Transient tracer

  • 文章类型: Journal Article
    钚,以及137Cs等裂变产物,1945年,在新墨西哥州沙漠中p炸弹的第一次大气核爆炸后被释放到地球环境中(美国,7月16日)和后来的长崎(8月9日),随后发生了许多其他爆炸。因此,由于钚的放射性和化学毒性,钚在大气和海洋中的循环已成为公众关注的主要问题。然而,钚同位素和137Cs是环境中生物地球化学和物理过程的重要瞬时示踪剂,分别。在这次审查中,我们表明,需要物理和化学方法来全面了解大气和海洋中钚的行为。在大气中,钚和137Cs附着在气溶胶上;因此,钚根据与气溶胶相关的物理和化学过程移动;然而,因为钚是一种化学反应元素,它在水性环境中的行为更加复杂,因为生物地球化学调节因素,除了地球物理调控因素,必须考虑。同时,137Cs在水性环境中是化学惰性的。因此,钚的生物地球化学特征可以通过与137Cs的生物地球化学特征进行比较来阐明,它们显示出保守的特性,并根据物理过程移动。最后,我们建议对钚和137Cs进行监测可以帮助阐明气候变化引起的地球物理和生物地球化学变化。
    Plutonium, as well as fission products such as 137Cs, had been released into the earth environment in 1945 after the first atmospheric nuclear explosion of plutonium bomb in the desert of New Mexico (USA, July 16) and later over Nagasaki (August 9), followed then by many other explosions. Thus, plutonium cycling in the atmosphere and ocean has become a major public concern as a result of the radiological and chemical toxicity of plutonium. However, plutonium isotopes and 137Cs are important transient tracers of biogeochemical and physical processes in the environment, respectively. In this review, we show that both physical and chemical approaches are needed to comprehensively understand the behaviors of plutonium in the atmosphere and ocean. In the atmosphere, plutonium and 137Cs attach with aerosols; thus, plutonium moves according to physical and chemical processes in connection with aerosols; however, since plutonium is a chemically reactive element, its behavior in an aqueous environment is more complicated, because biogeochemical regulatory factors, in addition to geophysical regulatory factors, must be considered. Meanwhile, 137Cs is chemically inert in aqueous environments. Therefore, the biogeochemical characteristics of plutonium can be elucidated through a comparison with those of 137Cs, which show conservative properties and moves according to physical processes. Finally, we suggest that monitoring of both plutonium and 137Cs can help elucidate geophysical and biogeochemical changes from climate changes.
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  • 文章类型: Journal Article
    在这项研究中,我们基于示踪剂数据成功估计了微生物驱动的耗氧反应(微生物驱动)的表观活化能.结合Arrhenius/Eyring方程,采用表观化学反应速率常数的概念来估算与耗氧率相关的各种热力学参数。在南海和苏禄海的上层发现了80-90kJmol-1的正常Ea值,在快速通风的地中海中观察到更高的Ea值(300-1000kJmol-1),日本海,和温度较低的白令海。我们将典型海盆的特征分为四类。系统地计算了每个海洋区域中与温度相关的耗氧率关系,以得出各自的热力学特征值。这使我们能够将速率-温度关系参数化为热力学量,能够更有效地将不同海域的不同流域特征整合到海洋生化模型中。参数化有助于对温度、耗氧率。
    In this study, we successfully estimated the apparent activation energy of a microbially driven oxygen-consuming reaction (microbial-driven) based on tracer data. The concept of the apparent chemical reaction rate constant was employed to estimate various thermodynamic parameters associated with the oxygen consumption rate in conjunction with Arrhenius/Eyring equations. Normal Ea values of 80-90 kJ mol-1 were found in the upper layers of the South China Sea and Sulu Sea, while higher Ea values (300-1000 kJ mol-1) were observed in the rapidly ventilated Mediterranean Sea, the Sea of Japan, and the Bering Sea with lower temperatures. We classified the characteristics of typical sea basins into four categories. The temperature-dependent oxygen consumption rate relationship in each marine region was systematically calculated to derive the respective thermodynamic characteristic values. This allowed us to parameterize the rate-temperature relationship into thermodynamic quantities, enabling more effective integration of distinct basin characteristics within different sea areas into the marine biochemical model. Parameterization facilitates relatively accurate prediction of changes such as temperature, oxygen consumption rate.
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  • 文章类型: Journal Article
    全球气候变化是一个不争的事实,人为干扰是可能的驱动机制;此外,边缘海往往比全球海洋反应更快。在这项研究中,运输时间分布方法用于估算北太平洋和北冰洋西侧典型边缘海中的人为碳(Cant)。从南海(SCS)到北冰洋(AO),Cant的存储范围随着纬度的增加而逐渐增加。在AO和SCS中观察到〜0.6molC·m-2·yr-1和〜0.2molC·m-2·yr-1的最大和最小速率,分别。在短期内,冰盖的变暖和下降可能会促进过量的二氧化碳从大气中转移到水内部;但在更长的时间尺度上,积极的反馈(即,减少CO2吸收)可能由于变暖而发生。因此,当海冰完全消失时,AO将来可能不再是二氧化碳汇。
    Global climate change is an indisputable fact, and anthropogenic disturbances are the likely driving mechanisms; moreover, marginal seas tend to respond faster than the global ocean. In this study, the transit time distribution method was used to estimate the anthropogenic carbon (Cant) in the typical marginal seas along the west side of North Pacific Ocean and the Arctic Ocean. From the South China Sea (SCS) to the Arctic Ocean (AO), the range of Cant storage gradually increased with latitude. The maximum and minimum rates of ~0.6 mol C·m-2·yr-1, and ~0.2 mol C·m-2·yr-1 were seen in the AO and SCS, respectively. In the short term, warming and decline of ice cover may promote the transfer of excess CO2 from the atmosphere to the water interior; but on a longer time scale, a positive feedback (i.e., reduced CO2 absorption) may occur due to warming. Accordingly, the AO will likely no longer be a CO2 sink in the future when the sea ice disappears completely.
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