RUI: Collaborative Research: Cycling of ethanol and acetaldyhyde in coastal waters

RUI：合作研究：乙醇和乙醛在沿海水域的循环

• 批准号: 2022112
• 负责人: Warren De Bruyn
• 金额: $ 21.76万
• 依托单位: Chapman University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2022112&HistoricalAwards=false
• 关键词: RUI; Collaborative; Research; Cycling; ethanol

Ethanol is added to gasoline to increase octane levels and lower the concentrations of carbon monoxide and surface ozone in the atmosphere. As a renewable fuel, ethanol may also help decrease our dependence on gasoline. Increased use of ethanol in the United States and globally as a fossil fuel substitute and additive is expected to increase ethanol levels in the atmosphere. Atmospheric ethanol is converted to acetaldehyde which is a hazardous pollutant. To understand the impact of increasing ethanol usage, it is important to understand the cycling of ethanol and acetaldehyde in the environment--how they are produced, consumed, and interconverted. Because these compounds can cross from air into water, this requires understanding what happens to these compounds in both the atmosphere and in seawater and other surface waters. This proposal focuses on improving our understanding of processes that produce and consume ethanol and acetaldehyde in coastal seawater and other coastal surface waters like estuaries and salt marshes. This project will measure the rates of photochemical production of ethanol and acetaldehyde, as well as their chemical and biological degradation rates. The project will also measure the rate and efficiency of the biological production of acetaldehyde from ethanol by microbial organisms in these waters. The scientists have an excellent track record of involving undergraduate students, including underrepresented minorities, in their research and as co-authors on publications, a trend they plan to continue with this project. These students would be trained in analytical chemistry and environmental research and would present their research findings at local and national conferences. Lastly, the PIs also plan outreach activities with high school STEM programs to improve student diversity in environmental research.The primary sink for ethanol in the troposphere is reaction with OH to produce acetaldehyde. Acetaldehyde levels in the troposphere are also expected to increase with increased use of ethanol. Changes in the atmospheric concentrations of these species are expected to have a significant impact on the oxidative capacity of the troposphere. To understand future impacts, it is important to understand current tropospheric budgets which have significant uncertainties for both species. One of the largest sources of uncertainty is the role of the oceans and surface waters in cycling these species into and out of the troposphere. The current understanding is limited by the very small database of ambient concentration measurements in both air and water and an incomplete insight into the processes that control concentrations in seawater and surface waters; these processes represent a complex interplay between biological and photochemical sources and sinks, and air-water exchange. To improve the current understanding of the cycling of ethanol and acetaldehyde in coastal seawater and surface waters, this project will measure: 1) chemical and biological degradation rates of ethanol and acetaldehyde in coastal waters; 2) the rate and efficiency of the biological production of acetaldehyde from ethanol by microbial organisms; 3) ethanol and acetaldehyde concentrations in air and surface waters; 4) the ethanol and acetaldehyde source strength of estuary and saltmarsh sediments; and 5) ethanol and acetaldehyde photochemical production rates in surface waters.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.

将乙醇添加到汽油中以增加辛烷值水平，并降低一氧化碳和大气中表面臭氧的浓度。 作为可再生燃料，乙醇也可能有助于减少我们对汽油的依赖。 在美国和全球作为化石燃料替代品和添加剂的使用增加将增加大气中的乙醇水平。 大气乙醇被转化为乙醛，这是一种危险污染物。 要了解增加乙醇使用情况的影响，重要的是要了解环境中乙醇和乙醛的循环 - 它们是如何生产，消耗和相互交流的。因为这些化合物可以从空气跨入水，所以这需要了解大气，海水和其他地表水中这些化合物的情况。该提案的重点是提高我们对沿海海水和其他沿海地面水（如河口和盐沼泽）中生产和消费乙醇和乙醛的过程的理解。该项目将衡量乙醇和乙醛的光化学产生速率，以及它们的化学和生物降解速率。该项目还将衡量这些水中微生物从乙醇中乙醇生物生产的速率和效率。 科学家在研究研究和作为出版物的合着者中，包括少数群体在内的本科生（包括代表性不足的少数民族）的良好记录，他们计划继续进行该项目。 这些学生将接受分析化学和环境研究的培训，并将在当地和民族会议上介绍他们的研究结果。 最后，PIS还计划使用高中STEM计划的外展活动，以改善学生在环境研究中的多样性。对流层中乙醇的主要水槽与OH的反应是产生乙醛。预计，由于使用乙醇的使用增加，对流层中的乙醛水平也会增加。 这些物种的大气浓度的变化预计将对对流层的氧化能力产生重大影响。要了解未来的影响，重要的是要了解当前对这两种物种都有明显不确定性的对流层预算。不确定性的最大来源之一是海洋和地表水在将这些物种循环进入对流层中的作用。当前的理解受到空气和水中环境浓度测量的非常小的数据库的限制，以及对控制海水和地表水中浓度的过程的不完全见解。这些过程代表了生物学和光化学源和水槽以及空气水交换之间的复杂相互作用。 为了提高沿海海水和地表水中乙醇和乙醛循环的当前理解，该项目将衡量：1）沿海水域乙醇和乙醛的化学和生物降解速率； 2）微生物生物体从乙醇中乙醛生物产生的速率和效率； 3）空气和地表水中的乙醇和乙醛浓度； 4）河口和盐泥沉积物的乙醇和乙醛源强度； 5）地表水中的乙醇和乙醛光化学生产率。该奖项反映了NSF的法定任务，并且使用基金会的知识分子优点和更广泛的影响审查标准，被认为值得通过评估来获得支持。