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利用吹扫捕集法在“大洋一号”船上现场探测到Logatchev热液场水柱上方及附近存在明显的甲烷羽状流.测定结果显示,热液区海水甲烷背景含量为1.05～1.68nmol/L,明显高于大西洋深海平原正常海水甲烷背景值(0.4～0.5nmol/L),表明热液系统是海水溶解甲烷的重要来源之一;在垂直剖面上,甲烷含量最大异常值的变化范围为7.14～113.90nmol/L,其对应的水深为离海底180～500m.羽状流中甲烷浓度分布以及羽状流的结构特征可能受下方热液喷发供应、洋流混合和微生物氧化消耗等过程控制.另外,MAR-CTD3站甲烷的分布规律明显不同于其他站位,可能暗示周围存在新的热液喷口.探测到甲烷羽状流之处同时还伴随温度和浊度的异常,有力证明了甲烷羽状流的存在是找寻海底热液活动地点最有效的手段之一.
A clear methane plume flow was observed above and near the water column of Logatchev hydrothermal field on the “Dayang No.1” ship by means of purge and trap method.The results showed that the background content of methane in the hydrothermal zone was 1.05 ~ 1.68nmol / L , Which is obviously higher than the background value of normal seawater (0.4 ~ 0.5nmol / L) in the deep ocean of the Atlantic Ocean, indicating that the hydrothermal system is one of the important sources of methane dissolved in seawater. In the vertical section, the maximum anomaly range of methane content is 7.14 ~ 113.90nmol / L, corresponding to a water depth of 180-500m from the seafloor.The distribution of methane concentration in the plume and the structural characteristics of the plume may be controlled by processes such as hydrothermal fluid supply, ocean current mixing and microbial oxidation and so on. , The distribution of methane in MAR-CTD3 station is obviously different from other stations, suggesting that there may be new hydrothermal vents nearby.The detection of methane plume flow along with the anomaly of temperature and turbidity strongly proved that the methane plume The existence of the stream is one of the most effective means of finding the hydrothermal activity of the seafloor.