Collaborative Research: Watershed Carbon Distribution and Flux Across Environmental Gradients

合作研究：流域碳分布和跨环境梯度的通量

• 批准号: 0404130
• 负责人: Brian McGlynn
• 金额: $ 34.7万
• 依托单位: Montana State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0404130&HistoricalAwards=false
• 关键词: Collaborative; Research; Watershed; Carbon; Distribution

0404130McGlynn Watershed carbon distribution and flux across environmental gradients The central roles of carbon dioxide (CO2) in climate change and the removal of base cations from soils has been established. However, the spatial and temporal variation of CO2 production and efflux from catchment soils remains poorly understood. We are just beginning to develop the methods to up-scale from point measurements such as those made by flux towers or respiration chambers to larger spatial scales such as plots or watersheds. How the primary CO2 forcing factors vary across climatic, environmental, biogeochemical, and topographic gradients needs to be addressed. In addition, complementary investigation of the topographic controls on C accumulation and the mobilization of dissolved organic carbon (DOC) s central to understanding the links between the landscape and the C cycle at the watershed scale. Many investigations of C allocation and movement focus on atmospheric exchange, neglecting the loss of C in stream water. Recent work has given us insight into the processes controlling the timing and magnitude of stream water C exports. We believe that understanding topographic controls and stream-catchment connections are integral to understanding total C flux from catchments. The concept of biogeochemical similarity, related to hydrological similarity, has been identified as a powerful tool in understanding the spatial patterns of biogeochemical processes. Our research will test the applicability of this concept for soil respiration and DOC export and will identify the critical set of measurements necessary to quantify the spatial and temporal variability in the first-order controls on soil CO2 production and surface efflux. This field-derived information will then inform and constrain our model that simulates the variability of these parameters through space and time. These spatially distributed data are central to simulation of the production and transport of soil CO2. By combining extensive field measurements and quantification of the factors influencing soil respiration such as soil temperature, soil moisture, soil fertility, and climatic variables with numerical modeling techniques, this work will provide a way forward for measuring and modeling the extensive but poorly understood exchange of water, C, and energy between soils and the atmosphere. The objectives of this research are (1) to quantify CO2 efflux and to develop and apply a model of catchment respiration, incorporating soil air pCO2, vertical soil water transport of dissolved CO2, and surface CO2 efflux, (2) to explore the extent to which topography can be used to explain the variability inherent in the factors driving respiration, and (3) To quantify the topographic controls on the distribution of soil C in the watershed and link C accumulation in the landscape, DOC transport, and stream DOC export at the watershed scale. Intellectual merit of the proposed activity This work will provide empirical information and the foundation for development and application of a framework for understanding the spatial and temporal variably of soil respiration and resultant soil air CO2 concentration, atmospheric exchange, and streamwater C export. Broader impacts resulting from the proposed activity. The inclusion of undergraduates and graduate students in all aspects of research is a primary goal of this work. Frostburg State University is a predominantly undergraduate institution, and as such, has limited opportunities for undergraduates to obtain research experience. This research will provide Frostburg students, both now and in the future with experience and opportunities through collaborative linkages made between Frostburg State University, The University of Virginia, and Montana State University (EPSCoR institution). Students will be integral members of the research team and will be encouraged to take ownership of their contributions through publication and presentation of their findings at national meetings. This research will enhance teaching activities (undergraduate and graduate) through inclusion of near real-time data in class exercises and field-based learning. This work will also strengthen the research infrastructure at Frostburg, helping to advance students and faculty from undergraduate institutions that are underrepresented in the fields of hydrology and biogeochemistry. If funded, the Big Sky Institute for Science and Natural History has agreed to provide additional support for participation of a graduate student in the BSI Graduate Fellows Program. Under that program, the Fellow would receive training in effective communication of their results to K-12 communities and the public. The fellows program provides graduate students training and opportunities to communicate science, encourages young scientists to understand their role in disseminating scientific findings to the public, and helps fulfill BSI.s mission of combining current research with inquiry-based learning for people of all ages and all walks of life. This work will also produce a dataset of soil air CO2 concentrations, efflux, semi-distributed field measurements and simulations of driving factors through time, and links to streamwater C export. Our datasets will be made freely available on the web to other researchers and can serve as a test data set for models of CO2 production, flux, and streamwater C export. To date, no such dataset is available (to the authors. knowledge), yet this is critical to understanding C accumulation and flux across environmental gradients by providing a testing ground and comparison set.

