Linking geochemistry and geomicrobiology in selenium-contaminated soils

Dr. Carla Rosenfeld has been awarded an NSF Earth Sciences postdoctoral fellowship to carry out a research and education plan at the University of Minnesota, the Smithsonian Institution National Museum of Natural History, and the University of Maryland, College Park. For her research, Dr. Rosenfeld will combine microbiology and advanced analytical chemistry to understand the biological processes that influence selenium (Se) environmental impacts. Selenium contamination is a global problem, with many regions afflicted due to various anthropogenic activities. Microbial processes significantly influence Se mobility and bioavailability, and of particular interest are microorganisms that can remove excess Se from the food chain and water supplies. While microbial Se transformations in anaerobic environments have been more extensively studied, microbial interactions with Se in aerobic environments (i.e., the majority of soil environments that host plant and animal life) are not well understood. Clarifying what microorganisms are involved in Se biogeochemistry and how Se contamination influences and is influenced by microbial diversity in aerobic ecosystems is critical for understanding and predicting Se persistence and environmental impacts. In addition to studying microbiological influences on Se contamination, Dr. Rosenfeld will develop a hands-on, inquiry based geomicrobiology investigation at the Smithsonian National Museum of Natural History for museum visitors and K-12 classes. Additionally, Dr. Rosenfeld will mentor undergraduate and high school student researchers to develop and pursue their own research projects. <br/><br/>This research will dramatically improve our ability to address Se contamination by specifically linking Se in soils with microbial diversity and microbially mediated Se transformations in aerobic environments. Dr. Rosenfeld will collect soils from a Se-contaminated mine site as a function of distance from the plant root of three different plant-types (non-, primary- and secondary-Se-accumulators). Isolates of culturable Se-tolerant/transforming organisms will be identified and their relative abundance within the entire microbial community will be assessed. Culture-independent NextGen sequencing techniques will be used to analyze soil microbial community diversity as a function of distance from root surface, plant-type, and Se-content. Lastly, synchrotron radiation techniques will help to assess the connection between (micro)biological components and microscale Se chemistry as a function of plant-type.