Estimation of methane fluxes from bottom sediments of Lake Baikal
Estimation of methane fluxes from bottom sediments of Lake Baikal
复制标题
贝加尔湖底部沉积物甲烷通量的估算
DOI：
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复制
发表时间：
2012
影响因子：
2.1
通讯作者：
I. B. Mizandrontsev
中科院分区：
文献类型：
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作者：
N. Granin;S. I. Muyakshin;M. Makarov;K. Kucher;I. Aslamov;L. Granina;I. B. Mizandrontsev
首次利用水声方法对贝加尔湖底部沉积物中气体火炬中的甲烷气泡通量进行了估算。早期的工作已经证明，在地震剖面中识别出底部模拟反射体的区域内外都存在天然气渗漏。通量从每年14吨到216吨不等，中部和南部盆地整个地区的通量从每年1 400吨到2 800吨不等。与其他水体的比较表明，贝加尔湖最强耀斑的通量与挪威海和鄂霍次克海相似。由于沉积作用，天然气水合物在水合物稳定带的下界分解。根据沉积产生的甲烷量计算，该湖泊中部和南部盆地每年的甲烷总量在2600至14000吨之间。根据粗略估计，浅水和深水天然气渗漏的总通量与沉积产生的甲烷量相似。这表明天然气水合物可能占据了接近天然气水合物稳定带底部的孔隙体积的10%以上，或者还有其他原因导致了这些底部沉积物的天然气水合物解离和气泡通量。
Methane bubble fluxes in gas flares from bottom sediments in Lake Baikal were estimated for the first time using hydroacoustic methods. Earlier work has demonstrated the occurrence of gas seeps both inside and outside of areas where bottom simulating reflectors were identified in seismic profiles. Fluxes ranged from 14 to 216 tons per year, with the flux for the entire area of the central and southern basins ranging from 1,400 to 2,800 tons per year. Comparison with other water bodies showed that fluxes from the most intensive Baikal flares were similar to those in the Norwegian and Okhotsk seas. Gas hydrates decompose at the lower boundary of the gas hydrate stability zone due to sedimentation. Calculation of the amount of methane produced due to sedimentation gave a total of between 2,600 and 14,000 tons per year for the central and southern basins of the lake. Based on rough estimation, the total flux from shallow- and deep-water gas seeps is similar to the amount of methane produced due to sedimentation. This suggests that gas hydrates possibly occupy much more than 10 % of the pore volume near the base of the gas hydrate stability zone, or that there are other reasons for gas hydrate dissociation and bubble flux from these bottom sediments.