Collaborative Research: Estuarine metabolism and gas exchange determined from dissolved oxygen time series: method development, field evaluation, and application to historical data

合作研究：根据溶解氧时间序列确定河口代谢和气体交换：方法开发、现场评估和历史数据应用

• 批准号: 1924559
• 负责人: Raymond Najjar
• 金额: $ 89.94万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1924559&HistoricalAwards=false
• 关键词: Collaborative; Research; Estuarine; metabolism; gas

Estuaries play a key role in the global cycling of elements because they are hot spots of biological activity and chemical transformations that lie at the interface between land, ocean, and atmosphere. As materials are transported from land to ocean, estuaries profoundly transform or filter these materials through various processes, chief among which are photosynthesis and respiration, collectively referred to as metabolism, and the exchange of gases (such as carbon dioxide and oxygen) between the estuary and the atmosphere. However, these processes are poorly constrained due to lack of sufficient data, high variability in space and time, inconsistent methodology, and lack of a unified model. This research will advance understanding of these processes through a novel combination of field campaigns, model development, and historical data analysis. The data currently available to quantify these processes, which are continuous measurements of dissolved oxygen, are complicated by tidal currents. Hence a main objective of the research is to evaluate and improve methods that remove the influence of tidal currents, which is called advection. This objective will be achieved by direct measurements of advection in two contrasting estuaries in contrasting seasons. Products of this research will be made available to high school teachers, college students, and research professionals. Easy-to-use software based on the open-source R programming language will be developed to analyze the dissolved oxygen data. A Research Experience for Teachers will engage a high school teacher in estuarine metabolism and gas exchange research. Curricular materials for high school and college employing the software will be developed with education specialists. The software will be integrated into the current software suite that is used to analyze dissolved oxygen data from a national data base. A postdoctoral researcher will be involved in all aspects of the broader impacts and gain experience in pedagogy and outreach. The first two objectives of the proposed research are to evaluate and improve advection-removal techniques and gas transfer parameterizations in four one-month field campaigns in contrasting estuaries (Hudson River and Apalachicola Bay) and seasons (spring and late summer). A control volume approach will be adopted, providing a rare opportunity to completely constrain the dissolved oxygen budget at an estuarine location. Achieving these two objectives will allow the following hypotheses to be tested: (H1) advection-removal errors increase as the correlation between sun angle and tidal height increases and (H2) turbidity and fetch measurably influence the gas transfer velocity. The third objective is to develop a new dissolved-oxygen data assimilation method, Estuarine BAyesian Single-station Estimation (EBASE), for simultaneously determining gross primary production, ecosystem respiration, net ecosystem production, and gas exchange. EBASE will combine the advection-removal technique (and its determined errors estimated in the first objective) with Bayesian metabolism techniques recently developed in limnology. EBASE will also retrieve model parameters, such as the initial slope of the photosynthesis-irradiance curve, the temperature dependence of respiration, and the fetch dependence of the gas transfer velocity. The fourth objective is to apply EBASE to the field campaign data and to 16 long-running (at least 14 years), high-quality dissolved oxygen time series within the U.S. National Estuarine Research Reserve System (NERRS), which also contains critical continuous measurements of temperature, salinity, turbidity, wind speed, wind direction, and surface irradiance as well as monthly measurements of chlorophyll and nutrients. EBASE will be applied to one-month segments of the NERRS data, facilitating an analysis of the drivers of seasonal, interannual, and cross-system variability in estuarine metabolism and gas exchange. This analysis will allow further testing of H2 as well as testing of metabolism-related hypotheses: (H3a) the initial slope of the photosynthesis-irradiance curve increases with nutrients and chlorophyll and decreases with turbidity and (H3b) the slope of the respiration-temperature relationship increases with salinity (a proxy of dissolved organic matter) and chlorophyll (a proxy of bacterial abundance).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.

河口在元素的全球循环中起着关键作用，因为它们是土地，海洋和大气之间界面上的生物活性和化学转化的热点。随着材料从陆地传输到海洋，河口通过各种过程深刻地转化或过滤这些材料，其中主要是光合作用和呼吸，共同称为代谢，以及在河口之间的气体交换（例如碳二氧化碳和氧气）和气氛。但是，由于缺乏足够的数据，时空和时间不一致的方法，方法不一致以及缺乏统一模型，这些过程受到限制。这项研究将通过现场运动，模型开发和历史数据分析的新型组合来提高对这些过程的理解。当前可用于量化这些过程的数据，这些过程是溶解氧的连续测量，这是潮流的复杂性。因此，该研究的主要目的是评估和改进消除潮流影响的方法，这称为对流。在对比季节的两个对比河口中，将通过直接测量对流的直接测量来实现这一目标。这项研究的产品将提供给高中教师，大学生和研究专业人员。将开发基于开源R编程语言的易于使用的软件，以分析溶解的氧气数据。教师的研究经验将与一位高中老师参与河口代谢和天然气交换研究。高中和大学使用该软件的课程材料将与教育专家一起开发。该软件将集成到当前软件套件中，该软件用于分析来自国家数据库的溶解氧数据。博士后研究人员将参与更广泛影响的各个方面，并在教学法和外展方面获得经验。拟议的研究的前两个目标是在四个月的河口（哈德逊河和阿帕拉奇科拉湾）和季节（春季和夏季）中评估和改善四个月野外运动中的对流驱动技术和气体传递参数。将采用一种控制量的方法，为在河口位置完全限制溶解的氧气预算提供了难得的机会。实现这两个目标将允许测试以下假设：（H1）对流驱动误差随着日角和潮汐高度之间的相关性的增加而增加，并且（H2）浊度和提取物可测量地影响气体传递速度。第三个目标是开发一种新的溶解氧数据同化方法，河口贝叶斯单站估计（EBASE），以同时确定一级生产，生态系统呼吸，净生态系统生产和气体交换。 EBASE将将对流驱动技术（及其在第一个目标中估计的确定的错误）与最近在林长学中开发的贝叶斯代谢技术相结合。 EBASE还将检索模型参数，例如光合作用iRradise曲线的初始斜率，呼吸的温度依赖性以及气体传递速度的提取依赖性。第四个目标是将eBase应用于现场活动数据，并将16个长期运行（至少14年），高质量溶解的氧气时间序列序列序列序列，其中包括关键的连续测量值温度，盐度，浊度，风速，风向和表面辐照度以及叶绿素和养分的每月测量。 EBASE将应用于NERRS数据的一个月段，促进河口代谢和气体交换中季节性，年际和跨系统变异性的驱动因素的分析。该分析将允许对H2进行进一步测试，并测试与代谢相关的假设：（H3A）光合作用 - iRradiance曲线的初始斜率随营养和叶绿素而增加，并随着浊度和（H3B）的降低而减少。关系随盐度（溶解有机物的代表）和叶绿素（细菌丰度的代表）而增加。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的智力优点和更广泛影响的审查标准通过评估来支持的。