Department of Organismic and Evolutionary Biology, Harvard University, 16 Divinity Ave., Cambridge, MA, 02138, USA.
United States Department of Energy, Joint Genome Institute, 2800 Mitchell Dr, Walnut Creek, California, 94598, USA.
FEMS Microbiol Lett. 2020 Jan 1;367(1). doi: 10.1093/femsle/fnaa031.
Interactions among microorganisms and their mineralogical substrates govern the structure, function and emergent properties of microbial communities. These interactions are predicated on spatial relationships, which dictate metabolite exchange and access to key substrates. To quantitatively assess links between spatial relationships and metabolic activity, this study presents a novel approach to map all organisms, the metabolically active subset and associated mineral grains, all while maintaining spatial integrity of an environmental microbiome. We applied this method at an outgassing fumarole of Vanuatu's Marum Crater, one of the largest point sources of several environmentally relevant gaseous compounds, including H2O, CO2 and SO2. With increasing distance from the sediment-air surface and from mineral grain outer boundaries, organism abundance decreased but the proportion of metabolically active organisms often increased. These protected niches may provide more stable conditions that promote consistent metabolic activity of a streamlined community. Conversely, exterior surfaces accumulate more organisms that may cover a wider range of preferred conditions, implying that only a subset of the community will be active under any particular environmental regime. More broadly, the approach presented here allows investigators to see microbial communities 'as they really are' and explore determinants of metabolic activity across a range of microbiomes.
微生物及其矿物基质之间的相互作用控制着微生物群落的结构、功能和涌现特性。这些相互作用取决于空间关系，空间关系决定了代谢物的交换和关键基质的获取。为了定量评估空间关系和代谢活性之间的联系，本研究提出了一种新方法来绘制所有生物体、代谢活跃亚组和相关矿物颗粒的图谱，同时保持环境微生物组的空间完整性。我们在瓦努阿图的马鲁姆火山口的一个喷气泉中应用了这种方法，马鲁姆火山口是包括 H2O、CO2 和 SO2 在内的几种与环境相关的气态化合物的最大点源之一。随着与沉积物-空气表面和矿物颗粒外边界的距离增加，生物体的丰度减少，但代谢活跃生物体的比例通常增加。这些受保护的小生境可能提供更稳定的条件，促进流线型群落的持续代谢活性。相反，外表面积累了更多的生物体，这些生物体可能覆盖了更广泛的优选条件，这意味着在任何特定的环境条件下，只有群落的一部分会活跃。更广泛地说，这里提出的方法使研究人员能够“真实地”看到微生物群落，并探索一系列微生物群落中代谢活性的决定因素。
