CAREER: Organic Matter Cycling in the Upper Ocean: Insights from time-series measurements of d15N and D14C in the California Current System

海洋溶解有机物（DOM）水库往往被概念化为一个“电容器”的碳，因为它的存储和交换与其他活动水库的潜力。然而，尽管其规模和潜在的重要性，DOM的动态还没有得到充分的评估，因此，这个水库的最终作用，全球和海洋碳和氮循环仍然有待确定。为了解决复杂的DOM水库的动态，一个年轻的研究人员从加州圣地亚哥大学将开发一个空间分辨的时间序列的分数特定的d15 N和D14 C测量DOM。该时间序列将被放置在加州海流系统内，该系统在各种时间尺度上（例如季节性、年际、十年期）经历物理/气候变率。与气候相关的扰动（加深/变浅温跃层或营养跃层，风场的变化）预计将导致可测量的地表无机溶解CO2和NO3-池的同位素组成的偏移。这些游览最终记录的有机物组分，最近产生的地表沃茨，当放置在一个时间序列的背景下，特定馏分的同位素变异性，将首次直接识别DOM循环每年到几十年的时间尺度。此外，时间序列还将有助于确定地表沃茨中难降解和年轻DOM成分的相对比例，并描述控制DOM库的大小和年龄的一些物理和生物过程。作为该职业奖的一部分，将创建一个新的，基于探究的本科课程，以将气候-海洋-大气等大尺度现象与海洋物理-化学-生物等小尺度现象之间的理论耦合置于有形的，特定区域的，现实世界的框架内。 本课程的一个基本目标将是让学生体验学习科学如何“工作”;学生将设计使用存档的时间序列数据的课程项目，以探索上述连接，并收集为期4-7天的教育巡航到加州当前系统的海洋学数据。在更广泛的影响中，这项研究将是对气候和地球化学之间相互关系的最全面、最长期的调查之一。该地区正在进行的大型科学计划的基础设施将提供背景，并通过基于网络的工具以及书面和口头交流，加强将作为本提案一部分收集的科学数据传播给广大受众。通过教育和推广计划的四个具体目标，PI将教授和指导~100名本科生，指导~8名高中生，使两个学生群体成为更挑剔，更好的环境决策者，为~8名教育工作者提供宝贵的科学经验，带回他们自己的教室，从而接触到更多的学生，还提供~100名，000名市民在自己的后院拥有一个了解海洋生态系统的宝贵窗口。此外，将成为目标的高中生代表了圣地亚哥县一些服务最不足的年轻人。

The marine dissolved organic matter (DOM) reservoir is often conceptualized as a "capacitor" for carbon because of its potential for storage and exchange with the other active reservoirs. Yet, despite its size and potential importance, the dynamics of DOM have not been fully assessed, and therefore the ultimate role of this reservoir for the global and marine carbon and nitrogen cycle remains to be established. To resolve the dynamics of the complex DOM reservoir, a young investigator from the University of California San Diego will develop a spatially resolved time-series of fraction-specific d15N and D14C measurements of DOM. This time series will be placed within the California Current System which experiences physical/climate variability on a variety of timescales (e.g. seasonal, interannual, decadal). The climate-associated disturbances (deepening/shoaling thermocline or nutricline, changes in wind field) are expected to lead to measurable excursions in the isotopic composition of surface inorganic dissolved CO2 and NO3-pools. These excursions are ultimately recorded by organic matter fractions that are recently produced in surface waters; and when placed within the context of a time series, fraction-specific isotopic variability will, for the first time, directly identify DOM cycling on annual to multidecadal timescales. In addition, the time series will also help identify relative proportions of refractory and young DOM components in surface waters and delineate some of the physical and biological processes that control the size and age of the DOM reservoir. As part of this CAREER award, a new, inquiry based, undergraduate course will be created to place the theoretical coupling between large scale phenomena such as climate-ocean-atmosphere and smaller scale phenomena such as ocean physics-chemistry-biology within a tangible, region-specific, real-world framework. A fundamental goal of this course will be for students to learn experientially how science "works"; students will design class projects that use archived time-series data to explore the above connections and collect oceanographic data on a 4-7 day educational cruise to the California Current System. Among the broader impacts, this study will be one of the most comprehensive, long-term investigations of the interrelation between climate and biogeochemistry. The infrastructure of the larger, ongoing scientific programs in the region will provide context, and enhance the dissemination of scientific data collected as part of this proposal to a broad audience through both web-based tools and written and verbal communication. Through the four specific goals of the Education and Outreach plan, the PI will teach and mentor ~100 undergraduates, mentor ~8 high school students, empower both student groups to be more critical, better environmental decision-makers, provide ~8 educators with valuable scientific experience to take back to their own classrooms and so reach even a larger number of students, and also provide ~100,000 citizens with a valuable window into the marine ecosystem in their own backyards. In addition, the high school students that will be targeted represent some of the most under-served youths in San Diego County.