Microbial diversity in a vertical gradient Raw sequence reads

High elevation ecosystems in high Andes are considered one of the most extreme environments on Earth, characterized by the presence of periglacial soils that may be analogous to the polar regions of Mars. Llullaillaco volcano (6739 masl) is located on the Chilean-Argentinian border. We studied the distribution of microorganisms in an altitude gradient, considering their polyextreme conditions. 21 soil samples were taken from 5100 masl to 6200 masl each 200 m (3 replicates per altitude) to analyze the microbial communities using the bacterial 16S rRNA gene (Illumina). Our analyses performed by MOTHUR showed a total of 652108 sequences and 24232 different OTUs. Moreover, we detected a total of 26 different phyla. We observed that the microbial structure based in nMDS analyses from 5100 to 5600 masl samples are similar in composition and abundance dominated mainly by Actinobacteria and Proteobacteria. Nevertheless, samples from 5800 to 6200 mals present specific niches dominated by Proteobacteria (6200 masl sample).

安第斯高海拔生态系统被认为是地球上最极端的环境之一，其核心特征为存在与火星极地环境相似的冰缘土壤（periglacial soils）。坐落于智利与阿根廷边境的尤耶亚科火山（Llullaillaco volcano）海拔达6739米（meters above sea level，masl）。本研究针对该区域微生物在海拔梯度上的分布规律展开探究，同时考量其所处的多重极端环境条件。我们共采集21份土壤样本，采样覆盖海拔5100米至6200米的区间，每200米设置一个采样点，每个海拔设置3个生物学重复，采用基于细菌16S核糖体RNA基因（16S rRNA gene）的Illumina测序技术对微生物群落进行分析。经MOTHUR软件完成的分析共得到652108条序列与24232个不同的操作分类单元（Operational Taxonomic Units，OTU），此外共检测到26个不同的细菌门类。基于非度量多维尺度分析（non-metric Multidimensional Scaling，nMDS）的结果显示，海拔5100米至5600米区间的样本其微生物群落结构在组成与丰度上均较为相似，主要以放线菌门（Actinobacteria）和变形菌门（Proteobacteria）为优势类群；然而，海拔5800米至6200米的样本则呈现出独特的生态位特征，其中6200米海拔的样本以变形菌门（Proteobacteria）为绝对优势类群。