Development of an Automated and User-Friendly Technique for Measuring Dissolved Methane and Nitrous Oxide Concentrations

这项研究正在全面开发一种自动化、用户友好、现场便携和成本效益高的技术，用于高精度分析离散海水和淡水样品中溶解的甲烷和一氧化二氮浓度。海洋和淡水甲烷和一氧化二氮系统是这些有效温室气体的大型天然储存库，与大气进行活跃的交换。提出了许多假设，表明海洋温度上升和这些气体排放增加之间存在正反馈。然而，新的、往往出人意料的生产和消费机制正在被发现，这些过程背后的生物地球化学机制正在受到限制，这表明这些系统的动态并不像最初假设的那样简单。虽然这些研究是多种多样的，从局部性质到全球过程，但它们都建立在对甲烷和一氧化二氮溶解浓度的基本测量基础上。然而，实验室之间使用了各种测量技术，最近证明这些技术产生的结果具有很大的实验室间变异性。这里进行的工作是建立一种技术，可以相对容易地在不同的实验室实施，测量这些气体，以提高结果的精确度和实验室间的可比性。除了这项工作将对测量这些溶解气体的研究团体产生广泛的科学影响外，该项目还将对STEM教育产生广泛的影响。正在开发一系列教育模块，以介绍、激励和教育本科生在地球科学方面的技术和仪器开发，这些模块将被纳入罗切斯特大学的一系列研究课程。该项目还支持来自海洋科学中代表性不足的群体的研究生和本科生。对这些分子进行定量分析的高精度分析化学技术必须首先将这些气体从溶解状态转化为气态。因此，这里正在开发的技术结合了真空气体提取和气水平衡的组件，以提高效率，并在全自动平台中提高精度，以提高重复性。该项目认识到，目前测量这些溶解气体浓度的大多数实验室很可能拥有这些气相分析所需的一个或多个相对昂贵的探测器。因此，该项目完全开发了一个相对便宜的“前端”，并免费分发自动化软件，以便该技术可以与各种现有的探测器接口。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This research is fully developing an automated, user-friendly, field-portable, and cost-effective technique for the high-precision analysis of dissolved methane and nitrous oxide concentrations in discrete seawater and freshwater samples. The oceanic and freshwater methane and nitrous oxide systems are large natural reservoirs of these potent greenhouse gases in active exchange with the atmosphere. Numerous hypotheses have been levied suggesting positive feedbacks between increasing ocean temperatures and increasing emissions of these gases. Yet, new and often unexpected production and consumption mechanisms are being discovered and the biogeochemical mechanisms behind these processes are being constrained, suggesting that the dynamics of these systems are not as straightforward as may have originally been hypothesized. While these investigations are diverse spanning local properties to global processes, they are all founded on fundamental measurements of the dissolved concentrations of methane and nitrous oxide. However, a variety of measurement techniques are in use between laboratories which have recently been shown to produce results with substantial interlaboratory variability. The work conducted here is establishing a technique that can be relatively easily implemented into different laboratories measuring these gases for increased precision and interlaboratory comparability of results. Beyond the broad scientific impacts this work will have on the research communities measuring these dissolved gases, this project will also have broad impacts on STEM education. A series of educational modules is being developed to introduce, excite, and educate undergraduate students for technology and instrumentation development in the geosciences, and the modules will be incorporated into a sequence of research courses at the University of Rochester. This project is also supporting graduate and undergraduate students from groups underrepresented in the ocean sciences.High precision analytical chemistry techniques for the quantitative analysis of these molecules must first transfer these gases from the dissolved to gaseous phase. Thus, the technique being developed here incorporates components of both vacuum gas extraction, for increased efficiency, and gas-water equilibration, for increased precision, in a fully automated platform, for increase reproducibility. This project recognizes that most laboratories currently measuring these dissolved gas concentrations likely have one or more of the relatively expensive detectors necessary for these gas-phase analyses. Thus, this project is fully developing a relatively inexpensive “front-end” and freely distributing the automation software, so that this technique can be interfaced with a variety of already available detectors.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.