Department of Mechanical Engineering, Kitami Institute of Technology, Koencho-165, Kitami 090-8507, Japan.
Graduate School of Engineering, Kobe University, 1-1 Rokkodai-Cho Nada-Ku, Kobe 658-8501, Japan.
Mar Pollut Bull. 2022 Jul;180:113792. doi: 10.1016/j.marpolbul.2022.113792. Epub 2022 Jun 2.
Strong stratification has formed in Lake Abashiri, a typical meromictic lake in Hokkaido, in the subarctic zone in Japan. When the anoxic water of the lower layer is upwelled to the surface by a strong wind, fish and corbicula clams die due to a lack of dissolved oxygen. This event is called as blue tide. It was observed that the dissolved methane in the lake decreased more than 100 t after the blue tide which occurred in 2008. This is the discovery of the phenomenon that a large quantity of methane diffuses to the atmosphere caused by upwelling of anoxic water which contains dissolved methane. We named the event as "methane burst". It is also the first report that the wind-driven upwelling is reproduced using a numerical analysis code and the methane burst is analyzed. During this blue tide, the methane flux was approximately 170 times greater than usual.
在日本亚寒带的北海道，有一个典型的分层型咸水湖——网走湖，这里已经形成了很强的分层现象。当强风将底层缺氧水带到表面时，鱼类和河蚬会因缺氧而死亡。这种现象被称为蓝潮。据观察，2008 年发生蓝潮后，湖中溶解的甲烷减少了 100 多吨。这是首次发现大量甲烷因含溶解甲烷的缺氧水上升而扩散到大气中的现象。我们将这一现象命名为“甲烷爆发”。这也是首次使用数值分析代码重现风生上升流并分析甲烷爆发的报告。在这次蓝潮中，甲烷通量大约是平时的 170 倍。
