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: 0403924
• 负责人: Howard Epstein
• 金额: $ 15.18万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0403924&HistoricalAwards=false
• 关键词: Collaborative; Research; Watershed; Carbon; Distribution

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 ransport, 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.

二氧化碳（CO2）在气候变化和从土壤中去除碱阳离子的主要作用。 然而，二氧化碳产量和流域外排的空间和时间变化仍然鲜为人知。 我们才刚刚开始开发从点测量值（例如通量塔或呼吸室制造的方法）到较大的空间尺度（例如地块或流域）的方法。 在气候，环境，生物地球化学和地形梯度中，主要的二氧化碳迫使因子如何变化。 此外，对C累积的地形控制和动员的互补调查，以及溶解有机碳（DOC）的动员，以了解在分水岭量表下景观与C周期之间的联系的中心。 许多对C分配和运动的调查集中在大气交换上，忽略了溪流中C的损失。 最近的工作使我们深入了解了控制水流C出口的时间和幅度的过程。 我们认为，了解地形控件和溪流捕捉连接是了解集水区总C通量不可或缺的一部分。 与水文相似性有关的生物地球化学相似性的概念已被确定为理解生物地球化学过程空间模式的强大工具。 我们的研究将测试该概念在土壤呼吸和DOC导出中的适用性，并将确定量化土​​壤CO2生产和表面外排的一阶控制所必需的关键测量值。 然后，此派生的信息将为我们的模型提供信息并限制我们的模型，以模拟这些参数通过空间和时间的变异性。 这些空间分布的数据对于模拟土壤CO2的生产和运输至关重要。 通过将广泛的现场测量和量化影响土壤呼吸的因素，例如土壤温度，土壤水分，土壤生育能力和气候变量以及数值建模技术，这项工作将为测量和建模广泛但知之甚少的水，C和土壤和大气之间的能量交换提供了前进的方向。 这项研究的目标是（1）量化二氧化碳外排，并开发和应用流域呼吸模型，结合土壤空气PCO2，溶解CO2的垂直土壤水运输和表面CO2外排，（2）探索可以在驱动呼吸中固定的（3）范围内固有的差异的地形来探索的程度。在景观中积累，DOC Ransport和流媒体DOC出口在流域范围内。 拟议活动的智力优点这项工作将为建立和应用一个框架的基础，以理解土壤呼吸的空间和时间范围，以及由此产生的土壤空气二氧化碳浓度，大气交换和溪流C出口。 拟议活动造成的更广泛的影响。在研究的各个方面都将大学生和研究生纳入了这项工作的主要目标。 弗罗斯特堡州立大学（Frostburg State University）主要是本科生，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 Institation）之间的合作联系，为现在和将来的弗罗斯特堡学生提供经验和机会。 学生将是研究团队不可或缺的成员，并鼓励通过在国家会议上发布和提出调查结果来掌握其贡献。 这项研究将通过在集体练习和基于现场的学习中包含近乎实时的数据来增强教学活动（本科生和研究生）。 这项工作还将加强弗罗斯特堡（Frostburg）的研究基础设施，从而帮助从本科机构中推进学生和教职员工在水文学和生物地球化学领域的人数不足。 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加BSI研究生研究生计划提供更多支持。根据该计划，该研究员将接受有效沟通其成果的培训，以向K-12社区和公众进行培训。 研究员计划为研究生提供培训和机会传达科学，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的使命，即将当前的研究与各个年龄段的人们和各行各业的人们相结合。 这项工作还将产生土壤空气二氧化碳浓度，外排，半分布的现场测量和驱动因素的模拟，以及与流水C出口的链接。 我们的数据集将在网络上免费提供给其他研究人员，并可以用作二氧化碳生产，通量和流水C导出模型的测试数据集。 迄今为止，尚无此类数据集（对作者知识），但这对于通过提供测试场和比较集来理解C跨环境梯度的C积累和通量至关重要。