Origin of Deep Methane from Active Faults along the Itoigawa Shizuoka Tectonic Line between the Eurasian and North American Plates: 13C/12C and 14C/12C Methane Profiles from a Pull-Apart Basin at Lake Suwa
Origin of Deep Methane from Active Faults along the Itoigawa Shizuoka Tectonic Line between the Eurasian and North American Plates: 13C/12C and 14C/12C Methane Profiles from a Pull-Apart Basin at Lake Suwa
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欧亚板块和北美板块之间糸鱼川静冈构造线沿线活动断层的深层甲烷来源：诹访湖拉分盆地的 13C/12C 和 14C/12C 甲烷剖面
DOI：
10.1021/acsearthspacechem.1c00392
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发表时间：
2022
影响因子：
3.4
通讯作者：
Park Ho-Dong
中科院分区：
文献类型：
--
作者：
Urai Atsushi;Takano Yoshinori;Matsui Yohei;Iwata Hiroki;Miyairi Yosuke;Yokoyama Yusuke;Miyabara Yuichi;Ohkouchi Naohiko;Park Ho-Dong
稳定和放射性碳同位素分析为水圈生态系统中的碳动态提供了有价值的见解。含有深层甲烷（CH 4）渗出的湖泊可能为阐明这种动态提供理想的环境，包括深层碳在地表生态系统及其食物网中的参与。在这项研究中，我们进行了碳同位素分析渗漏气体，湖水，蓝藻水华样本收集在湖Suwa，一个拉分盆地的Itoigawa-Shizuoka构造线，日本。在距离湖岸100 m处的两个渗漏点采集的CH 4均为14 C亏损（Δ 14 C =-972.1 ~989.8 ‰），表明渗漏CH 4和湖岸附近采集的底栖气泡CH 4（Δ 14 C = +21.7‰）的来源不同。结果表明，底栖气泡CH 4是由底栖沉积物中的产甲烷古菌产生的，渗漏CH 4是由产甲烷古菌利用残炭产生的。在渗漏点和湖岸附近采集的表层湖水溶解无机碳（DIC）的Δ 14 C值（Δ 14 C = −103.1 ‰ ~ −630.6 ‰）表明，深层碳的影响不仅发生在渗漏点附近，也发生在湖岸附近。蓝藻水华样本的Δ 14 C值也显示出与DIC相似的值（Δ 14 C = −110.3‰），表明地表水中10-63%的DIC和初级生产者中10%的DIC来自残余碳，包括CH 4和CO2，并被纳入了Suwa湖的地表生态系统。
Stable and radiocarbon isotope analyses provide valuable insights into carbon dynamics in hydrosphere ecosystems. A lake containing seeps of deep methane (CH4) may provide an ideal environment for elucidating such dynamics, including the involvement of deep carbon in the surface ecosystem and its food web. In this study, we performed carbon isotope analysis of seep gas, lake water, and a cyanobacterial bloom sample collected at Lake Suwa, a pull-apart basin on the Itoigawa–Shizuoka tectonic line, Japan. CH4collected from two seep sites 100 m from the lakeshore was14C-depleted (Δ14C = −972.1 to −989.8‰), indicating that the origins of seep CH4and benthic bubble CH4(Δ14C = +21.7‰) collected near the lakeshore differed. The results suggested that benthic bubble CH4was produced by methanogenic archaea in benthic sediments and that seep CH4was produced by methanogenic archaea using relic carbon. The Δ14C values of dissolved inorganic carbon (DIC) in surface lake water collected at seep sites (Δ14C = −103.1 to −630.6‰) and near the lakeshore (Δ14C = −100.9‰) suggested that the influence of deep carbon occurred not only around the seep sites but also at the lakeshore. The Δ14C values of the cyanobacterial bloom sample also showed values similar to those of DIC (Δ14C = −110.3‰), suggesting that 10–63% of DIC in surface water and 10% in primary producers originated from relic carbon, including CH4and CO2, and was incorporated into the surface ecosystem of Lake Suwa.