Collaborative Research: Biogeochemical Transformations of Manganese and Toxic Metals in a Changing Riparian System

环境地球化学和生物地球化学项目的这一奖项支持玛莎·康克林、亚利桑那大学、布拉德利·特博、加州大学圣地亚哥分校（斯克里普斯研究所）以及美国地质调查局的克里斯托弗·富勒和贾德森·哈维的合作研究。该奖项由化学、地球科学和海洋科学部以及MPS多学科活动办公室联合颁发。该团队将研究锰和其他有毒金属（锌、镍、钴和铜）在河岸系统中的运动，该系统包含一条接收受污染地下水的河流。特别值得关注的是生物地球化学对Mn（II）衰减的限制，Mn（II）氧化细菌的作用，以及修复方法对这些过程的影响。将进行实验室和实地研究，并对该系统进行建模。现场位于亚利桑那州的皮纳尔溪。溪水（下潜带）带着溶解氧、金属、营养物质和生物活性沉积物涂层重新补给浅层地下水流动路径。本研究的目的是了解在这些条件下细菌Mn（II）氧化和沉淀以及其他金属共沉淀的过程。修复活动可能会改变当地环境，并导致已经沉积在系统中的金属长期释放。研究结果将表明其他金属的去除与Mn的去除是如何耦合的，确定Mn去除和其他微量金属吸附/共沉淀的最佳区域之间的差异，并确定其他金属在Mn氧化物中的稳定性。此外，本研究将确定存在的各种锰氧化细菌，不同菌株之间的关系，以及微生物利用锰的潜在机制。这是一项涉及教师、科学家、研究专家、研究生和本科生的合作努力，涉及四个学科：水化学、水文学、地球化学和微生物学。该研究将阐明锰在锰主导环境系统中金属生物地球化学循环中的作用。

This award in the Environmental Geochemistry and Biogeochemistry Program supports collaborative research by Martha Conklin, University of Arizona, Bradley Tebo, University of California at San Diego (Scripps Institute), and Christopher Fuller and Judson Harvey of the U. S. Geological Survey. The award is jointly made by the Divisions of Chemistry, Earth Sciences, and Ocean Sciences, and the MPS Office of Multidisciplinary Activities. The team will study the movement of manganese and other toxic metals (Zn, Ni, Co, and Cu) in a riparian system that contains a stream that receives contaminated ground water. Of particular concern are the biogeochemical constraints on the attenuation of Mn(II), the role of Mn(II)-oxidizing bacteria, and the effect of remediation methods on these processes. Both laboratory and field studies will be carried out and the system will be modeled. The field site is Pinal Creek, Arizona. Streamwater (hyporheic zone) recharges shallow groundwater flow paths with dissolved oxygen, metals, nutrients, and biologically active sediment coatings. The goal of this research is to understand the process of bacterial Mn(II) oxidation and precipitation along with co-precipitation of other metals under these conditions. Remediation activities may change local environments and cause long-term release of metals already deposited in the system. The results of the study will indicate how removal of other metals is coupled to removal of Mn, identify differences between optimal zones for Mn removal and sorption/coprecipitation of other trace metals, and determine the stability of other metals in the Mn-oxides. In addition, the study will identify the diverse Mn-oxidizing bacteria present, the relationships among different strains, and the underlying mechanisms involved in microbial utilization of manganese.This is a collaborative effort involving faculty, scientists, research specialists, and graduate and undergraduate students in four disciplines: water chemistry, hydrology, geochemistry, and microbiology. The reseach will elucidate the role of manganese in the biogeochemical cycling of metals in a manganese-dominated environmental system.