近日，美国加州大学圣巴巴拉分校Leigh Anne Riedman团队提出早期的真核生物化石很可能是底栖需氧生物。相关论文发表在2026年5月20日出版的《自然》杂志上。

真核细胞的演化为地球上所有复杂生命的出现铺平了道路。尽管意义重大，但早期真核生物演化的环境背景却很大程度上仍未知。

研究组利用地质记录重建了已知最古老的真核生物化石（约14-17.5亿年前）的栖息地。综合古生物学、沉积学和地球化学分析表明，尽管这些真核生物化石出现在从近岸到远岸的多种沉积环境中，但它们几乎完全局限于底层水体含氧的区域。这一分布特征表明这些生物是好氧生物（专性、兼性和/或微好氧），并且考虑到其大小和形态复杂性，很可能已拥有线粒体。

此外，它们在其他富含化石的缺氧样品中几乎不存在，这表明它们是底栖生活的，因为浮游真核生物本应同时出现在含氧和缺氧样品中。研究组提出，在元古宙的大部分时期，真核生物大多局限于含氧的底栖生境，直到新元古代（5.4-10亿年前）才扩展到浮游生境。这种晚期的生态扩展可以解释真核生物实体化石与分子生物标志物出现时间的不匹配，并说明新元古代真核生物多样性呈逐步增长的原因。

附：英文原文

Title: Early fossil eukaryotes were benthic aerobes

Author: Lechte, Maxwell A., Riedman, Leigh Anne, Porter, Susannah M., Halverson, Galen P., Whelan, Margaret

Issue&Volume: 2026-05-20

Abstract: The evolution of the eukaryotic cell paved the way for the emergence of all complex life on Earth. Despite its significance, the environmental context of early eukaryote evolution is largely unknown1,2. Here we use the geological record to reconstruct the habitats of the oldest known fossil eukaryotes, approximately 1.75–1.4 billion years old. Our integrated palaeontological, sedimentological and geochemical analyses show that although fossil eukaryotes are found in samples deposited in a range of environments from coastal to offshore, they are almost entirely restricted to those from settings with oxygenated bottom waters. This distribution suggests these organisms were aerobes (obligate, facultative and/or microaerophilic) and, given their size and morphological complexity, probably possessed mitochondria. Furthermore, their near absence from otherwise fossiliferous anoxic samples suggests a benthic habit, as planktonic eukaryotes would be expected to be present in both oxic and anoxic samples. We propose that eukaryotes were largely restricted to oxic benthic habitats for much of the Proterozoic eon, only expanding into planktonic habitats during the Neoproterozoic era (1–0.54 billion years ago). This late ecological expansion could account for the mismatch between the appearance of eukaryotic body fossils and molecular biomarkers3 and explain the stepwise increase in eukaryote diversity during the Neoproterozoic era4.

DOI: 10.1038/s41586-026-10533-4

Source: https://www.nature.com/articles/s41586-026-10533-4