Collaborative Research: Anammox in a shallow coastal aquifer - combining in situ stable isotope and molecular approaches to examine controls on rates and communities

智力优势：地下水拥有大量的DIN(溶解无机氮)储备，具有较长的停留时间。目前的分析表明，全球20%的DIN转化为氮气(通过反硝化作用)发生在含水层。PIs将专注于新发现的DIN反应途径--厌氧氨氧化(Anammox)，它将NH4+与NO2-结合生成氮气。虽然Anammox已被证明是许多海洋系统中DIN损失的重要途径，但在地下水环境中几乎完全没有特征，尽管地球化学条件应该促进其活性。初步证据表明，在富N含水层中，Anammox可能超过了反硝化作用。PIS建议通过一系列实验室和新开发的现场分子和同位素研究，在地球化学和微生物水平上研究厌氧氨氧化及其与反硝化和硝化作用的联系(S)。这项研究的总体目标是解决以下问题：1)厌氧氨氧化是否以足够的原位速率发生，足以证明它是地下水运输过程中氮素损失的重要机制？2)地下水中厌氧氨氧化是否具有指示性的化学或同位素特征，可以帮助其检测和定量？拟议的工作将产生首次报告的地下水原位厌氧氨氧化速率，并确定微生物氮循环群落(厌氨氧化、反硝化、硝化)如何以互惠或竞争的方式相互作用，以调节含水层中的氮素命运。更广泛的影响：该项目通过康涅狄格州环境科学与工程中心(CESE)提供实习机会。研究生资助提供给联合国大学和康涅狄格州大学。托拜厄斯作为康涅狄格州大学海岸研究本科专业的协调员，在将这项工作纳入本科教育方面具有独特的地位。该项目利用了世界大学本科生研究和奖学金中心，并将帮助支持两个系荣誉学位。高中学生的研究经验将在联合国世界贸易组织的“夏季海洋冒险”项目中实现，参与者将帮助进行DNA分析，研究生将担任导师。该项目将支持一场关于将地下水DIN污染与沿海富营养化联系起来的公开讲座，这是康涅狄格州大学的“海岸展望”和联合国儿童基金会的“行星海洋”公开讲座系列的一部分。成功地加强地下水Anammox的努力可能会产生补救建议，这些建议可以通过马萨诸塞州USGS区办事处转交给区域管理人员。

Intellectual merit: Groundwater holds a large reserve of DIN (dissolved inorganic nitrogen) with extended residence times. Current analysis suggests that 20% of global DIN conversion to N2 (via denitrification) occurs in aquifers. The PIs will focus their efforts on a newly discovered DIN reaction pathway, anaerobic ammonium oxidation (anammox) that combines NH4+ with NO2- to produce N2. Although anammox has proven to be an important route of DIN loss in many marine systems, it is almost completely uncharacterized in groundwater environments despite geochemical conditions that should promote its activity. The preliminary evidence suggests that anammox may exceed denitrification in N-rich aquifers. The PIs propose to investigate anammox, and its connection(s) to denitrification and nitrification at the geochemical and microbial levels through a series of laboratory and newly developed in situ molecular and isotopic investigations. The overall goal of this study is to address the following questions: 1) Does anammox occur at sufficient in situ rates to warrant its consideration as an important mechanism of N loss during groundwater transport? 2) Are there indicative chemical or isotopic signatures for anammox in groundwater that can aid in its detection and quantification? The proposed work will yield the first reported in situ anammox rates for groundwater and define how microbial nitrogen cycling communities (anammox, denitrification, nitrification) interact in a mutualistic or competitive fashion to regulate nitrogen fate in aquifers. Broader impacts: The project provides internship opportunities through the UCONN Center for Environmental Science and Engineering (CESE). Graduate student support is provided to UNCW and UCONN. Tobias is in a unique position as Coordinator for the UCONN Coastal Studies undergraduate major to incorporate this work into undergraduate education. The project leverages the UNCW Center for Undergraduate Research and Fellowship and will help support two departmental honors degrees. Research experience for high school students will be achieved within the UNCW "Summer Ocean Ventures" program where participants will help with DNA analysis and graduate students act as mentors. The project will support a public lecture on connecting groundwater DIN contamination to coastal eutrophication as part of UCONN's "Coastal Perspectives" and UNCW's "Planet Ocean" public lecture series. Successful efforts to augment groundwater anammox may result in remediation recommendations that can be transferred to regional managers through the Massachusetts USGS district office.