Deep subsurface microbial communities are more abundant in coarse-grained sedimentary rocks such as sandstones than in fine-grained mudstones. The low porosity and low permeability of mudstones are believed to restrict microbial life. Then, it is expected that distinct, isolated microbial communities may form in sandstones separated by mudstones. In this context, the connectivity between microbial communities in different sandstone units can be investigated to infer evolutionary patterns of diversification in space-time, which may potentially contribute with relevant data for analyses of hydraulic connectivity and stratigraphic correlation. In this work, we used high throughput DNA sequencing of a ribosomal 16S gene fragment to characterize the prokaryotic communities found in Permian sandstone samples of the same core that are separated by one mudstone interval, in the Charqueadas coal field, Parana Basin (Southern Brazil). Our samples were collected at ∼300 m deep, in porous sandstones separated by a thick mudstone package. Differences in the bacterial community structure between samples were observed for the classified OTUs, from phylum to genus. Molecular biology might be further applied as a possible tool to help to understand the spatial and temporal distribution of depositional facies, and the efficiency of low permeability rocks to compartmentalize reservoirs. Ongoing studies aim to extend the present investigation into further analyses regarding lateral changes in microbial communities present in the same sandstone units.

中文翻译：

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在两个由泥岩层隔开的砂岩单元中不同的深层地下微生物群落

深层地下微生物群落在诸如砂岩的粗颗粒沉积岩中比在细颗粒泥岩中更为丰富。泥岩的低孔隙度和低渗透性被认为限制了微生物的寿命。然后，预计在由泥岩分隔的砂岩中可能会形成独特的，孤立的微生物群落。在这种情况下，可以研究不同砂岩单元中微生物群落之间的连通性，以推断出时空多样化的演化模式，这可能有助于分析水力连通性和地层相关性的相关数据。在这项工作中 我们使用核糖体16S基因片段的高通量DNA测序来表征在巴拉那盆地（巴西南部）的Charqueadas煤田中，在同一岩心的二叠纪砂岩样品中发现的原核群落，这些岩心被一个泥岩层段隔开。我们的样品收集在约300 m深的多孔砂岩中，该砂岩被厚厚的泥岩包裹隔开。对于从门到属的分类OTU，观察到了样品之间细菌群落结构的差异。分子生物学可能会被进一步用作可能的工具，以帮助了解沉积相的时空分布以及低渗透率岩石将储层划分的效率。