Pilloni Giovanni, Bayer Anne, Ruth-Anneser Bettina, Fillinger Lucas, Engel Marion, Griebler Christian, Lueders Tillmann
Institute of Groundwater Ecology, Helmholtz Zentrum München-German Research Center for Environmental Health, 85764 Neuherberg, Germany.
Research Unit Comparative Microbiome Analysis and Research Unit Scientific Computing, Helmholtz Zentrum München-German Research Center for Environmental Health, 85764 Neuherberg, Germany.
Microorganisms. 2019 Feb 9;7(2):46. doi: 10.3390/microorganisms7020046.
Aquifers are typically perceived as rather stable habitats, characterized by low biogeochemical and microbial community dynamics. Upon contamination, aquifers shift to a perturbed ecological status, in which specialized populations of contaminant degraders establish and mediate aquifer restoration. However, the ecological controls of such degrader populations, and possible feedbacks between hydraulic and microbial habitat components, remain poorly understood. Here, we provide evidence of such couplings, via 4 years of annual sampling of groundwater and sediments across a high-resolution depth-transect of a hydrocarbon plume. Specialized anaerobic degrader populations are known to be established at the reactive fringes of the plume. Here, we show that fluctuations of the groundwater table were paralleled by pronounced dynamics of biogeochemical processes, pollutant degradation, and plume microbiota. Importantly, a switching in maximal relative abundance between dominant degrader populations within the Desulfobulbaceae and spp. was observed after hydraulic dynamics. Thus, functional redundancy amongst anaerobic hydrocarbon degraders could have been relevant in sustaining biodegradation processes after hydraulic fluctuations. These findings contribute to an improved ecological perspective of contaminant plumes as a dynamic microbial habitat, with implications for both monitoring and remediation strategies in situ.
含水层通常被视为相当稳定的栖息地，其特点是生物地球化学和微生物群落动态较低。受到污染后，含水层会转变为受干扰的生态状态，在这种状态下，专门的污染物降解菌群得以建立并介导含水层的恢复。然而，对于这类降解菌群的生态控制以及水力和微生物栖息地组成部分之间可能存在的反馈，我们仍然知之甚少。在此，我们通过对一个碳氢化合物羽流的高分辨率深度断面进行连续4年的地下水和沉积物年度采样，提供了这种耦合关系的证据。已知专门的厌氧降解菌群在羽流的反应边缘形成。在此，我们表明地下水位的波动与生物地球化学过程、污染物降解和羽流微生物群的显著动态变化并行。重要的是，在水力动态变化之后，观察到脱硫弧菌科内优势降解菌群之间的最大相对丰度发生了转变。因此，厌氧碳氢化合物降解菌之间的功能冗余可能与水力波动后维持生物降解过程有关。这些发现有助于从改进的生态学角度将污染物羽流视为动态的微生物栖息地，对现场监测和修复策略均具有启示意义。
