ABSTRACT

Ice-free areas of Victoria Land, in Antarctica, are characterized by different terrestrial ecosystems, that are dominated by microorganisms supporting highly adapted communities. Despite the unique conditions of these ecosystems, reports on their bacterial diversity are still fragmentary. From this perspective, 60 samples from 14 localities were analyzed. These localities were distributed in coastal sites with differently developed biological soil crusts, inner sites in the McMurdo Dry Valleys with soils lacking of plant coverage, and a site called Icarus Camp, with a crust developed on a thin locally weathered substrate of the underlying parent granitic-rock. Bacterial diversity was studied through 16S rRNA metabarcoding sequencing. Communities diversity, composition and the abundance and composition of different taxonomic groups were correlated to soil physicochemical characteristics. Firmicutes, Bacteroidetes, Cyanobacteria and Proteobacteria dominated these communities. Most phyla were mainly driven by soil granulometry, an often disregarded parameter and other abiotic parameters. Bacterial composition differed greatly among the three macrohabitats, each having a distinct bacterial profile. Communities within the two main habitats (coastal and inner ones) were well differentiated from each other as well, therefore depending on site-specific physicochemical characteristics. A core community of the whole samples was observed, mainly represented by Firmicutes and Bacteroidetes.

中文翻译：

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维多利亚土地宏观区域（南极洲）高度分化的土壤细菌群落

摘要

南极洲维多利亚地的无冰区具有不同的陆地生态系统，这些生态系统以支持高度适应群落的微生物为主。尽管这些生态系统具有独特的条件，但关于其细菌多样性的报告仍然不完整。从这个角度分析了来自 14 个地点的 60 个样本。这些地点分布在具有不同发育的生物土壤结皮的沿海地点、土壤缺乏植物覆盖的麦克默多干谷的内部地点，以及一个称为伊卡洛斯营地的地点，其地壳发育在下伏母体花岗岩的局部风化薄基质上-岩石。通过 16S rRNA 元条形码测序研究细菌多样性。社区多样性，不同分类群的丰度和组成与土壤理化特征相关。厚壁菌门、拟杆菌门、蓝藻门和变形菌门占主导地位。大多数门主要由土壤粒度测量驱动，这是一个经常被忽视的参数和其他非生物参数。三种大型栖息地的细菌组成差异很大，每种都具有不同的细菌特征。两个主要栖息地（沿海和内部栖息地）内的群落彼此也有很好的区分，因此取决于特定地点的物理化学特征。观察到整个样品的核心群落，主要以厚壁菌门和拟杆菌门为代表。蓝藻和变形菌在这些群落中占主导地位。大多数门主要由土壤粒度测量驱动，这是一个经常被忽视的参数和其他非生物参数。三种大型栖息地的细菌组成差异很大，每种都具有不同的细菌特征。两个主要栖息地（沿海和内部栖息地）内的群落彼此也有很好的区分，因此取决于特定地点的物理化学特征。观察到整个样品的核心群落，主要以厚壁菌门和拟杆菌门为代表。蓝藻和变形菌在这些群落中占主导地位。大多数门主要由土壤粒度测量驱动，这是一个经常被忽视的参数和其他非生物参数。三种大型栖息地的细菌组成差异很大，每种都具有不同的细菌特征。两个主要栖息地（沿海和内部栖息地）内的群落彼此也有很好的区分，因此取决于特定地点的物理化学特征。观察到整个样品的核心群落，主要以厚壁菌门和拟杆菌门为代表。两个主要栖息地（沿海和内部栖息地）内的群落彼此也有很好的区分，因此取决于特定地点的物理化学特征。观察到整个样品的核心群落，主要以厚壁菌门和拟杆菌门为代表。两个主要栖息地（沿海和内部栖息地）内的群落彼此也有很好的区分，因此取决于特定地点的物理化学特征。观察到整个样品的核心群落，主要以厚壁菌门和拟杆菌门为代表。