RUI: Polyhalomethanes in Marine Waters: The Role of DOC and Extracellular Bromoperoxidase

RUI：海水中的多卤甲烷：DOC 和细胞外溴过氧化物酶的作用

• 批准号: 0350746
• 负责人: Steven Manley
• 金额: --
• 依托单位: California State University-Long Beach Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-05-01 至 2009-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0350746&HistoricalAwards=false
• 关键词: RUI; Polyhalomethanes; Marine; Waters; Role

ABSTRACTOCE-0350746Polyhalomethanes produced by marine algae, supply reactive bromine and iodine atoms to the atmosphere where they promote the destruction of both tropospheric and stratospheric ozone, and in the case of iodomethanes, promote the formation of marine aerosols. Polyhalomethanes are indirect products of marine algal haloperoxidase activity, formed as a consequence to destroy toxic H2O2 produced both within and outside their cells.Looking to link algal physiology, marine chemistry and atmospheric science, researchers at the California State University at Long Beach will demonstrate that marine DOC can form polybromo- and polyiodo- methanes catalyzed by algal extracellular bromoperoxidases (BrPO). Measurement of polyhalomethane production will be quantified using a GC-ECD; GC-MS will confirm peak identity. The active DOC fraction(s) will be characterized by their MW size class, using stirred N2-pressurized ultrafiltration. Seawater collected from different coastal locations during the summer and winter will be used to ensure differences in DOC quantity and quality, and will be analyzed for salinity, DOC (high temperature combustion technique) and H2O2 (fluorometric assay). Polybromomethane production from DOC (i.e. ng CHBr3 - biomass-1) by a seaweed and diatom species will be determined from measuring the number of BrPO units present on their surfaces (spectrophotometric assay) and from measuring the rate of polybromomethane production from DOC per commercial BrPO units (similarly defined). Other experiments will directly contrast total polyhalomethane production from these species in seawater of known DOC concentration, to production in seawater in which the DOC has been removed. Comparison of results from these two different methods will allow for the assessment of the significance of this process. This biologically mediated transformation of DOC to polyhalomethanes, which is eventually lost to the atmosphere, is a unique biogeochemical process. Unlike the extracellular enzymes of heterotrophic bacteria that degrade DOC as a source of nutrition (with the production of respiratory CO2), marine algae do not derive any nutritional benefit from the halogenation of DOC and may compete with certain bacteria for the same compounds.

由海藻产生的多卤甲烷向大气提供活性溴和碘原子，在大气中它们促进对流层和平流层臭氧的破坏，并且在碘甲烷的情况下，促进海洋气溶胶的形成。多卤甲烷是海藻卤过氧化物酶活性的间接产物，其形成是为了破坏其细胞内外产生的有毒H2 O2。长滩的加州州立大学的研究人员希望将藻类生理学、海洋化学和大气科学联系起来，他们将证明海洋DOC可以在藻类细胞外溴过氧化物酶（BrPO）催化下形成多溴甲烷和多碘甲烷。将使用GC-ECD定量测定多卤甲烷的产量; GC-MS将确证峰的同一性。活性DOC级分将通过其MW尺寸类别进行表征，使用搅拌N2加压超滤。夏季和冬季从不同沿海地区收集的海水将用于确保DOC数量和质量的差异，并将分析盐度，DOC（高温燃烧技术）和H2 O2（荧光测定）。通过测量海藻和硅藻表面存在的BrPO单位数量（分光光度测定法）和测量每商业BrPO单位DOC的多溴甲烷生产率（定义类似），确定海藻和硅藻物种从DOC产生的多溴甲烷（即ng CHBr 3-生物量-1）。其他实验将直接对比这些物种在已知DOC浓度的海水中的多卤甲烷总产量与DOC已被去除的海水中的产量。比较这两种不同方法的结果将有助于评估这一过程的重要性。这种生物介导的DOC转化为多卤甲烷，最终损失到大气中，是一个独特的地球化学过程。与异养细菌的胞外酶降解DOC作为营养源（产生呼吸CO2）不同，海藻不从DOC的卤化中获得任何营养益处，并且可能与某些细菌竞争相同的化合物。