CAREER: The Impact of Hydrologic State on CO2 Flux and Acidification in Subtropical Estuaries

这个项目是授予德克萨斯农工大学科珀斯·克里斯蒂的胡新平职业生涯奖。胡建议将研究和教育整合到德克萨斯州南部的使命-阿兰萨斯河口的碳循环和海洋酸化调查中。这一沿海系统受到河流流量在季节之间和每年之间的变化的强烈影响。河口河流流量变化与碳循环之间的关系还没有得到很好的理解。这种缺乏理解反过来又增加了估计全球河口碳预算的不确定性。此外，气候变化和其他人类活动严重影响河口和沿海海洋的河流输入，进而影响这些环境中的生物地球化学和新陈代谢。尽管需要这些信息，但能够帮助解决这些生态系统中二氧化碳通量强度和方向变化的长期记录非常罕见。利用高强度实地采样和对历史数据的分析，该项目旨在提高对该河口和整个沿海海洋中碳循环的了解。这项研究的结果还将提供有关河口对不断变化的水文条件的生物地球化学响应的关键信息，因为美国西南部变得更加干燥，总体降水量减少。本项目的研究目标包括：1)以亚热带半干旱河口-阿兰萨斯河口为例，调查水文状态与河口二氧化碳分压(PCO2)的关系；2)了解墨西哥湾西北部世界上最大的泻湖河口系统之一的二氧化碳通量及其水文控制的程度；3)阐明导致河口酸化的机制及其对二氧化碳通量的反馈。将开展密集的实地活动，进行高时间分辨率的二氧化碳和碳酸盐水化学采样以及沉积物培养；将利用德克萨斯州环境质量委员会收集的数十年碳酸盐化学参数分析，在该地区淡水日益稀缺的背景下，获得河口水二氧化碳的时间趋势。该职业奖的教育部分包括1)创建海洋与河口酸化研究课程，并为本科生和研究生重新设计两门现有课程；2)与Foy Moody高中合作开展水产科学教育，吸引主要来自代表性不足和经济困难背景的高中生参与实地和实验室体验。最终的教育目标是鼓励高中生走STEM道路接受大学教育，鼓励本科生攻读研究生学位。这将是加强未来劳动力多样性的共同努力的一部分，方法是增加在STEM领域拥有学士学位或更高学位的人数不足的毕业生。该项目将培养一名博士生。来自代表性不足和经济困难背景的高中生和本科生实习生也将得到支持，参加暑期研究。项目成果的广泛传播将包括在TAMU-CC和德克萨斯农工大学系统举办的研讨会上发表本科生报告，在地区河口项目组织的各种会议上由研究生和首席研究员举行的公开研讨会，在国内和国际会议上的陈述，以及在同行评议期刊上发表文章。

This project is a CAREER award to Xinping Hu at Texas A&M University-Corpus Christi. Hu proposes to integrate research and education in an investigation of carbon cycling and ocean acidification in the Mission-Aransas Estuary in South Texas. This coastal system is strongly affected by changes in river flow between seasons and from year to year. The relationship of changing river flows to carbon cycling in estuaries is not well understood. This lack of understanding in turn contributes to uncertainty in estimating global estuarine carbon budgets. In addition, climate change and other human activities heavily influence riverine input into estuaries and the coastal ocean, which then affect biogeochemistry and metabolism in these environments. Despite the need for this information, long-term records that can help to address the change in the strength and directions of CO2 fluxes in these ecosystems are very rare. Using high-intensity field sampling and analysis of historical data, this project aims to improve understanding of carbon cycling in this estuary and in the coastal ocean in general. The results obtained from this study will also provide key information about the biogeochemical response of estuaries to changing hydrologic conditions, as the southwestern U.S. grows drier with overall declining precipitation.The research objectives of this project include 1) investigating the relationship between hydrologic state and estuarine CO2 partial pressure (pCO2) in a case study of the Mission-Aransas Estuary, a subtropical semiarid estuary, 2) understanding the extent of CO2 flux and its hydrologic control in one of the world's largest lagoonal estuarine systems along the northwestern Gulf of Mexico, and 3) elucidating the mechanisms that lead to estuarine acidification and its feedback to CO2 fluxes. Intensive field campaigns for high-temporal resolution pCO2 and water carbonate chemistry sampling as well as sediment incubation will be carried out; analysis of multidecadal carbonate chemistry parameters that have been collected by Texas Commission on Environmental Quality will be used to obtain temporal trends of estuarine water pCO2 against the backdrop of increasing freshwater scarcity in this region. The education component of this CAREER award includes 1) creating an ocean and estuarine acidification research course and redesigning two existing courses for both undergraduate and graduate students, 2) collaborating with Foy Moody High School on their Aquatic Science education to engage high school students predominantly from underrepresented and economically challenged backgrounds in field and lab experiences. The ultimate educational goal is to encourage high school students to follow a STEM path for their college education, and undergraduate STEM students to pursue graduate degrees. This will be a part of the concerted effort to enhance diversity in the future workforce by increasing the number of underrepresented graduates with bachelor's or higher degrees in the STEM fields. This project will train one Ph.D. student. High school students and undergraduate interns from underrepresented and economically challenged backgrounds will also be supported to participate in summer research. Broader dissemination of the project findings will include undergraduate student presentations at symposiums organized by both TAMU-CC and the Texas A&M University System, public seminars by both the graduate students and the principal investigator at various meetings organized by regional estuarine programs, presentations at national and international meetings, and publications in peer-reviewed journals.