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Collaborative Research: Impacts of surface ocean surfactant sources and transformations on their chemical composition and air-sea relevant properties

合作研究：海洋表层表面活性剂来源及其转化对其化学成分和海气相关特性的影响

基本信息

批准号：
2123368
负责人：
Amanda Frossard
金额：
$ 34.09万
依托单位：
University of Georgia Research Foundation Inc
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-10-01 至 2024-09-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2123368&HistoricalAwards=false
关键词：
Collaborative Research Impacts surface ocean

项目摘要

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).The surface microlayer (SML), the thin layer of water at the interface between the ocean and the atmosphere, controls the exchange of materials to and from the ocean. As a result, it can profoundly influence biogeochemical cycles and global climate. One type of chemical species that accumulates at this interface are surfactant molecules, which influence the surface tension of and the rate of material exchange at air-water interfaces. Biological and chemical production and degradation processes represent surfactant sources and removal pathways, but the relative importance of those processes for determining surfactant quantities and molecular composition remains unclear. Similarly, the relationship between surfactant molecule composition and surface tension at the air-water interface has not been established. As a result, their effects on material exchange at the interface cannot currently be predicted. This work will use measurements at sea, laboratory experiments, and high-resolution analyses to measure the chemical and physical characteristics of surfactants and their properties at the air-sea interface. An improved understanding of surfactant processes and surface ocean will benefit society by improving our understanding of the exchange of climate-relevant gases and particles. Two early career PIs will advance their established collaboration and gain further experience leading research projects and mentoring students. Students will receive valuable hands-on training in oceanographic field collections, state-of-the-science analytical techniques, data interpretation, and data dissemination. The results and methodologies from this work will be featured in courses at the University of Georgia and the University of Delaware and will be developed into content for K-12 students, enhancing infrastructure for education. This work includes the unique pairing of state-of-the-science measurements across time and spatial scales to assess the influence of oceanographic processes on surfactant chemical composition and physical air-sea relevant properties. SML and subsurface waters will be collected from estuarine, coastal ocean, and open ocean sites during high and low productivity conditions to establish surfactant molecular characteristics over a range of space, time, and ocean biological activity. The effects of light will be assessed via diurnal sampling efforts and laboratory experiments. Samples will be analyzed for their detailed chemical, biological, and physical characteristics. The surface tension of the SML is expected to be inversely correlated with the abundance of lipid-like compounds (low O content, high H/C ratios, e.g., sulfur-containing lipids) produced during periods of high biological activity. Prolonged exposure to light is hypothesized to result in photo-oxidation of surfactant compounds, higher abundances of oxygenated and lower molecular weight aliphatic compounds, and increased surface tension. Multivariate statistical approaches will be used to reveal a mechanistic understanding of the links between biological and photochemical processes and the resulting surfactant and SML chemical and physical characteristics. This new knowledge will represent a first step toward improved models of the air-sea exchange of climate relevant gases which currently have large uncertainties. It will inform future work on the exchange of volatile and aerosol organics with significant potential impacts for our understanding of the climate system.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.

该奖项全部或部分由2021年美国救援计划法案（公法117-2）资助。表面微层（SML），即海洋和大气界面处的薄层水，控制着物质进出海洋的交换。因此，它可以深刻地影响地球化学循环和全球气候。在该界面处积聚的一种类型的化学物质是表面活性剂分子，其影响空气-水界面处的表面张力和材料交换速率。生物和化学生产和降解过程代表表面活性剂来源和去除途径，但这些过程对确定表面活性剂数量和分子组成的相对重要性仍不清楚。类似地，表面活性剂分子组成与空气-水界面处的表面张力之间的关系尚未建立。因此，目前无法预测它们对界面处物质交换的影响。这项工作将利用海上测量、实验室实验和高分辨率分析来测量表面活性剂的化学和物理特性及其在海-气界面的特性。对表面活性剂过程和海洋表层的更好理解将通过提高我们对与气候相关的气体和颗粒交换的理解而造福社会。两个早期职业PI将推进他们建立的合作，并获得领导研究项目和指导学生的进一步经验。学生将在海洋学领域收集，国家的科学分析技术，数据解释和数据传播方面接受宝贵的实践培训。这项工作的结果和方法将在格鲁吉亚大学和特拉华州大学的课程中展示，并将开发成K-12学生的内容，加强教育基础设施。这项工作包括跨时间和空间尺度的科学测量的独特配对，以评估海洋过程对表面活性剂化学成分和物理海气相关特性的影响。在高和低生产力条件下，将从河口、沿海和开阔洋采集SML和次表层沃茨，以确定不同空间、时间和海洋生物活性范围内的表面活性剂分子特征。将通过昼夜采样工作和实验室实验评估光照的影响。将分析样品的详细化学、生物和物理特性。预期SML的表面张力与脂质样化合物（低O含量、高H/C比，例如，含硫脂质）在高生物活性期间产生。假设长时间暴露于光下会导致表面活性剂化合物的光氧化、含氧化合物和较低分子量脂肪族化合物的丰度较高以及表面张力增加。多元统计方法将用于揭示生物和光化学过程之间的联系，并由此产生的表面活性剂和SML的化学和物理特性的机械理解。这一新的知识将是改进目前具有很大不确定性的与气候有关的气体的海气交换模型的第一步。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。