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

知识优势：地下水拥有大量的DIN（溶解无机氮）储备，并延长了停留时间。目前的分析表明，全球20%的DIN转化为N2（通过反硝化作用）发生在含水层中。pi将把重点放在新发现的DIN反应途径上，厌氧氨氧化（anammox）将NH4+与NO2-结合产生N2。虽然厌氧氨氧化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表征，尽管地球化学条件应该促进其活动。初步证据表明，厌氧氨氧化在富氮含水层中可能超过反硝化作用。PIs建议通过一系列实验室和新开发的原位分子和同位素研究，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的联系。本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，以保证其作为地下水运输过程中N损失的重要机制？2)地下水中厌氧氨氧化是否有指示性的化学或同位素特征，有助于其检测和量化？这项工作将首次报道地下水的原位厌氧氨氧化率，并确定微生物氮循环群落（厌氧氨氧化、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命运。广泛影响：该项目通过康涅狄格大学环境科学与工程中心（CESE）提供实习机会。研究生支持提供给UNCW和UCONN。作为康涅狄格大学海岸研究本科专业的协调员，托拜厄斯的独特地位是将这项工作纳入本科教育。该项目利用UNCW本科生研究和奖学金中心，并将帮助支持两个部门荣誉学位。高中生的研究经验将在UNCW的“夏季海洋冒险”项目中获得，参与者将帮助进行DNA分析，研究生将担任导师。该项目将支持一个关于将地下水DIN污染与沿海富营养化联系起来的公开讲座，该讲座是康涅狄格大学“沿海前景”和康涅狄格大学“海洋星球”系列公开讲座的一部分。增加地下水厌氧氨氧化的成功努力可能会导致补救建议，这些建议可以通过马萨诸塞州美国地质勘测局地区办事处转交给区域经理。

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.