This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). Intensification of hydrologic regimes due to climate change will have important impacts on biogeochemical processes and ecosystem services, but quantifying these impacts experimentally remains a key challenge for earth scientists. My research goal is to investigate the potential impacts of increased precipitation on the interrelationship between biogeochemical cycling of iron and organic matter. In pursuit of this goal, the objectives of this CAREER proposal are to: 1) determine the impact of increasing water content on the iron mineralogy and chemical structure of humic substances along subalpine moisture gradients, 2) Elucidate the role of chemical structure and concentration of humic substances on iron biomineralization along these moisture gradients and in detailed laboratory studies, and 3) Reveal the influence of aqueous geochemistry on the spatial distribution and macromolecular structure of humic substances at the mineral?water interface. The research approach is integrative and will investigate biogeochemical transformations of iron minerals, humic substance structures, and iron organic matter interactions along subalpine moisture gradients at the USDA FS Fraser Experimental Forest in Colorado. In addition, well-characterized iron minerals will be inserted into the soil at multiple depths along the moisture transects to provide more information about the impact of moisture on iron biomineralization pathways under natural conditions. Microbial iron reduction and the spatial distribution, macromolecular structure and chemical composition of humic substances at the iron-water interface will be studied for the first time at the nanometer-scale by scanning transmission X-ray microscopy. My long-term educational goals are to: 1) educate and train future scientists with a tool box of analytical and problem solving skills to address the most complex challenges in environmental biogeochemistry, and 2) to get more woman and minorities interested in the field of Earth sciences. In pursuit of these goals, the objectives of this CAREER proposal are to: 1) Integrate today's Environmental Biogeochemistry topics into the environmental science curriculum in a real time format, and 2) Launch MEB (Mentoring Environmental Biogeochemistry): an undergraduate research program that brings together multi-disciplinary participants to increase diversity in environmental science and enhance the pipeline for graduate studies. The educational approach is to develop a set of new courses that integrate the need for responsive environmental biogeochemistry topics in the environmental science curriculum and that will be evaluated and assessed professionally. Inquiry-based learning and peer-learning with a laboratory component will be especially valuable for training of scientists in an interdisciplinary field. MEB activities will also specifically address the need for representation of woman and minorities by focusing on topics that have demonstrated to attract underrepresented groups. Intellectual Merit: It is important that we know the impact of climate change on biogeochemical cycling of iron because this could have significant impact on the fate and transport of pollutants and organic carbon. In fact, it was recently concluded that iron minerals are a major control in long-term organic carbon sequestration in soils. This study challenges that conclusion since a change in soil redox potential due to flooding could potentially lead to a release of ?sequestered? carbon due to reductive dissolution of iron. Broader Impacts: Improved education and training of a diverse group of students, teachers, and researchers including underrepresented in environmental biogeochemistry will help solve complex environmental problems. Advancing the understanding of climate impacts on biogeochemical cycling of iron benefits society by providing knowledge about potential costly environmental problems that have not been considered up to now and that could lead to increased pollution and further threaten the global water and food supply. Dissemination of results will be conducted broadly at four main levels: 1) Publications in peer-reviewed journals and presentations at national and international conferences are obvious but important routes of dissemination. The PI is a guest editor for an Environmental Science & Technology focus issue on Biogeochemical Redox Processes and their Impact on Contaminant Dynamics. 2) Outreach to High School Teachers and Younger Students: The PI and his students will participate in K12, Building Bridges, and ?High School Day programs at CSU. 3) Workshops and International Outreach: The PI will organize the next Telluride Science Research Center workshop on environmental biogeochemistry and will conduct a workshop in Germany discussing synchrotron radiation based tools in environmental biogeochemistry. 4) Cooperative Extension and Community Outreach: Current research of the PI with the agricultural experiment station has provided an ideal vehicle for dissemination of results to the agricultural community. The PIs research will also be communicated to the public via radio stations and news papers. The CSU School of Global Environmental Sustainability will help meet the ambitious goals of this project.
