Collaborative Research: Multiple Stressors in the Estuarine Environment: What drives changes in the Carbon Dioxide system?

合作研究：河口环境中的多重压力源：是什么推动了二氧化碳系统的变化？

• 批准号: 1536996
• 负责人: Raymond Najjar
• 金额: $ 18万
• 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: 2015
• 资助国家: 美国
• 起止时间: 2015-10-01 至 2020-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1536996&HistoricalAwards=false
• 关键词: Collaborative; Research; Multiple; Stressors; Estuarine

Understanding the vulnerability of estuarine ecosystems to anthropogenic impacts requires a quantitative assessment of the dynamic drivers of change to the estuarine carbonate system. Estuaries are currently experiencing multiple environmental stressors that have significant impacts on their carbonate chemistry, making this assessment a major challenge. Although the effects of changes in nutrient run-off (i.e. eutrophication and hypoxia) have been long-studied in many estuaries, much less attention has been given to the impacts of global change on these systems. In this study, a team of field scientists and modelers will attempt to distinguish natural interannual variability in a major US estuary from the impacts of local anthropogenic changes (e.g., nutrient inputs, changing freshwater end member characteristics) and global change (increases in atmospheric temperature, atmospheric carbon dioxide, and sea level), by using numerical models calibrated with CO2-system observations at appropriate spatial and temporal scales. If successful, this will be the first study to quantitatively distinguish between local and global anthropogenic impacts on the CO2 system in an estuary. The results are expected to have important implications for management of Chesapeake Bay because the impact of local anthropogenic stressors on the system, once isolated, may be mitigated by appropriate environmental policy implemented at the regional scale. Two of the PIs have a strong history of proven relationships with Chesapeake Bay managers and policy makers, which will insure direct infusion of these scientific results into ongoing management decisions.In this project researchers will study the diurnal, seasonal, and interannual variability of the CO2 system in the Chesapeake Bay, a non-pristine estuary, using a combination of conventional shipboard sampling (of dissolved inorganic carbon, and alkalinity) and new high-frequency autonomous instrumentation (for observations of pH and CO2 partial pressure) to assess the impact of extreme events, like tropical storms and nor?easters on carbonate chemistry. These high-quality observations will afford a rigorous assessment of the uncertainty associated with a 30-year water-quality monitoring time series of pH and alkalinity. The team will use an estuarine-carbon-biogeochemical model evaluated and calibrated with the new and long-term observations. Sensitivity experiments will be applied to disentangle multiple impacts on the CO2 system in the estuary over the last 30 years, including increased atmospheric temperature and CO2, sea-level rise, eutrophication due to increases in nutrient run-off, and changing carbonate characteristics of riverine end-members.

了解河口生态系统对人为影响的脆弱性，需要定量评估河口碳酸盐系统变化的动态驱动因素。河口目前正在经历多种环境压力，对碳酸盐化学产生重大影响，使这项评估成为一项重大挑战。虽然营养径流（即富营养化和缺氧）的变化的影响已经在许多河口长期研究，很少有人注意到全球变化对这些系统的影响。在这项研究中，一个由实地科学家和建模人员组成的团队将试图区分美国主要河口的自然年际变化与当地人为变化的影响（例如，营养物输入、不断变化的淡水终端成员特征）和全球变化（大气温度、大气二氧化碳和海平面的上升），方法是使用在适当的空间和时间尺度上用CO2系统观测校准的数值模式。 如果成功的话，这将是第一个研究定量区分本地和全球的人为影响的二氧化碳系统在河口。 这些结果预计将有重要的影响，管理的切萨皮克湾，因为当地的人为压力对系统的影响，一旦隔离，可能会减轻适当的环境政策，在区域范围内实施。其中两个PI与切萨皮克湾的管理者和决策者有着牢固的关系，这将确保将这些科学结果直接注入正在进行的管理决策。在本项目中，研究人员将研究切萨皮克湾（一个非原始河口）CO2系统的日变化、季节变化和年际变化，使用常规船上取样和（溶解无机碳和碱度）和新的高频自主仪器（用于观测pH值和CO2分压），以评估极端事件的影响，如热带风暴和nor？碳酸盐化学。这些高质量的观测结果将对与pH值和碱度的30年水质监测时间序列相关的不确定性进行严格评估。该小组将使用一个河口-碳-地球化学模型，该模型根据新的和长期的观测结果进行评估和校准。敏感性实验将被应用到解开在过去30年中，包括大气温度和CO2，海平面上升，富营养化，由于营养径流的增加，并改变河流端成员的碳酸盐特性的河口CO2系统的多重影响。