EAR-PF: Mechanism of Soil Organic Matter Stabilization within Subsurface Soil Aggregates

摘要增枝洋子-SloweyDr. Yoko Masue-Slowey被授予NSF地球科学博士后奖学金，在圣巴巴拉的加州大学（UCSB）开发研究和教育的综合计划。 该项目旨在促进我们对控制地下土壤有机质（SOM）稳定性的机制的理解，同时保持土壤的自然组合。了解有机质周转率及其稳定机制是很重要的，因为大量的碳（2500 Pg）存储在顶部3米的土壤。预测SOM周转率的变化需要了解SOM的稳定机制，考虑土壤的三维结构。本研究将确定SOM的稳定机制，保持其原生结构的地下土壤，并测试如果在总规模的过程变化是净SOM周转时间的主要决定因素。 土壤团聚体内的有机质周转时间将量化在毫米级分辨率使用14 C，和关键的有机质稳定机制，在相应的部分土壤团聚体将确定整合一系列新的技术，包括同步加速器为基础的X射线荧光成像，13 C核磁共振光谱，分子生物测定，和氧化还原测量微电极伏安法。研究团聚体中的氧化还原特征和代谢多样性，以探讨氧化还原控制的代谢速率是否是土壤中的一种保护机制。本研究的一个主要成果将是定量评估的重要性，聚集/ped为基础的异质性在微生物处理碳控制的SOM营业额在地下土壤。具体的培训目标包括获得进行实地研究的经验，学习如何将实验室规模的调查与实地规模的观察联系起来，以及扩大土壤-生态系统相互作用的知识。 该项目将使UCSB，斯坦福大学和美国地质调查局之间的合作，并为高中生创造一个机会，参与动手实验室为基础的研究。

AbstractYoko Masue-SloweyDr. Yoko Masue-Slowey has been awarded an NSF Earth Sciences Postdoctoral Fellowship to develop an integrated program of research and education at the University of California, Santa Barbara (UCSB). The project aims to advance our understanding of mechanisms controlling subsurface soil organic matter (SOM) stabilization while preserving the natural assemblage of soils. Understanding SOM turnover rate and its stabilization mechanisms are important because large amounts of carbon (2500 Pg) are stored in the top 3 m of soils. Predicting changes in SOM turnover rate requires understanding SOM stability mechanisms that consider the three-dimensional architecture of soils. This study will determine SOM stabilization mechanisms within subsurface soils that maintain their native structure and to test if variation in aggregate-scale processes is the prime determinant of net SOM turnover time. SOM turnover time within soil aggregates will be quantified at millimeter-scale resolution using 14C, and key SOM stabilization mechanisms in corresponding sections of soil aggregates will be identified by integrating a range of novel techniques including synchrotron based X-ray fluoresce imaging, 13C nuclear magnetic resonance spectroscopy, molecular bioassay, and redox measurement by microelectrode voltammetry. The redox profile and metabolic diversity within aggregates will be studied to investigate if the redox-controlled metabolic rate is a protection mechanism in soils. A major outcome of this research will be to quantitatively evaluate the importance of aggregate/ped-based heterogeneity in microbial processing of carbon controlling the SOM turnover in subsurface soils. Specific training objectives include gaining experience conducting field site-driven research, learning how to link laboratory-scale investigation to field-scale observations, and expanding the knowledge of coupled soil-ecosystem interactions. This project will enable collaboration between UCSB, Stanford University, and the U.S. Geological Survey, and create an opportunity for high school students to participate in hands-on laboratory-based research.