The role of organic and metal cofactors on the biogenic synthesis of halogenated volatile hydrocarbons

有机和金属辅助因子对卤代挥发性烃生物合成的作用

• 批准号: 1559276
• 负责人: Sergio Sanudo-Wilhelmy
• 金额: $ 68.1万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2020-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1559276&HistoricalAwards=false
• 关键词: role; organic; metal; cofactors; biogenic

Volatile halogenated hydrocarbon gases, in this case halomethanes, are produced naturally by organisms in the ocean; which then serves as a source of these biogenic gases to the atmosphere. Their chemical reactions in the atmosphere are very similar to those of anthropogenic chlorofluorocarbons (CFCs). While CFCs are well-studied because they consume the ozone in the upper atmosphere that shields the earth from harmful ultraviolet radiation, halomethanes have been largely neglected, even though they currently account for 25% of the ozone depletion. As anthropogenic CFC levels steadily decline, however, halomethanes are predicted to account for 50% of ozone depletion by 2050. Based on limited study thus far, marine halomethane production has been ascribed mainly to phytoplankton and macro algae. This project will build on new and compelling data that suggests marine heterotrophic bacteria could also be major producers of halomethanes. The data produced here will provide the critical evaluation required to address discrepancies in global halomethane budgets which currently are out of balance due to an unknown source to the atmosphere, evaluating the hypothesis that marine heterotrophic bacteria can supply this missing source. Concerns over the stability of the earth's stratospheric ozone layer make this valuable and necessary research with added value of providing support for engaged undergraduate, graduate, and postdoctoral education at the University of Southern California.Past research on the production of marine halomethanes has focused on phytoplankton and macro algae, while potential bacterial contributions to the processe have been neglected. This research proposes to study the role of marine heterotrophic bacteria on the production of halomethanes. It has been noted in past studies that there are discrepancies in the global atmospheric halomethane budget, and it is possible this is due to a large missing bacterial source. Additionally, this research will evaluate the potential importance of vitamin B12, methionine, and vanadium cofactors on the synthesis of halomethanes in bacteria. A large portion of marine bacteria cannot synthesize methylation co-enzymes, and therefore, would require available B12, methionine, and vanadium from external sources to complete the methylation step. This study will also measure concentrations of halomethanes, B12, methionine, and vanadium in upwelling regions as well as at a long-term time series site in order to put constraints on the variability of halomethanes concentrations for use in global linked air-sea models.

挥发性卤代烃气体，在这种情况下是光甲人们的，是由海洋中的生物自然产生的。然后，这是这些生物气体到大气中的来源。它们在大气中的化学反应与人为的氯氟化碳（CFC）非常相似。尽管CFC经过了充分的研究，因为它们在上层大气中消耗了臭氧，从而使地球免受有害的紫外线辐射，但卤素甲基被大大忽略了，尽管它们目前占臭氧耗竭的25％。 然而，随着人为CFC的水平稳步下降，预计到2050年，卤代甲烷将占臭氧耗竭的50％。基于迄今为止的有限研究，海洋卤代甲烷的产量主要归因于浮游植物和宏观藻类。该项目将建立在新的和引人入胜的数据的基础上，这表明海洋异养细菌也可能是卤素甲烷的主要生产国。 此处产生的数据将提供解决全球卤甲烷预算中差异所需的关键评估，该预算由于大气的未知来源而无法平衡，评估了海洋异质营养细菌可以提供这种缺失的来源的假设。人们对地球平流层臭氧层层的稳定性的担忧使得这项有价值和必要的研究具有为南加州大学提供支持的本科，毕业生和博士后教育提供支持的价值。对生产海洋卤素的研究的研究重点是植物素的生产，同时又涉及浮游植物的细菌，同时又有了细菌的贡献。这项研究建议研究海洋异养细菌对卤甲烷产生的作用。在过去的研究中已经指出，全球大气卤代预算中存在差异，这可能是由于大量缺失的细菌来源所致。此外，这项研究将评估维生素B12，蛋氨酸和钒辅助因子对细菌中卤代盐的合成的潜在重要性。很大一部分海洋细菌不能合成甲基化共酶，因此，外部来源需要可用的B12，甲硫氨酸和钒才能完成甲基化步骤。这项研究还将测量上升区域以及长期时间序列位置中的盐酸盐，B12，蛋氨酸和钒的浓度，以对全球链接空气模型的使用量构成限制。