The occurrence and magnitude of natural fossil methane (CH₄) emissions in the Arctic are poorly known. Emission of geologic CH₄, a potent greenhouse gas, originating beneath permafrost is of particular interest due to the potential for positive feedback to climate warming, whereby accelerated permafrost thaw releases permafrost-trapped CH₄ in a future warmer climate. The development of through-going taliks in Arctic lakes overlying hydrocarbon reservoirs is one mechanism of releasing geologically sourced, subpermafrost CH₄. Here we use novel gas flux measurements, geophysical observations of the subsurface, shallow sediment coring, high-resolution bathymetry measurements, and lake water chemistry measurements to produce a synoptic survey of the gas vent system in Esieh Lake, a northwest Alaska lake with exceedingly large geologic CH₄ seep emissions. We find that microbially produced fossil CH₄ is being vented though a narrow thaw conduit below Esieh Lake through pockmarks on the lake bottom. This is one of the highest flux geologic CH₄ seep fields known in the terrestrial environment and potentially the highest flux single methane seep. The poleward retreat of continuous permafrost may have implications for more subcap CH₄ release with increased permafrost thaw.

中文翻译：

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永久冻土融化对极端地质甲烷渗漏的影响

北极地区天然化石甲烷 (CH ₄ ) 排放的发生和量级鲜为人知。源自永久冻土层下的地质 CH _{4 的}排放特别令人感兴趣，因为它可能对气候变暖产生正反馈，从而加速永久冻土融化会在未来温暖的气候中释放被永久冻土困住的 CH ₄。在上覆油气藏的北极湖泊中开发贯穿式 taliks 是释放地质来源的冻土下 CH _{4 的}机制之一. 在这里，我们使用新颖的气体通量测量、地下地球物理观测、浅层沉积物取心、高分辨率测深测量和湖水化学测量，对阿拉斯加西北部湖泊 Esieh 湖的排气系统进行了天气调查。地质 CH ₄渗漏排放。我们发现微生物产生的化石 CH ₄正在通过 Esieh 湖下方的狭窄解冻管道通过湖底的麻坑排出。这是陆地环境中已知的最高通量地质 CH ₄渗流场之一，并且可能是最高通量的单一甲烷渗流。连续多年冻土的极地退缩可能对更多的子上限 CH ₄产生影响 随着永久冻土融化的增加而释放。