UC Irvine

Microbial communities are hard to study, yet their importance is hard to overstate. They inhabit every surface on Earth and are core participants in global biogeochemical cycling, but this is under threat due to anthropogenic climate change.One important microbiome is those communities that can be found decomposing leaf litter, the top layer of soil. This decomposition is critical for recycling nutrients back into the soil for the next generation of life. Here, I made use of microbial “cages” that permit water and nutrients to flow in and out while preventing microbial dispersal, allowing the study of microbes in situ. With the help of amplicon, metagenomic, and whole genome sequencing, and from the perspectives of ecology, evolution, and physiology, I dove into a single bacterial genus, Curtobacterium, to investigate the amount of ecologically important variation from closely related strains. I found evidence of variation between clades, with some strains surviving 10x better under desiccation than others. Further, variation exists between subclades, that might be missed using well-established methods of community analysis. I also investigated within a subclade, finding evidence that evolutionary processes operate during the timescale of ecological processes.