Microbiological, molecular ecological, biogeochemical, and isotope geochemical research was carried out in four lakes of the central part of the Yamal Peninsula in the area of continuous permafrost. Two of them were large (73.6 and 118.6 ha) and deep (up to 10.6 and 12.3 m) mature lakes embedded into all geomorphological levels of the peninsula, and two others were smaller (3.2 and 4.2 ha) shallow (2.3 and 1.8 m) lakes which were formed as a result of thermokarst on constitutional (segregated) ground ice. Samples were collected in August 2019. The Yamal tundra lakes were found to exhibit high phytoplankton production (340–1200 mg C m⁻² d⁻¹) during the short summer season. Allochthonous and autochthonous, particulate and dissolved organic matter was deposited onto the bottom sediments, where methane was the main product of anaerobic degradation, and its content was 33–990 µmol CH₄ dm⁻³. The rates of hydrogenotrophic methanogenesis appeared to be higher in the sediments of deep lakes than in those of the shallow ones. In the sediments of all lakes, Methanoregula and Methanosaeta were predominant components of the archaeal methanogenic community. Methane oxidation (1.4–9.9 µmol dm⁻³ d⁻¹) occurred in the upper sediment layers simultaneously with methanogenesis. Methylobacter tundripaludum (family Methylococcaceae) predominated in the methanotrophic community of the sediments and the water column. The activity of methanotrophic bacteria in deep mature lakes resulted in a decrease in the dissolved methane concentration in lake water from 0.8–4.1 to 0.4 µmol CH₄ L⁻¹ d⁻¹, while in shallow thermokarst lakes the geochemical effect of methanotrophs was much less pronounced. Thus, only small, shallow Yamal lakes may contribute significantly to the overall diffusive methane emissions from the water surface during the warm summer season. The water column of large, deep lakes on Yamal acts, however, as a microbial filter preventing methane emission into the atmosphere. It can be assumed that climate warming will lead to an increase in the total area of thermokarst lakes, which will enhance the effect of methane release into the atmosphere.

中文翻译：

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亚马尔·苔原湖的水柱作为防止甲烷排放的微生物过滤器

在连续多年冻土区的亚马尔半岛中部的四个湖泊中进行了微生物学，分子生态学，生物地球化学和同位素地球化学研究。其中两个是大型的（73.6和118.6公顷）和深的（分别达到10.6和12.3 m）成熟的湖泊，被嵌入到半岛的所有地貌水平，另外两个较小的（面积分别为3.2和4.2公顷）浅层（2.3和1.8 m）天然喀斯特冰（隔离的）上因热喀斯特形成的湖泊。2019年8月收集了样本。发现亚马尔苔原湖的浮游植物产量很高（340–1200 mg C m ^-2  d ^-1）。异质和土质，颗粒状和溶解的有机物沉积在底部沉积物中，甲烷是厌氧降解的主要产物，其含量为33–990  µ mol CH ₄  dm ^-3。在深水湖泊的沉积物中，氢营养型甲烷生成的速率似乎比在浅水湖泊中的更高。在所有湖泊的沉积物中 ，甲烷菌属和甲烷菌属是古细菌产甲烷菌群落的主要成分。甲烷氧化（1.4–9.9  µ mol dm ^-3  d ^-1）在甲烷生成的同时在上层沉积层中发生。在沉积物和水柱的甲烷营养型群落中，以通栖的甲基杆菌（甲基球菌科）为主。深度成熟湖泊中甲烷营养细菌的活动导致湖水中溶解的甲烷浓度从0.8–4.1降低至0.4  µ mol CH ₄  L ^-1  d ^-1，而在浅热喀斯特湖中，甲烷氧化生物的地球化学作用就不那么明显了。因此，在温暖的夏季，只有很小的浅亚马尔湖可能对水面甲烷的总体扩散贡献很大。然而，亚马尔（Yamal）上大而深的湖泊的水柱起着微生物过滤器的作用，可防止甲烷排放到大气中。可以假定，气候变暖将导致热喀斯特湖的总面积增加，这将增强甲烷向大气中的释放作用。