Authors: Amanda Lee, Alex Phillips, Bonnie Baxter, Amy Schmid
Mentors: Bonnie Baxter
Insitution: Westminster College
The Great Salt Lake is home to a massive variety of microorganisms and insights into these populations will aid in understanding the ecosystem. The Union Pacific Railroad’s causeway has divided the lake into two distinct sections and over time caused the North Arm to increase in salinity over the South Arm and gain its hallmark pink color due to restricted freshwater input. Terminal rivers flow into the South Arm while the North Arm’s water evaporates, leaving behind accumulating salty brine, and the two very different waters have nurtured two accordingly distinctive ecosystems. Breaches periodically opened in the causeway allow the waters to mix and provide opportunity for the microbial communities of the two arms to intermingle. In a collaboration between the Great Salt Lake Institute at Westminster University and the Schmid Lab at Duke University, this project focuses on procuring a picture of the North Arm’s microbial diversity and the extent that it adapts to new environments over the four seasons, as well as what happens to the microbes and their nutrient exchange at that breach mixing point. Halophilic archaea and algae comprise the majority of biodiversity in the lake, and we hypothesize that those taxonomic compositions of the North Arm are stable over the different seasons, due to their extremophilic nature. Every season, we have collected water samples from the causeway, breach, and Spiral Jetty to grow and isolate bacterial colonies for DNA extraction and imaging. We also collect biofilm on filters to analyze RNA gene expression and metabolite usage as the environment changes. Over nearly two years of sampling, the hypothesis has been supported and we are seeing stability in community compositions in comparison to the less-salty South Arm. We are still interpreting results from the mixed breach samples, but thus far the microbes appear to be similar to those in the North Arm.