Reduction of iron and humic substances as a dominant respiratory process in Arctic peat soils, 2008-2012

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. Award number: OPP 0808604 Sponsor: San Diego State University Foundation, 5250 Campanile Drive, San Diego, CA 92182-2190 Award Program: Arctic Natural Sciences (ANS)来自圣地亚哥州立大学、华盛顿大学与斯坦福大学的研究人员将展开合作，研究铁与腐殖质（humic substances）作为电子受体，在北极排水解冻湖盆（drained thaw lake basins）泥炭土壤的厌氧呼吸（anaerobic respiration）过程中所发挥的作用。微生物生理过程在北极土壤碳通量（carbon flux）中的作用与气候变化密切相关，本项目的首席研究员（Principal Investigators, PIs）将采用创新性研究方法，有望获得全新的研究见解。本研究将加深我们对北极土壤碳通量调控机制及其季节与空间变异特征的认知，具体目标如下：（1）阐明阿拉斯加泥炭土壤中胞外电子转移（exocellular electron transfer）的具体机制，以及介导该过程的微生物类群；（2）量化胞外电子转移在北极排水解冻湖盆土壤呼吸中的重要性；（3）明确冰楔多边形诱导微地形（polygon-induced microtopography）对胞外电子转移的影响；（4）探明沿土壤年龄梯度分布的土壤腐殖质的年龄与复杂度如何影响胞外电子转移速率，以及该过程发生的环境条件。资助编号：OPP 0808604；资助方：圣地亚哥州立大学基金会，地址：加利福尼亚州圣地亚哥市坎帕尼莱大道5250号，邮编92182-2190；资助项目：北极自然科学（Arctic Natural Sciences, ANS）