the microbial worldview, establishing the effective size of a microorganisms habitat in soils and relating this to our ability to detect and predict key ecosystem processes. My work uses biological nitrogen fixation, a ubiquitous and important terrestrial process, as a model ecosystem process to study how micro-scale processes and interactions between microorganisms and their environment drive the observed community structure and function we measure at a macro-scale. The results of this work have the potential to improve data collection on soil microbial communities and predictive modeling of soil-based ecosystem processes.
In situ Characterization of Associations and Resource Exchange Between Free-living Nitrogen-Fixers and Switchgrass
While it is becoming increasingly clear that many plants, including switchgrass, associate with active diazotroph communities, the mechanisms driving these interactions including if and how carbon (C) and nitrogen (N) are exchanged is not known. My DOE SCGSR fellowship project at EMSL, In collaboration with many great people at EMSL including (but not limited to) Kirsten Hofmockel, David Hoyt, John Cliff, and Will Chrisler, I am using several of EMSL's state-of-the-art techniques to take a finer scale look at interactions between switchgrass and diazotrophs in order to address the "carbon for nitrogen" exchange hypothesis. Combining fluorescent in situ hybridization, NanoSIMS, and metabolomics, we hope to provide a novel, mechanistic perspective of carbon and nitrogen exchange - addressing if and how plants, like switchgrass, exchange fixed carbon for diazotroph fixed nitrogen. Check back soon for project updates!