VANADIUM K-EDGE XANES STUDY OF SOILS AND LEAF LITTER: VANADIUM SPECIATION AND CO

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 在许多生态系统中，碳的固定受到氮素有效性的限制，而异养细菌的氮素固定是陆地系统生物有效氮的重要来源。控制土壤固氮的一个重要因素是V、Mo和Fe的化学形态和生物有效性，因为它们是固氮酶(负责生物固氮的酶)所必需的金属辅因子。由于缺乏关于土壤中钒形态形成的信息，了解土壤中钒的循环和生物有效性的努力受到严重限制。我们最近在SSRL BL4-3收集的有限的钒K边XAS数据(快速响应)表明：(1)即使在低V浓度(

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Carbon fixation in many ecosystems is limited by the availability of nitrogen, and N2 fixation by heterotrophic bacteria is an important source of biologically available nitrogen to terrestrial systems. An important control on nitrogen fixation in soils is the chemical speciation and bioavailability of V, Mo, and Fe because they are required metal cofactors in nitrogenase, the enzyme responsible for biological N2 fixation. Efforts to understand V cycling and bioavailability in soils is severely limited by the dearth of information on V speciation in these environments. Limited vanadium K-edge XAS data we collected recently (rapid response) at SSRL BL 4-3 demonstrated that (1) we can collect high quality XANES data even at the low V concentrations (