Isotope Studies of Methane Sources in Large Marine Anoxic Basins

本研究通过考虑海洋源端成员的同位素组成，更好地约束甲烷（CH 4）的全球地球化学循环。海洋甲烷包合物地球化学的几个方面最近重新引起的兴趣提出了一些有趣的问题，拟议的同位素信息可能会告知。 甲烷以海底天然气水合物的形式存在，可能是地球上已知最大的碳氢化合物储层。充分了解海洋中的甲烷循环至少有两个原因，一是评估其作为能源的潜力，二是评估海洋过去和未来的释气影响大规模气候变化的倾向。甲烷是一种强大的温室气体，其辐射影响约为。是二氧化碳的25倍。该项目的调查人员将测量水柱中甲烷的天然同位素组成（d 13 C-CH 4和d 2 H-CH 4，以及D 14 C-CH 4的一些测量值）以及沉积物中可疑的端元源，以构建组成混合模型。这项工作利用了黑海等缺氧盆地的有限循环，利用上覆水柱来综合CH 4通过水柱时不同来源和过程对CH 4的影响。这项研究将建立和扩展的d 13 C-CH 4和d 2 H-CH 4的初步测量从1988年黑海探险收集的样本。

ABSTRACTOCE-0099280This study sets out to better constrain the global biogeochemical cycle of methane, CH4, by a consideration of the isotopic composition of oceanic source end members. Recent renewed interest in several aspects of the geochemistry of marine methane clathrates poses a number of intriguing problems that the proposed isotopic information is likely to inform. Methane, in the form of submarine gas hydrates, potentially represents the largest known reservoir of hydrocarbons on the planet. It is important to fully understand the methane cycle in the oceans for at least two reasons, i) evaluation of its potential as an energy source, and ii) evaluation of the propensity of its past and future outgassings from the ocean to effect large scale climatic change. Methane is a powerful greenhouse gas, with a radiative impact approx. 25 times that of CO2. The investigators on this project will measure the natural isotopic composition of methane (d 13C-CH4 and d 2H-CH4 in addition to some measurements of D 14C-CH4) from the water column as well as suspected end-member sources in sediments in order to construct composition mixing models. The work takes advantage of the restricted circulation of anoxic basins such as the Black Sea, using the overlying water column to integrate the effects of different sources of and processes taking place on CH4 as it passes through the water column. The study will build on and extend preliminary measurements on d 13C-CH4 and d 2H-CH4 made on samples collected from a 1988 Black Sea expedition.