RAPID: El Nino Event Impacts on Organic Matter Export and Composition in the Amazon River

RAPID：厄尔尼诺事件对亚马逊河有机物出口和成分的影响

• 批准号: 2333961
• 负责人: Robert Spencer
• 金额: $ 9.88万
• 依托单位: Florida State University
• 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: 2023-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2333961&HistoricalAwards=false
• 关键词: RAPID; El; Nino; Event; Impacts

The Amazon River is one of the largest sources of freshwater and carbon to the ocean. Thus, understanding the factors that influence freshwater delivery from the Amazon River is important for understanding the carbon cycle of the Amazon River and the receiving Atlantic Ocean. El Niño–Southern Oscillation (ENSO) is a periodic event that causes changes in winds and sea surface temperature over the tropical eastern Pacific Ocean and affects climate in the tropics and subtropics. The National Weather Service predicts that El Niño conditions are likely to form across the Pacific during Summer 2023. These conditions are expected to last through February 2024. This event is expected to impact precipitation and air temperatures in the Amazon Basin and freshwater delivery from the Amazon River. This project aims to study the amount and chemical composition of dissolved organic carbon delivered from the Amazon River to the Atlantic Ocean during the 2023-2024 El Niño event. Scientists involved in this project plan to collect samples from late Summer 2023 through late Summer 2024. The study will identify conditions before, during and after this event. This unique set of samples will enable the team of scientists to study how ENSO influences the delivery of organic carbon to the coastal ocean. This project provides support for an early career researcher and promotes international cooperation and inclusivity between researchers from the United States of America and researchers in Brazil who are directly impacted by the changing Amazon River. This project examines how El Niño Southern Oscillation (ENSO) anomalies impact the export of dissolved organic carbon (DOC) and composition of dissolved organic matter (DOM) from the Amazon River to the Atlantic Ocean. Based on recent studies, it has been hypothesized that the upcoming 2023 El Niño event will reduce the annual DOC flux and proportion of exported terrestrial DOM from the Amazon River compared to non-ENSO and La Niña years. This hypothesis will be examined by linking established state-of-the-art optical and molecular-level characterization techniques (e.g., Fourier-transform ion cyclotron resonance mass spectrometry; FT-ICR MS) with DOC flux calculations over the course of an El Niño year. Analyzing both bulk DOC fluxes and the molecular-level composition will reveal how the quantity and quality of DOM export will change monthly in response to reduced precipitation and higher temperature across the Amazon Basin and headwaters. DOC fluxes as well as detailed characterizations (FT-ICR MS, optical, fluorescence analysis) of DOM sampled from the furthest downstream Amazon River gauging station at Óbidos (Brazil) will be directly compared to results obtained from the 2011-2012 La Niña year and the following 2012-2013 hydrologically normal year to determine how global climate anomalies impact the DOC export to marine systems and to create a framework for future predictions. Data obtained from this proposed study will lay the foundations for larger studies investigating how ENSO cycles impact discharge and carbon export from other major tropical-subtropical rivers and ultimately, how ENSO cycles impact global land-ocean carbon export.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.

亚马逊河是淡水和海洋碳的最大来源之一。这是理解影响从亚马逊河分娩的因素对于了解亚马逊河和接收大西洋的碳周期很重要。厄尔尼诺尼诺 - 西南振荡（ENSO）是一个周期性的事件，会导致热带东部太平洋的风和海面温度的变化，并影响热带和热带东部太平洋的气候，并影响热带和热带海洋和热带海洋和亚物种的热带气候。国家气象局预测，厄尔尼诺现象可能会在2023年夏季在整个太平洋地区形成。预计这些条件将持续到2024年2月。预计该事件将影响亚马逊盆地的降水和气温和从亚马逊河的淡水交付。该项目旨在研究2023 - 2024年ElNiño活动期间从亚马逊河到大西洋传递的溶解有机碳的数量和化学成分。参与该项目的科学家计划从2023年夏末至2024年夏末收集样品。该研究将在此事件之前，期间和之后确定条件。这组独特的样本将使科学家团队能够研究ENSO如何影响有机碳向沿海海洋传递。该项目为早期的职业研究人员提供了支持，并促进了美利坚合众国研究人员与巴西研究人员之间的国际合作和包容性，这些研究人员直接受到不断变化的亚马逊河的影响。该项目考试厄尔尼诺南部振荡（ENSO）如何影响溶解有机碳（DOC）的出口以及从亚马逊河到大西洋的溶解有机物（DOM）的组成。根据最近的研究，已经假设即将到来的2023年厄尔尼诺事件将减少亚马逊河的年度DOC通量和与非埃森和拉尼娜时代相比，亚马逊河的出口陆地DOM的比例。将通过将已建立的最先进的光学和分子级特征技术（例如，傅立叶转换离子转基因共振质谱法； ​​FT-ICR MS）与doc通量计算的计算联系起来，来研究这一假设。分析批量DOC通量和分子水平的组成将揭示DOM出口的数量和质量如何随着亚马逊盆地和源水流的降水量降低和较高的温度而变化。 DOC通量和详细字符（FT-ICR MS，光学，荧光分析）从最远的下游亚马逊河仪表站（Brazil）取样的DOM将与2011-至2012年LaIniña年的结果以及在2012-2013-2013-2013-2013-2012 - 2013年的范围中获得的结果直接进行比较。未来的预测。 Data obtained from this proposed study will lay the foundations for larger studies investigating how ENSO cycles impact discharge and carbon export from other major tropical-subtropical rivers and ultimately, how ENSO cycles impact global land-ocean carbon export.This award reflects NSF's statutory mission and has been deemed honestly of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.