Collaborative research: Turning on the lights - Photochemical and microbial processing of newly exposed carbon in arctic ecosystems

合作研究：打开灯——北极生态系统中新暴露碳的光化学和微生物处理

• 批准号: 1022876
• 负责人: George Kling
• 金额: $ 28.77万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-15 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1022876&HistoricalAwards=false
• 关键词: Collaborative; research; Turning; lights; Photochemical

This project will investigate the fate of dissolved organic matter (DOM) released in increasing amounts to Arctic surface waters through such disturbances as fire, thermokarst failure, and thawing of permafrost. The investigators hypothesize that newly available soil carbon will be labile to photochemical and microbial attack, and will enhance the degradation of resident DOM in the system resulting in poorer quality DOM exported to the ocean. They plan to develop a mechanistic understanding of these processes by: (A) Determining how fast photochemical reactions and microbial processing will alter resident DOM and the newly-released DOM in surface waters, and (B) Measuring the fate of DOM in surface waters, either as CO2 released to the atmosphere or as organic carbon altered and transported to coastal oceans. This would be accomplished with a series of laboratory experiments to determine rates of photodegradation and microbial processing of DOM from different sources, and a series of landscape comparisons and sampling transects to characterize DOM degradation in small basins and large rivers extending 250-300 km from the headwaters to the Arctic Ocean. By integrating this process-based research with ongoing projects studying the formation of thermokarst failures and the impacts of burning on plant and soil carbon allocation, the investigators will address questions such as whether carbon export from tundra to oceans will rise or fall, how reactive is that exported carbon, and what will be the ultimate impact of impending disturbances, including climate change, on the net carbon balance of the Arctic and its interaction with the global carbon cycle. The investigators will work with several established programs at UNC and UM to (1) recruit women and minority student participation and research in this project specifically from Historically Black Colleges, (2) participate in a workshop on mentoring strategies for minorities, and (3) develop additional outreach activities, including talks to middle and high schools by the PIs, graduate, and undergraduate students. Presentation of data will coordinate with NSIDC and Arctic LTER data management.

该项目将调查通过火灾、热岩溶破坏和永久冻土融化等扰动，越来越多的溶解有机物(DOM)释放到北极地表水域的命运。研究人员假设，新的土壤有效碳对光化学和微生物攻击不稳定，并将促进系统中驻留的DOM的降解，导致输出到海洋的质量较差的DOM。他们计划通过以下方式发展对这些过程的机械理解：(A)确定光化学反应和微生物处理将以多快的速度改变地表水中驻留的DOM和新释放的DOM，以及(B)测量DOM在地表水中的命运，无论是二氧化碳释放到大气中，还是作为有机碳改变并输送到沿海海洋。要做到这一点，需要进行一系列实验室实验，以确定来自不同来源的DOM的光降解和微生物处理速率，并进行一系列景观比较和取样横断面，以确定从源头到北冰洋250-300公里的小流域和大河流中DOM的降解特征。通过将这一以过程为基础的研究与正在进行的研究热岩溶失败的形成和燃烧对植物和土壤碳分配的影响的项目相结合，研究人员将解决以下问题：从冻土带向海洋输出的碳是增加还是减少，输出的碳的反应如何，包括气候变化在内的迫在眉睫的扰动对北极净碳平衡及其与全球碳循环的相互作用的最终影响。调查人员将与北卡罗来纳大学和密歇根大学的几个既定项目合作：(1)招募女性和少数族裔学生参与和研究这个项目，特别是从历史上的黑人学院；(2)参加针对少数族裔的指导战略研讨会；以及(3)开展额外的外联活动，包括由PI、研究生和本科生向初中和高中发表演讲。数据的提交将与NSIDC和北极LTER数据管理协调。