Biogeochemistry Core

生物地球化学核心将支持代表地球的地球化学和微生物测量 科学和环境工程项目5、6和7以及地下水成分分析， 生物医学项目3和4的潜在健康问题。使用VG Axiom（磁扇区）高- Lamont-Doherty的分辨率电感耦合等离子体质谱仪（HR ICP-MS） 天文台，大约10,000个地下水和沉积物样品将进行分析，多达33个主要和 微量元素现有的方法将被完善，以确定砷的浓度和形态在外地 在实验室里。沉积物沉积速率将在一系列时间尺度上使用 放射性同位素14 C、137 Cs和210 Pb。 通过与达特茅斯学院和保罗·塞尚大学（法国）的合作， 生物地球化学核心将支持铁和砷矿物学的光谱表征， 在各种同步加速器设施中对选定的沉积物样品进行形态分析。这将包括批量分析， X射线吸收近边结构（XANES）和扩展X射线吸收精细结构（EXAFS） 光谱，以及微束X射线微探针分析，以确定空间异质性。 生物地球化学核心还将支持共同努力，以确定微生物负责 地下水中的砷这项工作将在哥伦比亚健康科学校园和 与迪克讷大学合作。使用基于区域性和非基于区域性的方法， 将在美国选定的含水层材料中确定砷代谢细菌的存在， 孟加拉国.地下水和沉积物样品的微生物多样性将采用 16 srRNA和特定基因，如Arr和Ars操纵子。DNA和RNA稳定同位素探测 还将制定方法。

The Biogeochemistry Core will support geochemical and microbiological measurements on behalf of earth science and environmental engineering Projects 5, 6, and 7 and groundwater analyses for constituents of potential health concern for biomedical Projects 3 and 4. Using a VG Axiom (magnetic sector) High- Resolution Inductively Coupled Plasma-Mass Spectrometer (HR ICP-MS) housed at Lamont-Doherty Observatory, approximately 10,000 samples of groundwater and sediment digests will be analyzed for up to 33 major and trace elements. Existing methods will be refined to determine As concentrations and speciation in the field and in the laboratory. Sediment deposition rates will be determined over a range of time scales using the radioisotopes 14C, 137Cs, and 210Pb. Through collaboration with Dartmouth College and the Universite Paul Cezanne (France), the Biogeochemistry Core will support the spectroscopic characterization of Fe and As mineralogy and speciation for selected sediment samples at various synchrotron facilities. This will include bulk analysis by X-ray Absorption Near-Edge Structure (XANES) and Extended X-ray Absorption Fine-Structure (EXAFS) spectroscopy, as well microbeam X-ray microprobe analysis to determine spatial heterogeneity. The Biogeochemistry Core will also support a concerted effort to identify the microorganisms responsible for mobilizing As in groundwater. This work will be conducted on the Columbia Health Sciences campus and in collaboration with Duquesne University. Using both culture-based on non-culture-based methods, the presence of arsenic-metabolizing bacteria will be determined in selected aquifer material from the U.S. and Bangladesh. The microbial diversity of groundwater and sediment samples will be established using 16srRNA and specific genes, such as the Arr and Ars operon. DMA and RNA Stable Isotope-Probing methods will also be developed.