概括
全球二氧化 (N2O) 预算失衡. 土壤的排放量在同位素上很轻,需要一个沉重的N2O来源,可能来自平流层或海洋,以平衡预算.
科学领域:
- 地球系统科学 地球系统科学
- 大气化学 大气化学
- 同位素地球化学 同位素地球化学
背景情况:
- 全球氧化 (N2O) 预算显示,平流层破坏与土壤和海洋估计产生的产量之间存在重大不平衡.
- 热带气体N2O来源,包括热带雨林和受肥土壤,释放的N2O耗尽在重同位素 (15N和18O).
研究的目的:
- 为了研究主要的陆地来源的N2O的同位素组成.
- 为了确定全球预算平衡所需的缺失的N2O来源.
- 了解极地冰芯对同位素变化的影响.
主要方法:
- 在热层N2O样本中测量15N/14N和18O/16O比率.
- 从热带雨林土壤 (哥斯达黎加) 和受肥农业土壤 (毛伊岛) 中分析N2O.
- 建模同位素流量以平衡全球N2O预算.
主要成果:
- 来自热带雨林和受肥田地的土壤衍生N2O与平均热带N2O相比,在15N和18O中显著减少.
- 需要大量的同位素重N2O来源,富含15N和18O,以平衡土壤中轻量的N2O.
- 由于光分解而富含重同位素的平流层N2O,以及潜在的大型海洋流,是这种平衡源的候选者.
结论:
- 土壤N2O的同位素特征表明全球预算存在重大不平衡.
- 高层层和海洋流在通过重同位素丰富来平衡全球N2O预算方面发挥着至关重要的作用.
- 极地冰芯中N2O的同位素变化可以提供对过去N2O预算动态和气候相互作用的见解.
相关概念视频
Noble Gases
The elements in group 18 are noble gases (helium, neon, argon, krypton, xenon, and radon). They earned the name “noble” because they were assumed to be nonreactive since they have filled valence shells. In 1962, Dr. Neil Bartlett at the University of British Columbia proved this assumption to be false.
The Equilibrium Constant
Consider the oxidation of sulfur dioxide:
Other Nuclides: 31P, 19F, 15N NMR
Many organic, inorganic, and biological molecules contain spin-half nuclei such as nitrogen-15, fluorine-19, and phosphorus-31. As a result, NMR studies of these nuclei have found extensive applications in chemical and biological research.
While fluorine-19 and phosphorous-31 have high natural abundances (100%) and positive gyromagnetic ratios, nitrogen-15 has a low natural abundance and a negative gyromagnetic ratio. However, nitrogen-15 is still preferred over nitrogen-14 (which has a high...
While fluorine-19 and phosphorous-31 have high natural abundances (100%) and positive gyromagnetic ratios, nitrogen-15 has a low natural abundance and a negative gyromagnetic ratio. However, nitrogen-15 is still preferred over nitrogen-14 (which has a high...
Inhalational Anesthetics: Overview
Inhalation anesthetics are drugs that induce general anesthesia upon inhalation. They work by increasing the sensitivity of GABAA receptors or inhibiting NMDA receptors, leading to a decrease in central nervous system activity. The depth of anesthesia can be rapidly adjusted by changing the concentration of the inhaled gas. Some common examples of inhalational anesthetics include volatile liquids like isoflurane, desflurane, sevoflurane and gases like xenon and nitrous oxide. Isoflurane, a...
Exceptions to the Octet Rule
Many covalent molecules have central atoms that do not have eight electrons in their Lewis structures. These molecules fall into three categories:
The Nitrogen Cycle
Nitrogen atoms, present in all proteins and DNA, are recycled between abiotic and biotic components of the ecosystem. However, the primary form of nitrogen on Earth is nitrogen gas, which cannot be used by most animals and plants. Thus, nitrogen gas must first be converted into a usable form by nitrogen-fixing bacteria before it can be cycled through other living organisms. The use of nitrogen-containing fertilizers and animal waste products in human agriculture has greatly influenced the...


