Reduction of iron and humic substances as a dominant respiratory process in arctic peat soils

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AbstractProposal: Reduction of iron and humic substances as a dominant respiratory process in arctic peat soilsP.I.:David Lipson San Diego State UniversityLars T. Angenent Washington UniversityTheodore K. RaabStanford UniversityProposal # 0808604 Investigators from San Diego State University, Washington University, and Stanford University will collaborate to study the role of iron and humic substances as electron acceptors in anaerobic respiration in peat soils of drained thaw lake basins in the Arctic. The role of microbial physiology in carbon flux from Arctic soils has substantial implications of climate change, and the PIs will apply novel methods that promise new insights. The study will further our understanding of controls over and seasonal and spatial variability in of carbon fluxes from Arctic soils. The goals are to: (1) determine the specific mechanisms of exocellular electron transfer in Alaskan peat soils, and the microorganisms that mediate these processes, (2) quantify the importance of exocellular electron transfer to soil respiration in Arctic drained thaw lake basins, (3) determine the effects of polygon-induced microtopography on exocellular electron transfer, and (4) determine how age and complexity of soil humic materials along a soil age gradient affect rates of exo-electron transfer, and the conditions under which it occurs.