The Mississippi River (MSR) is the 4th longest and 10th largest river in the world, with a watershed draining 31 U.S. states and 2 Canadian provinces. As a result of this considerable geographic range, the MSR is also subject to substantial human influences from agriculture, municipalities, damming, diversions, and recreation. These inputs affect not only the river itself, but also the Gulf of Mexico, where the MSR can deposit hundreds of thousands to millions of cubic feet of water per second. Thus, there is great importance for understanding how nutrient and pollutant inputs to the river are processed, and how that impacts the underlying microbial communities. However, because of its size, sampling the MSR is both costly and difficult. To combat this, our lab teamed up with OAR Northwest, a non-profit educational and exploratory group, to use human powered rowboats to sample a nearly complete (>1800 mi) transect of the MSR. Analysis of the data has utilized both next generation amplicon sequencing to generate over 13 million reads from 152 samples from 38 sites as well as accompanying environmental parameters for each site. The shear size of this project has led us to incorporate both traditional ecological analyses as well as newer approaches such as Weighted Gene Co-Expression Network Analysis (WGCNA) to help elucidate the role of nitrate and phosphate in the separation of the microbial community within the upper and lower MSR.
Born and raised in the Midwest, I came to Louisiana State University and to Dr. Cameron Thrash’s lab from Dr. Deric Learman’s lab at Central Michigan University where I completed my MS thesis investigating the genomic, physiological, and chromate reduction variation among four Microbacterium isolates. Here at LSU, my research within the Thrash lab focuses on understanding how biogeochemistry influences the biogeography and community structure of microorganisms in the environment using both cultivation and cultivation-independent techniques. The two main projects have concentrated on important aquatic ecosystems to the Louisiana community: the Mississippi River and coastal northern Gulf of Mexico. These projects have challenged us to reconsider how to approach the issues of cultivating the unculturable, analyzing “big data”, and intertwining genomic and community data with environmental parameters by utilizing new and repurposed techniques.