Low Molecular Weight Carbonyls in Seawater: Formation Via Photochemical Processes and Role in the Chemistry of Humic Substances

海水中的低分子量羰基：通过光化学过程形成及其在腐殖质化学中的作用

• 批准号: 9315821
• 负责人: Kenneth Mopper
• 金额: --
• 依托单位: Washington State University
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-12-01 至 1997-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9315821&HistoricalAwards=false
• 关键词: Low; Molecular; Weight; Carbonyls; Seawater

9315821 MOPPER Light-initiated reactions play important roles in chemical and biological processes in the sea, including redox reactions, carbon cycling and photoinhibition. Despite the importance of photochemical processes, almost nothing is known about photochemical pathways and reaction sites within marine DOM that are responsible for production of reactive sites within Marine DOM that are responsible for production of reactive transients at the sea surface. The focus will be shifted from oceanic carbon cycling to the study of precursors and mechanisms involved in the photochemical formation of LMW carbonyl compounds and OH radicals form marine DOM and DOM isolates, e.g., humic substances. Some of the key questions are: Are LMW carbonyl compounds and OH radicals formed mainly by primary or by secondary photoprocesses? What is the role of oxidants, e.g., O2, superoxide peroxides, in the photoproduction of these species in seawater? Is photobleaching of DOM fluorescence (and absorbance) in seawater accompanied by an actual loss of humic substances or only of chromophoric moieties? Can the marine DOM pool be physically fractionated into photoreactive (humic) and photo-unreactive fractions? What is the nature of the chromophoric sites within marine DOM? This study will provide new basic information on the photochemical, chemical, and spectroscopic properties of marine DOM.

小行星9315821 光引发的反应在海洋化学和生物过程中起着重要的作用，包括氧化还原反应、碳循环和光抑制。 尽管光化学过程的重要性，几乎没有什么是已知的光化学途径和海洋DOM内的反应位点，负责生产海洋DOM内的反应位点，负责生产反应瞬变在海面上。 重点将从海洋碳循环转向研究海洋DOM和DOM分离物中低分子量羰基化合物和OH自由基光化学形成的前体和机制，例如，腐殖物质 一些关键的问题是：低分子量羰基化合物和OH自由基形成主要由初级或次级光过程？氧化剂的作用是什么，例如，O2，超氧化物过氧化物，在这些物种在海水中的光生产？ 海水中DOM荧光（和吸光度）的光漂白是否伴随着腐殖物质的实际损失或仅发色基团的损失？ 海洋DOM池能否物理分离为光反应（腐殖酸）和光不反应部分？海洋DOM中发色位点的性质是什么？这项研究将提供新的海洋DOM的光化学，化学和光谱特性的基础信息。