Department of Ecology, Environment and Plant Sciences, Stockholm University, 106 91, Stockholm, Sweden.
Baltic Sea Centre, Stockholm University, Stockholm, Sweden.
Microbiome. 2022 Aug 15;10(1):126. doi: 10.1186/s40168-022-01321-z.
Microorganisms in the seafloor use a wide range of metabolic processes, which are coupled to the presence of functional genes within their genomes. Aquatic environments are heterogenous and often characterized by natural physiochemical gradients that structure these microbial communities potentially changing the diversity of functional genes and its associated metabolic processes. In this study, we investigated spatial variability and how environmental variables structure the diversity and composition of benthic functional genes and metabolic pathways across various fundamental environmental gradients. We analyzed metagenomic data from sediment samples, measured related abiotic data (e.g., salinity, oxygen and carbon content), covering 59 stations spanning 1,145 km across the Baltic Sea.
The composition of genes and microbial communities were mainly structured by salinity plus oxygen, and the carbon to nitrogen (C:N) ratio for specific metabolic pathways related to nutrient transport and carbon metabolism. Multivariate analyses indicated that the compositional change in functional genes was more prominent across environmental gradients compared to changes in microbial taxonomy even at genus level, and indicate functional diversity adaptation to local environments. Oxygen deficient areas (i.e., dead zones) were more different in gene composition when compared to oxic sediments.
This study highlights how benthic functional genes are structured over spatial distances and by environmental gradients and resource availability, and suggests that changes in, e.g., oxygenation, salinity, and carbon plus nitrogen content will influence functional metabolic pathways in benthic habitats. Video Abstract.
海底微生物利用广泛的代谢过程，这些过程与它们基因组中的功能基因的存在相关联。水生环境是异质的，通常具有天然的物理化学梯度，这些梯度可能改变功能基因的多样性及其相关的代谢过程，从而影响这些微生物群落的结构。在这项研究中，我们调查了空间变异性，以及环境变量如何跨各种基本环境梯度构建底栖功能基因和代谢途径的多样性和组成。我们分析了来自沉积物样本的宏基因组数据，测量了相关的非生物数据（例如盐度、氧气和碳含量），涵盖了波罗的海 1145 公里范围内的 59 个站点。
基因和微生物群落的组成主要由盐度加氧气以及与营养物质运输和碳代谢相关的特定代谢途径的碳氮比结构。多元分析表明，与微生物分类学相比，功能基因的组成变化在环境梯度上更为明显，即使在属级水平上也是如此，这表明功能多样性适应于局部环境。与含氧沉积物相比，缺氧区（即死区）的基因组成差异更大。
本研究强调了底栖功能基因如何在空间距离和环境梯度以及资源可用性上进行结构构建，并表明例如氧气、盐度以及碳氮含量的变化将影响底栖生境中的功能代谢途径。视频摘要。
