Orel Neža, Fadeev Eduard, Klun Katja, Ličer Matjaž, Tinta Tinkara, Turk Valentina
Marine Biology Station Piran, National Institute of Biology, Piran, Slovenia.
Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria.
Front Microbiol. 2022 Jan 17;12:765091. doi: 10.3389/fmicb.2021.765091. eCollection 2021.
Coastal zones are exposed to various anthropogenic impacts, such as different types of wastewater pollution, e.g., treated wastewater discharges, leakage from sewage systems, and agricultural and urban runoff. These various inputs can introduce allochthonous organic matter and microbes, including pathogens, into the coastal marine environment. The presence of fecal bacterial indicators in the coastal environment is usually monitored using traditional culture-based methods that, however, fail to detect their uncultured representatives. We have conducted a year-around survey of the pelagic microbiome of the dynamic coastal ecosystem, subjected to different anthropogenic pressures to depict the seasonal and spatial dynamics of traditional and alternative fecal bacterial indicators. To provide an insight into the environmental conditions under which bacterial indicators thrive, a suite of environmental factors and bacterial community dynamics were analyzed concurrently. Analyses of 16S rRNA amplicon sequences revealed that the coastal microbiome was primarily structured by seasonal changes regardless of the distance from the wastewater pollution sources. On the other hand, fecal bacterial indicators were not affected by seasons and accounted for up to 34% of the sequence proportion for a given sample. Even more so, traditional fecal indicator bacteria () and alternative wastewater-associated bacteria (, , and ) were part of the core coastal microbiome, i.e., present at all sampling stations. Microbial source tracking and Lagrangian particle tracking, which we employed to assess the potential pollution source, revealed the importance of riverine water as a vector for transmission of allochthonous microbes into the marine system. Further phylogenetic analysis showed that the in our data set was affiliated with the pathogenic , suggesting that a potential exposure risk for bacterial pathogens in anthropogenically impacted coastal zones remains. We emphasize that molecular analyses combined with statistical and oceanographic models may provide new insights for environmental health assessment and reveal the potential source and presence of microbial indicators, which are otherwise overlooked by a cultivation approach.
沿海地区受到各种人为影响，例如不同类型的废水污染，如经处理的废水排放、污水系统泄漏以及农业和城市径流。这些不同的输入源可将包括病原体在内的外来有机物质和微生物引入沿海海洋环境。沿海环境中粪便细菌指标的存在通常使用基于传统培养的方法进行监测，然而，这些方法无法检测到未培养的细菌。我们对动态沿海生态系统的浮游微生物组进行了为期一年的调查，该生态系统受到不同的人为压力，以描绘传统和替代粪便细菌指标的季节和空间动态。为了深入了解细菌指标生长旺盛的环境条件，我们同时分析了一系列环境因素和细菌群落动态。对16S rRNA扩增子序列的分析表明，无论与废水污染源的距离如何，沿海微生物组主要由季节变化构成。另一方面，粪便细菌指标不受季节影响，在给定样本的序列比例中占比高达34%。更重要的是，传统粪便指示菌（）和与废水相关的替代细菌（、、和）是沿海核心微生物组的一部分，即在所有采样站均有出现。我们采用微生物源追踪和拉格朗日粒子追踪来评估潜在污染源，结果表明河水作为外来微生物进入海洋系统的传播载体具有重要意义。进一步的系统发育分析表明，我们数据集中的与致病性相关，这表明在受人为影响的沿海地区，细菌病原体存在潜在的暴露风险。我们强调，分子分析与统计和海洋模型相结合可为环境健康评估提供新的见解，并揭示微生物指标的潜在来源和存在情况，而这些在培养方法中往往被忽视。
