Collaborative Research: Climate effects on Mn oxidation states in soils and Mn/SOM interactions

该研究项目旨在了解元素锰（Mn）在驱动土壤有机质（SOM）降解中的作用。 锰在土壤中有多种化学形式，这取决于土壤中的氧气供应和酸度;其中一些形式在驱动SOM降解方面比其他形式更活跃。 这项拟议的研究将使用高科技工具的组合来评估锰的形式，并通过实验来评估这些形式与SOM以及土壤细菌和真菌的种群和活性的相互作用。 该项目还将为本科生和研究生提供研究培训机会，并有机会扩大代表性不足的群体成员对科学的参与，包括对夏威夷土著人的社区宣传。SOM是生物圈中最大的潜在活性碳（C）库，但其中大部分C转化缓慢，因为它具有化学顽固性和/或物理保护性。Mn可以覆盖这种不稳定性，通过与其三种氧化态相关的多种途径驱动SOM分解。该项目将评估锰的氧化态如何随降雨量变化，以及锰的不同氧化态如何驱动SOM的分解。 野外工作将在夏威夷群岛的一个明确的降水梯度上进行，在这个梯度上，当气候变化很大时，生态系统过程的大多数潜在控制都可以保持相对恒定（年降水量从300毫米/年增加到3200毫米/年），并以明确的方式进行;它还利用了来自国家生态观测网络（氖）的信息和其他网站，以评估锰氧化态和它们的影响，在广泛的网站，不同的其他因素，除了沉淀，作为一个假设，沉淀是锰氧化态的主要驱动程序和其后果SOM稳定性的测试。该项目将建立在与夏威夷原住民社区组织（Ulu Mau Puanui [UMP]）的持续伙伴关系的基础上，该组织正在恢复本研究项目中使用的同一实地的传统农业系统。该项目的科学家和学生将与UMP合作开发课程，并接触每年访问该网站的600多名学习者（其中约一半是夏威夷土著人）中的许多人;它还将与夏威夷土著科学家合作，评估Mn在夏威夷传统农业系统中的作用。该项目将包括本科生和研究生谁属于科学代表性不足的群体。最后，该项目将参加怀俄明州大学的一个完善的暑期项目，以扩大科学中代表性不足的群体的成员的参与。该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

This research project seeks to understand the role that the element manganese (Mn) plays in driving the degradation of soil organic matter (SOM). Mn takes multiple chemical forms in the soil, depending on oxygen availability and acidity in the soil; some of these forms are more active in driving the degradation of SOM than others. This proposed research will use a combination of high-technology tools to evaluate the forms of Mn, and experiments to evaluate the interactions of these forms with SOM and with the populations and activity of soil bacteria and fungi. The project will also afford research training opportunities for undergraduate and graduate students and opportunities to broaden participation of members of underrepresented groups in science, including community outreach to Native Hawaiians. SOM is the largest pool of potentially active carbon (C) in the biosphere, but much of that C turns over slowly because it is chemically recalcitrant and/or physically protected. Mn can override this recalcitrance, driving SOM breakdown through multiple pathways that relate to its three oxidation states. This project will evaluate how the oxidation state of Mn varies as a function of rainfall, and how the different oxidation states of Mn drive the decomposition of SOM. Fieldwork will take place on a well-defined precipitation gradient in the Hawaiian Islands, on which most potential controls of ecosystem processes can be held relatively constant while climate varies widely (from 300 mm/yr annual precipitation to 3200 mm/yr) and in well-defined ways; it also draws upon information from National Ecological Observatory Network (NEON) and other sites to evaluate Mn oxidation states and their implications in a broad range of sites that differ in other factors in addition to precipitation, as a test of the hypothesis that precipitation is the dominant driver of Mn oxidation states and its consequences to SOM stability. This project will build upon an ongoing partnership with a Native Hawaiian community organization (Ulu Mau Puanui [UMP]) that is restoring a traditional agricultural system at the same field sites will be used in this research project. Scientists and students in this project will work with UMP to develop curricula and to reach many of the 600+ learners (about half of whom are Native Hawaiian) who visit the site each year; it will also collaborate with Native Hawaiian scientists to evaluate the role of Mn in traditional Hawaiian agricultural systems. The project will include undergraduate and graduate students who belong to underrepresented groups in science. Finally, the project will take part in a well-established summer program at the University of Wyoming to broaden participation of members of underrepresented groups in science.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.