The Biogeochemical Cycle of Methane on the Northwestern Shelf of the Black Sea

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• 作者：I. I. Rusanov ; A. Yu. Lein ; N. V. Pimenov ; S. K. Yusupov and M. V. Ivanov
• 关键词：methane cycle ; Black Sea ; methanogenesis ; bacterial oxidation of methane ; daily methane production ; seasonal dynamics ; 13C of methane ; methane flux to the atmosphere
• 刊名：Microbiology
• 出版时间：2002
• 出版年：2002
• 期刊代码：42_00262617
• 类别：law
• 卷：71
• 期：4
• 页码：479-487
• 数据来源：sp

摘要

Seasonal investigations of methane distribution and rates of its oxidation and generation in the water column and sediments of the Black Sea northwestern shelf were carried out within the framework of the interdisciplinary projects European River–Ocean Systems (EROS-2000, EROS-21) and Biogenic Gases Exchange in the Black Sea (BigBlack) in August 1995, May 1997, and December 1999. Experiments that involved the addition of 14CH₃COONa and 14CO₂ to sediment samples showed the main part of methane to be formed from CO₂. Maximum values of methane production (up to 559 mol/(m2 day)) were found in coastal sediments in summer time. In winter and spring, methane production in the same sediments did not exceed 3.6–4.2 mol/(m2 day). The 13C values of methane ranged from –70.7 to –81.8, demonstrating its microbial origin and contradicting the concept of the migration of methane from cold seeps or from the oil fields located on the Black Sea shelf. Experiments that involved the addition of 14CH₄ to water and sediment samples showed that a considerable part of methane is oxidized in the upper horizons of bottom sediments and in the water column. Nevertheless, it was found that, in summer, part of the methane (from 6.8 to 320 mol/(m2 day)) arrives in the atmosphere.