Despite evidence for microbial endemism, an understanding of the impact of geological and paleoclimate events on the evolution of regional protist communities remains elusive. Here, we provide insights into the biogeographical history of Antarctic freshwater diatoms, using lacustrine fossils from mid-Miocene and Quaternary Antarctica, and dovetail this dataset with a global inventory of modern freshwater diatom communities. We reveal the existence of a diverse mid-Miocene diatom flora bearing similarities with several former Gondwanan landmasses. Miocene cooling and Plio-Pleistocene glaciations triggered multiple extinction waves, resulting in the selective depauperation of this flora. Although extinction dominated, in situ speciation and new colonizations ultimately shaped the species-poor, yet highly adapted and largely endemic, modern Antarctic diatom flora. Our results provide a more holistic view on the scale of biodiversity turnover in Neogene and Pleistocene Antarctica than the fragmentary perspective offered by macrofossils and underscore the sensitivity of lacustrine microbiota to large-scale climate perturbations.

中文翻译：

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南极洲大尺度气候动力学导致南方硅藻灭绝

尽管有微生物特有的证据，但对地质和古气候事件对区域原生生物群落进化的影响的理解仍然难以捉摸。在这里，我们使用来自中新世中期和第四纪南极洲的湖泊化石，提供对南极淡水硅藻生物地理历史的见解，并将该数据集与现代淡水硅藻群落的全球清单相吻合。我们揭示了与几个前冈瓦纳大陆相似的中新世中期硅藻植物群的存在。中新世冷却和上更新世冰川作用引发了多次灭绝波，导致该植物群的选择性衰退。尽管灭绝占主导地位，但原地物种形成和新的殖民化最终塑造了物种贫乏但高度适应且在很大程度上是地方性的，现代南极硅藻植物群。我们的研究结果为新近纪和更新世南极洲的生物多样性周转规模提供了更全面的观点，而不是大化石提供的零碎观点，并强调了湖泊微生物群对大规模气候扰动的敏感性。