Department of Ocean Science, The Hong Kong University of Science and Technology, Hong Kong, China.
Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China.
mSystems. 2024 Nov 19;9(11):e0031724. doi: 10.1128/msystems.00317-24. Epub 2024 Oct 15.
Marine biofilms were newly revealed as a giant microbial diversity pool for global oceans. However, the cyanobacterial diversity in marine biofilms within the upper seawater column and its ecological and evolutionary implications remains undetermined. Here, we reconstructed a full picture of modern marine cyanobacteria habitats by re-analyzing 9.3 terabyte metagenomic data sets and 2,648 metagenome-assembled genomes (MAGs). The abundances of cyanobacteria lineages exclusively detected in marine biofilms were up to ninefold higher than those in seawater at similar sample size. Analyses revealed that cyanobacteria in marine biofilms are specialists with strong geographical and environmental constraints on their genome and functional adaption, which is in stark contrast to the generalistic features of seawater-derived cyanobacteria. Molecular dating suggests that the important diversifications in biofilm-forming cyanobacteria appear to coincide with the Great Oxidation Event (GOE), "boring billion" middle Proterozoic, and the Neoproterozoic Oxidation Event (NOE). These new insights suggest that marine biofilms are large and important cyanobacterial factories for the global oceans.
Cyanobacteria, highly diverse microbial organisms, play a crucial role in Earth's oxygenation and biogeochemical cycling. However, their connection to these processes remains unclear, partly due to incomplete surveys of oceanic niches. Our study uncovered significant cyanobacterial diversity in marine biofilms, showing distinct niche differentiation compared to seawater counterparts. These patterns reflect three key stages of marine cyanobacterial diversification, coinciding with major geological events in the Earth's history.
海洋生物膜最近被揭示为全球海洋中巨大的微生物多样性库。然而，海洋生物膜中的蓝细菌多样性及其生态和进化意义仍未确定。在这里，我们通过重新分析 9.3 太字节的宏基因组数据集和 2648 个宏基因组组装基因组（MAG），重建了现代海洋蓝细菌栖息地的全貌。在类似样本大小的情况下，仅在海洋生物膜中检测到的蓝细菌谱系的丰度高达海水的九倍。分析表明，海洋生物膜中的蓝细菌是专家，其基因组和功能适应具有强烈的地理和环境限制，这与海水来源的蓝细菌的一般性特征形成鲜明对比。分子定年表明，生物膜形成蓝细菌的重要多样化似乎与大氧化事件（GOE）、中元古代的“无聊十亿年”和新元古代氧化事件（NOE）同时发生。这些新的见解表明，海洋生物膜是全球海洋中大型且重要的蓝细菌工厂。
蓝细菌是高度多样化的微生物，在地球的氧化和生物地球化学循环中起着至关重要的作用。然而，它们与这些过程的联系仍不清楚，部分原因是对海洋生境的调查不完全。我们的研究揭示了海洋生物膜中存在显著的蓝细菌多样性，与海水相比表现出明显的生态位分化。这些模式反映了海洋蓝细菌多样化的三个关键阶段，与地球历史上的主要地质事件同时发生。