0404130McGlynn 流域碳分布和环境梯度通量 二氧化碳 (CO2) 在气候变化和土壤中碱性阳离子去除中的核心作用已经确定。 然而，人们对流域土壤二氧化碳产生和流出的时空变化仍然知之甚少。 我们刚刚开始开发从点测量（例如通量塔或呼吸室进行的测量）扩展到更大空间尺度（例如地块或流域）的方法。 需要解决主要二氧化碳强迫因素如何随气候、环境、生物地球化学和地形梯度变化的问题。 此外，地形对碳积累和溶解有机碳（DOC）动员的补充研究对于理解流域尺度的景观和碳循环之间的联系至关重要。 许多关于碳分配和运动的研究都集中在大气交换上，忽视了溪流水中碳的损失。 最近的工作让我们深入了解了控制溪流水 C 输出的时间和幅度的过程。 我们相信，了解地形控制和河流与流域的连接对于了解流域的总碳通量至关重要。 与水文相似性相关的生物地球化学相似性概念已被认为是理解生物地球化学过程空间模式的有力工具。 我们的研究将测试这一概念对土壤呼吸和 DOC 输出的适用性，并将确定量化土​​壤二氧化碳产生和地表流出的一阶控制中的空间和时间变异性所需的关键测量集。 然后，这些来自场的信息将通知并约束我们的模型，该模型模拟这些参数随空间和时间的变化。 这些空间分布的数据对于模拟土壤二氧化碳的产生和运输至关重要。 通过将影响土壤呼吸的因素（如土壤温度、土壤湿度、土壤肥力和气候变量）的广泛现场测量和量化与数值模拟技术相结合，这项工作将为测量和模拟土壤与大气之间广泛但知之甚少的水、碳和能量交换提供一条前进的道路。 本研究的目标是 (1) 量化 CO2 流出并开发和应用流域呼吸模型，其中包括土壤空气 pCO2、溶解 CO2 的垂直土壤水输送和地表 CO2 流出，(2) 探索地形在多大程度上可用于解释驱动呼吸的因素中固有的变异性，以及 (3) 量化地形对流域和连接 C 中土壤 C 分布的控制。 流域尺度的景观积累、DOC 传输和河流 DOC 输出。 拟议活动的智力价值这项工作将为开发和应用一个框架提供经验信息和基础，以了解土壤呼吸的空间和时间变化以及由此产生的土壤空气二氧化碳浓度、大气交换和河水碳输出。 拟议活动产生更广泛的影响。让本科生和研究生参与各个方面的研究是这项工作的主要目标。 弗罗斯特堡州立大学是一所以本科生为主的机构，因此本科生获得研究经验的机会有限。 这项研究将通过弗罗斯特堡州立大学、弗吉尼亚大学和蒙大拿州立大学（EPSCoR 机构）之间的合作联系，为现在和未来的弗罗斯特堡学生提供经验和机会。 学生将成为研究团队不可或缺的成员，并将被鼓励通过在全国会议上发表和展示他们的发现来承担自己的贡献。 这项研究将通过在课堂练习和实地学习中纳入近实时数据来加强教学活动（本科生和研究生）。 这项工作还将加强弗罗斯特堡的研究基础设施，帮助提高水文学和生物地球化学领域代表性不足的本科院校的学生和教师的水平。 如果获得资助，大天空科学与自然历史研究所已同意为研究生参与 BSI 研究生项目提供额外支持。根据该计划，研究员将接受培训，以便向 K-12 社区和公众有效传达其研究结果。 该研究员计划为研究生提供培训和交流科学的机会，鼓励年轻科学家了解他们在向公众传播科学发现方面的作用，并帮助实现 BSI. 将当前研究与面向各年龄段和各行各业的人们的基于探究的学习相结合的使命。 这项工作还将产生土壤空气二氧化碳浓度、流出量、半分布式现场测量和随时间变化的驱动因素模拟的数据集，以及与溪流水碳输出的链接。 我们的数据集将在网络上免费提供给其他研究人员，并可作为二氧化碳产生、通量和溪流 C 输出模型的测试数据集。 迄今为止，还没有这样的数据集（据作者所知），但这对于通过提供试验场和比较集来了解跨环境梯度的碳积累和通量至关重要。