CAREER: The Role of Iron and Reactive Oxygen Species in the Oxidation and Fate of DOM in Natural Waters

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

Title: The role of iron and reactive oxygen species in the oxidation and fate of DOM in natural waters This study will determine the direct and indirect roles of iron in both light and dark reactions involving DOM degradation, and estimate the importance of iron in determining whether this degradation will shunt C as DOM down rivers to oceans, or fully oxidize C to CO2 released to the atmosphere. The proposed work will advance our understanding of the degradation of soil carbon exposed to oxygen or sunlight at Earth?s surface during land-surface disturbances. This knowledge will allow scientists to better predict the fate of C in arctic permafrost soils, and through an education and outreach plan, will allow society to better prepare for the potential acceleration of global warming through a positive feedback from the thawing Arctic. To engage underrepresented students in science, the PI proposes to expand the infrastructure of education through partnerships that will offer new opportunities to enhance teaching and communication skills. The PI will develop a curriculum in earth and environmental science integrated with her research, grounded in core education principles, and mapped to assessment goals. A novel contribution to curriculum development will be the combination of (1) education modules that ?telescope? in age-context and difficulty from K-12 to undergraduate to adult outreach levels, (2) data generation on student engagement and learning through micro-assessments of performance, and (3) enhanced active learning by iterative improvement of modules by students for their own peer groups. This research will be done in the Alaskan Arctic because (1) the lakes, streams, and soil waters provide a natural experimental matrix of both high and low light, oxygen, DOM and Fe concentrations, and (2) there are tremendous stores of organic C in frozen soils (at least twice the amount of C now in the atmosphere) which are rapidly thawing from global warming. Using field surveys and experiments on natural waters to test mechanistic hypotheses, the PI will answer two main research questions: (1) Do reactions mediated by iron favor the complete oxidation of DOM to CO2 by sunlight and microbes? (2) Is the iron-mediated oxidation of DOM in the dark an important determinant of DOM fate?