The freshwater ultraoligotrophic Lake Labynkyr is located near the Pole of Cold in the northern hemisphere (Yakutia, Russia). The lake is covered by ice during 240 days a year. We undertook several expeditions to the lake during the ice and open water periods for sampling ice fouling, plankton and periphyton that were then analyzed by means of scanning electron microscopy. As a result, we identified a high biodiversity of diatoms—123 species and intraspecific taxa from 53 genera, among them 3 species were new for Russia and 26 taxa were new for the algal flora of Yakutia. The oligo- and xenosaprobionts and their variations dominate—71 taxa. 18 Species were evaluated as tolerant to cold oligotrophic waters, 12 occurred on the ice bottom, and 62 in the water column under ice (0–25 m). 104 taxa were found during the open water period, 70 taxa were identified in the periphyton. We showed the diatom flora of Lake Labynkyr to be unique compared with other lakes of Yakutia and to share taxa with the diatom flora of Lake Baikal. The diatoms being indicators of the global climate changes and ecological status of lakes, our data can be used as an evidence of such changes as well as to be useful studies of biogeography and history of formation of flora in Arctic and Subarctic waters.

中文翻译：

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深入了解北半球冷极极冷的超贫营养拉宾克尔湖的硅藻多样性、生态和生物地理学。


淡水超贫营养湖 Labynkyr 位于北半球冷极附近（俄罗斯雅库特）。一年中有240天该湖被冰覆盖。我们在结冰和开放水域期间对湖泊进行了几次考察，对冰垢、浮游生物和附生生物进行了采样，然后通过扫描电子显微镜进行了分析。结果，我们确定了硅藻的高度生物多样性——123个物种和53个属的种内分类单元，其中3个物种是俄罗斯新物种，26个分类单元是雅库特藻类植物新物种。寡菌和异菌微生物及其变异占主导地位——71 个分类单元。 18 个物种被评估为对寒冷寡营养水域具有耐受性，其中 12 个物种出现在冰底，62 个物种出现在冰下水柱（0-25 m）中。在开放水域期间发现了104个类群，在附生生物中发现了70个类群。我们表明，拉宾克尔湖的硅藻植物群与雅库特其他湖泊相比是独一无二的，并且与贝加尔湖的硅藻植物群共享类群。硅藻是全球气候变化和湖泊生态状况的指标，我们的数据可以用作此类变化的证据，也可以用于北极和亚北极水域生物地理学和植物群形成历史的有用研究。