Soufi Hengameh H, Porch Robert, Korchagina Masha V, Abrams Joseph A, Schnider Jared S, Carr Ben D, Williams Mark A, Louca Stilianos
Department of Biology, University of Oregon, Eugene, OR, USA.
Institute of Ecology and Evolution, University of Oregon, Eugene, OR, USA.
Commun Biol. 2024 Dec 19;7(1):1663. doi: 10.1038/s42003-024-07384-y.
The factors shaping microbial communities in marine subsurface sediments remain poorly understood. Here, we analyzed the microbiome of subsurface sediments within a depth range of 1.6-1.9 m, at 10 locations along the Oregon coast. We used metagenomics to reconstruct the functional structure and 16S rRNA gene amplicon sequencing to estimate the taxonomic composition of microbial communities, accompanied by physicochemical measurements. Functional community structure, in terms of the proportions of various gene groups, was remarkably stable across samples, despite the latter covering a region spanning over 300 km. In contrast, taxonomic composition was highly variable, especially at the level of amplicon sequence variants (ASVs) and operational taxonomic units (OTUs). Mantel correlation tests between compositional dissimilarities and geographic distances revealed only a moderate influence of distance on composition. Regression models predicting taxonomic dissimilarities and considering up to 20 physicochemical variables as predictors, almost always failed to select a significant predictor, suggesting that variation in local conditions does not explain the high taxonomic variability. Permutation null models of community assembly revealed that taxa tend to strongly segregate, i.e., exclude each other. We conclude that biological interactions are important drivers of taxonomic variation in subsurface sediments, and that this variation can decouple from functional structure.
塑造海洋地下沉积物中微生物群落的因素仍知之甚少。在此，我们分析了俄勒冈海岸沿线10个地点深度范围为1.6 - 1.9米的地下沉积物的微生物组。我们使用宏基因组学来重建功能结构，并通过16S rRNA基因扩增子测序来估计微生物群落的分类组成，同时进行了物理化学测量。尽管样本覆盖了超过300公里的区域，但就各种基因组的比例而言，功能群落结构在不同样本中非常稳定。相比之下，分类组成高度可变，尤其是在扩增子序列变体（ASV）和操作分类单元（OTU）水平上。组成差异与地理距离之间的Mantel相关性测试表明，距离对组成的影响仅为中等程度。预测分类差异并将多达20个物理化学变量作为预测因子的回归模型几乎总是未能选择出显著的预测因子，这表明局部条件的变化并不能解释高度的分类变异性。群落组装的置换零模型表明，分类群倾向于强烈分离，即相互排斥。我们得出结论，生物相互作用是地下沉积物中分类变异的重要驱动因素，并且这种变异可能与功能结构脱钩。
