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Atmospheric oxidation capacity sustained by a tropical forest.

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اقرأ على الانترنت اقرأ أكثر حفظ في قائمتي
  • معلومة اضافية
    • المصدر:
      Publisher: Nature Publishing Group Country of Publication: England NLM ID: 0410462 Publication Model: Print Cited Medium: Internet ISSN: 1476-4687 (Electronic) Linking ISSN: 00280836 NLM ISO Abbreviation: Nature Subsets: MEDLINE
    • بيانات النشر:
      Publication: Basingstoke : Nature Publishing Group
      Original Publication: London, Macmillan Journals ltd.
    • الموضوع:
      Tropical Climate*; Atmosphere/*chemistry ; Trees/*metabolism; Animals ; Atlantic Ocean ; Butadienes/metabolism ; French Guiana ; Guyana ; Hemiterpenes/metabolism ; Hydroxyl Radical/metabolism ; Nitric Oxide/metabolism ; Oxidation-Reduction ; Ozone/analysis ; Pentanes/metabolism ; Suriname
    • نبذة مختصرة :
      Terrestrial vegetation, especially tropical rain forest, releases vast quantities of volatile organic compounds (VOCs) to the atmosphere, which are removed by oxidation reactions and deposition of reaction products. The oxidation is mainly initiated by hydroxyl radicals (OH), primarily formed through the photodissociation of ozone. Previously it was thought that, in unpolluted air, biogenic VOCs deplete OH and reduce the atmospheric oxidation capacity. Conversely, in polluted air VOC oxidation leads to noxious oxidant build-up by the catalytic action of nitrogen oxides (NO(x) = NO + NO2). Here we report aircraft measurements of atmospheric trace gases performed over the pristine Amazon forest. Our data reveal unexpectedly high OH concentrations. We propose that natural VOC oxidation, notably of isoprene, recycles OH efficiently in low-NO(x) air through reactions of organic peroxy radicals. Computations with an atmospheric chemistry model and the results of laboratory experiments suggest that an OH recycling efficiency of 40-80 per cent in isoprene oxidation may be able to explain the high OH levels we observed in the field. Although further laboratory studies are necessary to explore the chemical mechanism responsible for OH recycling in more detail, our results demonstrate that the biosphere maintains a remarkable balance with the atmospheric environment.
    • Comments:
      Comment in: Nature. 2008 Apr 10;452(7188):701-2. doi: 10.1038/452701a. (PMID: 18401395)
    • الرقم المعرف:
      0 (Butadienes)
      0 (Hemiterpenes)
      0 (Pentanes)
      0A62964IBU (isoprene)
      31C4KY9ESH (Nitric Oxide)
      3352-57-6 (Hydroxyl Radical)
      66H7ZZK23N (Ozone)
    • الموضوع:
      Date Created: 20080411 Date Completed: 20080514 Latest Revision: 20131121
    • الموضوع:
      20250114
    • الرقم المعرف:
      10.1038/nature06870
    • الرقم المعرف:
      18401407