Photochemical Formation of Carbon Dioxide from Dissolved Organic Matter: A New Approach to Constraining a Major Term in Marine Carbon Cycling

溶解有机物光化学形成二氧化碳：限制海洋碳循环主要术语的新方法

• 批准号: 0223200
• 负责人: Oliver Zafiriou
• 金额: --
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0223200&HistoricalAwards=false
• 关键词: Photochemical; Formation; Carbon; Dioxide; Dissolved

ABSTRACTOCE-0223200Recent discoveries have shown that photoxidation of colored dissolved organic matter (CDOM) also lead to the formation of dissolved inorganic carbon (DIC) or photo-CO2. Fluxes of photo-CO2 are estimated to produce one to several gigatons of CO2-C per year globally. A PI from Woods Hole Oceanographic Institution proposes to constrain photo-CO2 production using the Pool Isotopic Exchange (PIE) method, a technique which does not require perturbing the sample as occurs in currently available methods (i.e., changing pH, removing carbonate system, bubbling of sample). In the PIE method, the DI12C pool in seawater is replaced via exchange with DI13CO2 during incubation of the samples; thus, the DI12C pool which dilutes the newly formed 12CO2 (DI12C) from dissolved organic carbon (DOC) is minimized without major perturbations of the physical and chemical properties of the sample. The rates of formation of DI12C as a result of photoxidation will be measured by isotope ratio mass spectrometry (IRMS). The objectives of the proposal are to develop, test and optimize the PIE approach both in the laboratory and in the field. In addition, the PI will apply the PIE method and compare his results with those obtained by a collaborator from the State University of New York, Stony Brook using the Pool Depletion (PD) technique on the same samples recovered from waters enriched in CDOM. Lastly, the PI plans to resolve any potential discrepancies obtained via the PIE and PD methods.

最近的发现表明，有色溶解有机物（CDOM）的光氧化也会导致溶解无机碳（DIC）或光CO2的形成。 据估计，光-CO2通量每年在全球产生1至几千兆吨的CO2-C。 来自伍兹霍尔海洋研究所的PI建议使用池同位素交换（PIE）方法来限制光CO2的产生，该方法不需要像当前可用的方法中那样扰动样品（即，改变pH、除去碳酸盐体系、样品鼓泡）。 在PIE方法中，海水中的DI 12 C池在样品孵育期间通过与DI 13 CO2的交换而被替换;因此，稀释溶解有机碳（DOC）中新形成的12 CO2（DI 12 C）的DI 12 C池被最小化，而不会对样品的物理和化学性质产生重大干扰。 将通过同位素比质谱法（IRMS）测量光氧化导致的DI 12 C形成速率。 该提案的目标是在实验室和现场开发、测试和优化PIE方法。 此外，PI将应用PIE方法，并将其结果与斯托尼布鲁克纽约州立大学的合作者使用池耗尽（PD）技术从富含CDOM的沃茨中回收的相同样品获得的结果进行比较。 最后，PI计划解决通过PIE和PD方法获得的任何潜在差异。