Only a few palaeo-records extend beyond the Holocene in Yakutia, eastern Siberia, since most of the lakes in the region are of Holocene thermokarst origin. Thus, we have a poor understanding of the long-term interactions between terrestrial and aquatic ecosystems and their response to climate change. The Lake Khamra region in southwestern Yakutia is of particular interest because it is in the transition zones from discontinuous to sporadic permafrost and from summergreen to evergreen boreal forests. Our multiproxy study of Lake Khamra sediments reaching back to the Last Glacial Maximum 21 cal ka BP, includes analyses of organic carbon, nitrogen, XRF-derived elements, sedimentary ancient DNA amplicon sequencing of aquatic and terrestrial plants and diatoms, as well as classical counting of pollen and non-pollen palynomorphs (NPP). The palaeogenetic approach revealed 45 diatom, 191 terrestrial plant, and 65 aquatic macrophyte taxa. Pollen analyses identified 34 pollen taxa and 28 NPP taxa. The inferred terrestrial ecosystem of the Last Glacial comprises tundra vegetation dominated by forbs and grasses, likely inhabited by megaherbivores. By 18.4 cal ka BP a lake had developed with a high abundance of macrophytes and dominant fragilarioid diatoms, while shrubs expanded around the lake. In the Bølling-Allerød at 14.7 cal ka BP both the terrestrial and aquatic systems reflect climate amelioration, alongside lake water-level rise and woodland establishment, which was curbed by the Younger Dryas cooling. In the Early Holocene warmer and wetter climate led to taiga development and lake water-level rise, reflected by diatom composition turnover from only epiphytic to planktonic diatoms. In the Mid-Holocene the lake water level decreased at ca. 8.2 cal ka BP and increased again at ca. 6.5 cal ka BP. At the same time mixed evergreen-summergreen forest expanded. In the Late Holocene, at ca. 4 cal ka BP, vegetation cover similar to modern conditions established. This study reveals the long-term shifts in aquatic and terrestrial ecosystems and a comprehensive understanding of lake development and catchment history of the Lake Khamra region.

中文翻译：

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根据 sedaDNA、花粉和 XRF 数据推断西伯利亚雅库特西南部的晚冰期和全新世植被和湖泊变化

在西伯利亚东部的雅库特，只有少数古记录延伸到全新世之后，因为该地区的大多数湖泊都是全新世热岩溶起源的。因此，我们对陆地和水生生态系统之间的长期相互作用及其对气候变化的响应知之甚少。雅库特西南部的卡姆拉湖地区特别令人感兴趣，因为它位于从不连续的永久冻土到零星的永久冻土以及从夏绿到常绿的北方森林的过渡区域。我们对卡姆拉湖沉积物的多代理研究可追溯到末次盛冰期 21 cal ka BP，包括有机碳、氮、XRF 衍生元素的分析、水生和陆生植物和硅藻的沉积古 DNA 扩增子测序以及经典计数花粉和非花粉孢粉型（NPP）。古生成方法揭示了 45 种硅藻、191 种陆生植物和 65 种水生植物类群。花粉分析确定了 34 个花粉类群和 28 个 NPP 类群。推断的末次冰期陆地生态系统包括以杂草和禾本科植物为主的苔原植被，可能居住着大型食草动物。到 18.4 cal ka BP 时，一个湖泊已经发育，拥有大量的大型植物和占主导地位的脆弱硅藻，而灌木丛在湖周围扩张。在 Bølling-Allerød 14.7 cal ka BP 中，陆地和水生系统都反映了气候的改善，同时湖泊水位上升和林地建设也受到了新仙女木期降温的抑制。在全新世早期，温暖湿润的气候导致了针叶林的发育和湖泊水位的上升，这反映在硅藻成分从附生硅藻到浮游硅藻的转变上。在全新世中期，湖水位下降了大约。 8.2 cal ka BP 并在 ca 再次增加。 6.5 卡卡血压。与此同时，常绿-夏绿混交林不断扩大。在全新世晚期，大约。 4 cal ka BP，植被覆盖与现代条件相似。这项研究揭示了水生和陆地生态系统的长期变化，并全面了解卡姆拉湖地区的湖泊发展和流域历史。