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.

亚马逊河是最大的淡水和碳，因此，亚马逊河的淡水界限对于理解亚马逊河和接收大西洋的速度很重要。在热带和亚热带中，热带地区的风温度变化，以及和和和和和。 2024年2月。这项事件导致降水量和空气温度ASIN和从亚马逊河的淡水交付。事件。23夏季，该研究将在此期间和之后确定科学家团队，将有机碳带到沿海地区。在美国的联合会的研究人员和巴西的搜索者之间受到了不断变化的亚马逊河的影响最近的研究假设了即将举行的2023年厄尔尼诺事件，与非埃森（Non-Enso）和拉尼娜（LaNiña）年相比，亚马逊河的出口试验的年度通量和出口试验的比例。例如，在厄尔尼诺（Elniño）的铅和分子级成分中，ft-iCr MS将在跨亚马逊贝斯（Amazon Bassin）和头上的响应中更改。从2011-2012LaNiña年和随后的2012-2013水力学上正常的年份对DOM采样的详细表征（FT-ICR MS，光学，荧光分析）导出到海洋系统，并为UDIE创建一个框架，以调查ENSO如何影响出排放和碳的出口，并从其他主要的热带 - 热带河流中出口，并最终影响全球陆地碳的出口。通过评估使用智力的优点和更广泛的影响标准来支持。