Collaborative Research: Photodegradation of Dissolved Organic Matter and its Contribution to Surface Water CO2 fluxes and the Carbon Cycle in a River Dominated Ocean Margin

合作研究：溶解有机物的光降解及其对地表水二氧化碳通量和以河流为主的海洋边缘碳循环的贡献

• 批准号: 0850653
• 负责人: Ronald Benner
• 金额: $ 25.38万
• 依托单位: University South Carolina Research Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-01 至 2012-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0850653&HistoricalAwards=false
• 关键词: Collaborative; Research; Photodegradation; Dissolved; Organic

Ocean margins are highly dynamic systems at the land-sea-air interfaces, and they play a disproportionately large role in global carbon fluxes among these reservoirs. River dominated margins receive large quantities of terrigenous dissolved organic matter (DOM) and its chromophoric component (CDOM) that is highly photoreactive and appears to be largely remineralized to CO2 in margin surface waters. Despite the recognized importance of photochemical processes in river dominated margins, the overall significance of photochemistry in surface water CO2 fluxes remains uncertain. In this project, researchers at the University of South Carolina at Columbia and the University of Georgia will develop regional-scale estimates of photochemical and coupled photochemical-microbial carbon (including CO2 and CO) fluxes and removal of terrigenous DOM and CDOM in surface waters of the northern Gulf of Mexico margin. This ocean margin receives major contributions of terrigenous DOM (3 Tg C yr-1) and CDOM from the Mississippi River system. Specific objectives include determination of apparent quantum yields (AQY) for the photoproduction of CO2 and CO, the photochemical removal of DOC, and the coupled photochemical-microbial removal of DOC. Experimentally determined AQYs will be used in combination with field measurements, satellite imagery, and modeling to provide temporally-integrated, regional-scale assessments of photochemically-mediated carbon fluxes in the study region. The project will include improvement of remote-sensing algorithms and the development of regional-scale models for ocean margin carbon cycling. Once developed, this approach can be utilized to provide similar assessments in other river dominated ocean margins. At sea, the project will utilize a ship of opportunity and integrate with a currently funded study investigating total CO2-fluxes and biological processes in the northern Gulf of Mexico margin. This coordination of projects will provide an unprecedented opportunity for understanding the fundamental physical, biological, and photochemical processes controlling air-sea CO2 fluxes in a major river dominated margin. Broader Impacts: Measuring carbon fluxes (specifically CO2 and CO) in ocean margins and identifying the fundamental factors driving these fluxes have been identified as of great importance by the North American Carbon Program and Ocean Carbon and Climate Change programs. This project will provide regional estimates of photochemical and coupled photochemical-microbial carbon fluxes in surface waters of one of the major river dominated margins of the North American continent. This project will provide training, experience and support for a graduate student at each institution. Both principal investigators teach undergraduate and graduate classes that cover various aspects of the carbon cycle, and data collected from this project will be used as specific examples in these classes. This approach of incorporating information from active research programs into the classroom has proven to be very effective for increasing student interest in science and has encouraged undergraduate participation in research.

海洋边缘是陆地-海洋-空气界面上的高度动态系统，它们在这些库之间的全球碳通量中发挥着不成比例的巨大作用。以河流为主的边缘接受大量的陆源溶解有机物 (DOM) 及其发色成分 (CDOM)，这些成分具有高度光反应性，并且似乎在边缘地表水中大部分再矿化为二氧化碳。尽管人们认识到光化学过程在河流主导边缘的重要性，但光化学在地表水二氧化碳通量中的总体意义仍然不确定。在该项目中，南卡罗来纳大学哥伦比亚分校和佐治亚大学的研究人员将对墨西哥湾北部边缘地表水中的光化学和耦合光化学-微生物碳（包括CO2和CO）通量以及陆源DOM和CDOM的去除进行区域尺度的估计。该海洋边缘受到来自密西西比河系统的陆源 DOM (3 Tg C yr-1) 和 CDOM 的主要贡献。具体目标包括测定光产生 CO2 和 CO、光化学去除 DOC 以及光化学-微生物耦合去除 DOC 的表观量子产率 (AQY)。实验确定的 AQY 将与现场测量、卫星图像和建模结合使用，以提供研究区域光化学介导的碳通量的时间综合、区域规模评估。该项目将包括改进遥感算法和开发海洋边缘碳循环的区域尺度模型。一旦开发出来，这种方法可用于在其他河流主导的海洋边缘提供类似的评估。在海上，该项目将利用一艘机遇船，并与目前资助的一项研究相结合，该研究调查墨西哥湾北部边缘的总二氧化碳通量和生物过程。这种项目协调将为了解控制主要河流边缘地区海气二氧化碳通量的基本物理、生物和光化学过程提供前所未有的机会。更广泛的影响：北美碳计划以及海洋碳和气候变化计划认为，测量海洋边缘的碳通量（特别是二氧化碳和二氧化碳）并确定驱动这些通量的基本因素非常重要。该项目将对北美大陆主要河流边缘之一的地表水中的光化学和光化学-微生物耦合碳通量进行区域估计。该项目将为每个机构的研究生提供培训、经验和支持。 两位主要研究人员教授本科生和研究生课程，涵盖碳循环的各个方面，从该项目收集的数据将用作这些课程的具体示例。事实证明，这种将活跃研究项目的信息融入课堂的方法对于提高学生对科学的兴趣非常有效，并鼓励本科生参与研究。