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.

该项目将调查因火灾、热岩溶破坏和永久冻土融化等干扰而大量释放到北极地表水中的溶解有机物 (DOM) 的命运。研究人员假设，新获得的土壤碳将容易受到光化学和微生物的攻击，并将增强系统中常驻 DOM 的降解，导致出口到海洋的 DOM 质量较差。他们计划通过以下方式建立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改变地表水中常驻 DOM 和新释放的 DOM 的速度，以及（B）测量地表水中 DOM 的命运，无论是作为二氧化碳释放到大气中还是作为有机碳改变并运输到沿海海洋。这将通过一系列实验室实验来完成，以确定不同来源的 DOM 的光降解和微生物处理速率，并进行一系列景观比较和样线采样，以表征从源头延伸到北冰洋 250-300 公里的小盆地和大河流中的 DOM 降解。通过将这一基于过程的研究与正在进行的研究热岩溶破坏形成以及燃烧对植物和土壤碳分配影响的项目相结合，研究人员将解决诸如从苔原到海洋的碳输出是否会上升或下降、输出的碳的反应性如何、以及包括气候变化在内的即将发生的干扰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等问题。研究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该项目并进行研究，(2) 参加关于少数族裔辅导策略的研讨会，(3) 开展其他外展活动，包括 PI、研究生和本科生与初中和高中的会谈。数据的呈现将与 NSIDC 和 Arctic LTER 数据管理相协调。