Integrative Freshwater Ecology Group, Center for Advanced Studies of Blanes-CSIC. Acc. Cala St Francesc 14, E-17300, Blanes, Catalonia, Spain.
CREAF - CSIC, Campus UAB, Edifici C, 08193, Cerdanyola del Vallès, Catalonia, Spain.
Sci Rep. 2018 Mar 13;8(1):4457. doi: 10.1038/s41598-018-22835-3.
A rich eukaryotic planktonic community exists in high-mountain lakes despite the diluted, oligotrophic and cold, harsh prevailing conditions. Attempts of an overarching appraisal have been traditionally hampered by observational limitations of small, colorless, and soft eukaryotes. We aimed to uncover the regional eukaryotic biodiversity of a mountain lakes district to obtain general conclusions on diversity patterns, dominance, geographic diversification, and food-web players common to oligotrophic worldwide distributed freshwater systems. An unprecedented survey of 227 high-altitude lakes comprising large environmental gradients was carried out using Illumina massive tag sequencing of the 18S rRNA gene. We observed a large Chrysophyceae dominance in richness, abundance and novelty, and unveiled an unexpected richness in heterotrophic phagotrophs and parasites. In particular, Cercozoa and Chytridiomycota showed diversity features similar to the dominant autotrophic groups. The prominent beta-dispersion shown by parasites suggests highly specific interactions and a relevant role in food webs. Interestingly, the freshwater Pyrenean metacommunity contained more diverse specific populations than its closest marine oligotrophic equivalent, with consistently higher beta-diversity. The relevance of unseen groups opens new perspectives for the better understanding of planktonic food webs. Mountain lakes, with remarkable environmental idiosyncrasies, may be suitable environments for the genetic diversification of microscopic eukaryotic life forms.
尽管高海拔山区湖泊的条件通常为稀释、贫营养和寒冷、恶劣，但仍存在丰富的真核浮游生物群落。由于传统上受到小型、无色和柔软真核生物观测限制的阻碍，对其进行全面评估的尝试一直受到阻碍。我们旨在揭示山区湖泊区的区域真核生物多样性，以获得关于多样性模式、优势度、地理多样化以及与贫营养分布广泛的全球淡水系统共有的食物网参与者的一般结论。我们利用 Illumina 大规模标签测序 18S rRNA 基因，对包含大环境梯度的 227 个高海拔湖泊进行了前所未有的调查。我们观察到丰富度、丰度和新颖性方面的 Chyrsophyceae 优势明显，并揭示了出乎意料的异养吞噬者和寄生虫丰富度。特别是 Cercozoa 和 Chytridiomycota 表现出与优势自养群相似的多样性特征。寄生虫显著的β分散表明存在高度特定的相互作用和在食物网中发挥重要作用。有趣的是，淡水比利牛斯山后生动物群落包含比其最接近的海洋贫营养对应物更多样化的特定种群，其β多样性始终更高。看不见的群体的相关性为更好地理解浮游食物网开辟了新的视角。具有显著环境特质的山区湖泊可能是微观真核生物形式遗传多样化的合适环境。
