RAPID: The effect of El Nino on delivery of organic carbon in the Santa Clara River, CA

RAPID：厄尔尼诺现象对加利福尼亚州圣克拉拉河有机碳输送的影响

• 批准号: 2401563
• 负责人: Ellen Druffel
• 金额: $ 11.95万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-12-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2401563&HistoricalAwards=false
• 关键词: RAPID; effect; El; Nino; delivery

El Niño–Southern Oscillation (ENSO) causes changes in winds and sea surface temperature over the tropical eastern Pacific Ocean. Typically, this results in above average rainfall in Southern California. This project aims to understand how high rainfall associated with ENSO influences the delivery of carbon from land to the ocean. Specifically, the scientists will evaluate whether a unique pool of aged carbon derived from eroded soils in the watershed is transported to the ocean during these events. Samples of particulate and sedimentary organic carbon will be collected from the Santa Clara River in California. The samples will be collected under different river flow conditions between December 2023 and April 2024. The chemical composition of these samples will be analyzed and compared to samples collected during previous ENSO and non-ENSO time periods. This unique set of samples will record whether there are differences in the amounts and sources of carbon delivered to the ocean under different river flow conditions. Results from this study will improve global and long-term estimates of carbon export from land to the ocean. This project will support an early career scientist and an undergraduate student at the University of California-Irvine, a Hispanic-serving institution.This study will examine the sources of organic carbon (OC) delivered to the coastal zone of Southern California during the upcoming El Niño event of 2023-24. The project will test the hypothesis that extreme precipitation in the Santa Clara River watershed mobilizes a unique pool of mineral-associated OC that differs from the OC that is mobilized during normal or low precipitation years. Previous studies have shown that the mineral-associated OC mobilized during the strong El Niño of 1997-98 had higher ∆14C and d13C values than the OC exported during low flow periods. The science team will collect particulate OC (POC) and sedimentary OC (SOC) samples from the Santa Clara River under different flow conditions during the 2023-2024 El Niño event. Radiocarbon (∆14C) and stable carbon isotope values (d13C) for bulk OC, and compound specific isotope analyses of n-alkanes will be measured. These data will be compared to data obtained during time periods when precipitation and river flow conditions varied (1997-98, 2002-03, 2021-22). This combination of isotope information will allow the scientists to estimate the relative contributions of organic matter derived from different sources as well as the contribution of eroded mineral associated OC to the sediments. The project will provide research and training opportunities for a postdoc and an undergraduate student at the University of California-Irvine (UCI), a Hispanic-serving institution. The postdoc will participate in the CLEAN Education Program (Climate, Literacy, Empowerment and iNquery) and design phenomenon–based science curricula for use in local high schools and undergraduate labs in the Earth System Science Department at UCI.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.

厄尔尼诺 - 南方振荡（ENSO）导致热带东部太平洋的风和海面温度的变化。通常，这导致南加州的降雨量高于平均水平。该项目旨在了解与ENSO相关的降雨量如何影响从土地到海洋的碳输送。具体而言，科学家将评估在这些事件期间，从流域中侵蚀的土壤中衍生出的独特的老化碳池是否被运输到海洋。将从加利福尼亚的圣克拉拉河收集特定和沉积有机碳的样品。这些样品将在2023年12月至2024年4月之间在不同的河流条件下收集。这些样品的化学组成将进行分析，并将其与在以前的ENSO和非句子时间段内收集的样品进行比较。这组独特的样品将记录在不同河流条件下传递到海洋的碳的数量和来源差异。这项研究的结果将改善从土地到海洋的碳出口的全球和长期估计。该项目将支持早期的职业科学家和一名来自西班牙裔服务机构的加利福尼亚大学 - 艾尔文分校的本科生。这项研究将检查即将举行的2023 - 24年厄尔尼诺事件期间，有机碳（OC）的来源传递到南加州的沿海地区。该项目将检验以下假设：圣克拉拉河流域的极端降水动员了与矿物相关的OC的独特池，与在正常或低降水年内动员的OC不同。先前的研究表明，在1997 - 98年强的ElNiño中动员的矿物相关的OC具有高于科学团队的Δ14C和D13C值更高，而科学团队将在2023-2024 ElNiñuno事件中从不同流动条件下从不同流动条件下收集颗粒状OC（POC）和沉积OC（SOC）。用于散装OC的放射性碳（∆14C）和稳定的碳同位素值（D13C），将测量N-烷烃的复合特异性同位素分析。这些数据将与在降水量和河流流动条件变化时获得的数据进行比较（1997-98，2002-03，2021-22）。同位素信息的这种组合将使科学家能够估算从不同来源得出的有机物的相对贡献，以及发射矿物相关的OC对沉积物的贡献。该项目将为博士后和本科生提供加州大学西班牙裔服务机构的研究和培训机会。博士后将参加清洁教育计划（气候，识字，授权和询问）以及基于设计现象的科学课程，用于在UCI的地球系统科学系中用于当地的高中和本科实验室。该奖项反映了NSF的法定任务，并以基础的智力评估来进行评估，以评估良好的评估和广泛的效果。