Yi Zhenzhen, Berney Cedric, Hartikainen Hanna, Mahamdallie Shazia, Gardner Michelle, Boenigk Jens, Cavalier-Smith Thomas, Bass David
Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, South China Normal University, Guangzhou 510631, China.
Department of Life Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK.
FEMS Microbiol Ecol. 2017 Aug 1;93(8). doi: 10.1093/femsec/fix073.
We performed high-throughput 18S rDNA V9 region sequencing analyses of microeukaryote (protist) communities at seven sites with depths ranging from 0 to 1450 m in the southern part of Lake Baikal. We show that microeukaryotic diversity differed according to water column depth and sediment depth. Chrysophytes and perkinsids were diverse in subsurface samples, novel radiations of petalomonads and Ichthyobodo relatives were found in benthic samples, and a broad range of divergent OTUs were detected in deep subbenthic samples. Members of clades usually associated with marine habitats were also detected, including syndineans for the first time in freshwater systems. Fungal- and cercozoan-specific c. 1200 bp amplicon clone libraries also revealed many novel lineages in both planktonic and sediment samples at all depths, a novel radiation of aphelids in shallower benthic samples, and partitioning of sarcomonad lineages in shallow vs deep benthic samples. Putative parasitic lineages accounted for 12.4% of overall reads, including a novel radiation of Ichthyobodo (fish parasite) relatives. Micrometazoans were also analysed, including crustaceans, rotifers and nematodes. The deepest (>1000 m) subsurface sediment samples harboured some highly divergent sequence types, including heterotrophic flagellates, parasites, putative metazoans and sequences likely representing organisms originating from higher up in the water column.
我们对贝加尔湖南部7个深度范围从0至1450米的位点的微型真核生物（原生生物）群落进行了高通量18S rDNA V9区域测序分析。我们发现微型真核生物的多样性随水柱深度和沉积物深度而有所不同。金藻和帕金虫在次表层样本中具有多样性，花瓣虫和艾氏藻亲属的新辐射类群在底栖样本中被发现，并且在深海底栖样本中检测到了广泛的不同OTU。通常与海洋栖息地相关的进化枝成员也被检测到，包括在淡水系统中首次发现的聚缩虫。真菌和丝足虫特异性的约1200 bp扩增子克隆文库在所有深度的浮游和沉积物样本中也揭示了许多新谱系，在较浅的底栖样本中有新辐射的无尾鞭毛虫，以及浅底栖和深底栖样本中肉足虫谱系的划分。假定的寄生谱系占总读数的12.4%，包括艾氏藻（鱼类寄生虫）亲属的新辐射类群。我们还分析了微型后生动物，包括甲壳类动物、轮虫和线虫。最深（>1000米）的次表层沉积物样本含有一些高度不同的序列类型，包括异养鞭毛虫、寄生虫、假定的后生动物以及可能代表来自水柱中较高位置生物的序列。
