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

• 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

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.

该奖项的全部或部分资金根据《2021 年美国救援计划法案》（公法 117-2）提供。表面微层 (SML)，即海洋与大气界面处的薄水层，控制着交换进出海洋的材料。因此，它可以深刻影响生物地球化学循环和全球气候。在该界面积聚的一种化学物质是表面活性剂分子，它影响空气-水界面的表面张力和物质交换速率。生物和化学生产和降解过程代表了表面活性剂来源和去除途径，但这些过程对于确定表面活性剂数量和分子组成的相对重要性仍不清楚。同样，表面活性剂分子组成与空气-水界面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。提高对表面活性剂过程和表面海洋的了解将通过提高我们对气候相关气体和颗粒交换的了解而造福社会。两位早期职业 PI 将推进他们已建立的合作，并获得领导研究项目和指导学生的更多经验。学生将接受海洋学实地采集、最先进的分析技术、数据解释和数据传播方面的宝贵实践培训。这项工作的结果和方法将在佐治亚大学和特拉华大学的课程中得到体现，并将开发成供 K-12 学生使用的内容，从而增强教育基础设施。这项工作包括跨时间和空间尺度的最新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空气-海洋相关特性的影响。将在高和低生产力条件下从河口、沿海海洋和公海地点收集 SML 和地下水，以建立一系列空间、时间和海洋生物活性的表面活性剂分子特征。光的影响将通过每日采样工作和实验室实验进行评估。将分析样品的详细化学、生物和物理特性。 SML 的表面张力预计与高生物活性期间产生的类脂化合物（低 O 含量、高 H/C 比，例如含硫脂质）的丰度呈负相关。据推测，长时间暴露在光下会导致表面活性剂化合物的光氧化、含氧和较低分子量脂肪族化合物的丰度增加以及表面张力的增加。多元统计方法将用于揭示生物和光化学过程之间联系的机械理解以及由此产生的表面活性剂和 SML 化学和物理特性。这一新知识将代表朝着改进目前具有很大不确定性的气候相关气体的海气交换模型迈出的第一步。它将为未来关于挥发性和气溶胶有机物交换的工作提供信息，对我们了解气候系统具有重大潜在影响。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Organic Signatures of Surfactants and Organic Molecules in Surface Microlayer and Subsurface Water of Delaware Bay

特拉华湾表面微层和地下水中表面活性剂和有机分子的有机特征

• DOI: 10.1021/acsearthspacechem.2c00220
• 发表时间: 2022-11-21
• 期刊: ACS Earth and Space Chemistry
• 影响因子: 3.4
• 作者: Tret C. Burdette;Rachel L Bramblett;Ariana Deegan;Nicole R. Coffey;A. Wozniak;A. Frossard
• 通讯作者: A. Frossard