小清河流域-河口区微生物群落对全氟化合物的响应
Alternative TitleMicrobial community response to perfluoroalkyl substances in the Xiaoqing River basin and estuary area
郭超
Subtype博士
Thesis Advisor唐建辉
2022-11-26
Training institution中国科学院烟台海岸带研究所
Degree Grantor中国科学院大学
Place of Conferral中国科学院烟台海岸带研究所
Degree Name工学博士
Degree Discipline环境科学
Keyword全氟烷基物质 微生物群落 微宇宙模拟 扩增子测序分析
Abstract全/多氟烷基物质(Perandpolyfluoroalkylsubstances, PFAS)是一类碳链上的氢原子部分或全部被氟原子取代的有机化合物,被广泛应用于不同行业领域,并因此成为一种在环境中广泛分布的有机污染物。微生物群落是自然生态系统的基石,在物质循环和能量流动等维持生态系统稳定的过程中发挥着不可或缺的作用。目前,关于PFAS污染背景下的微生物群落的响应研究认识不足,缺乏对不同季节、栖息环境和不同PFAS污染浓度下微生物群落变异差异性的综合考虑。同时,实验室模拟体系相比原位环境过于简化,并且少有对水体中的颗粒附着态菌群和游离态菌群开展的研究。本论文通过扩增子测序技术,从PFAS污染点源周边的微生物群落变异、实验室模拟细菌群落在全氟辛酸(Perfluorocaprylicacid, PFOA)污染下的变异及河口区域对模拟体系中的生物标志类群进行验证共三个方向进行了相关研究,相关结果有助于增强对PFAS影响下微生物群落变异的认知。本文的主要研究结果包括: (1)对典型PFAS点源区域的微生物群落变异情况进行了全面的分析,明确了季节变化会使微生物群落对PFAS污染产生差异性的响应,不同类型的微生物群落(细菌、真菌、微真核生物)面对PFAS污染也会产生不同程度的变异。在空间尺度上,小清河污染点源上下游群落整体间无显著性差异,表明采样点周边可能存在强于PFAS的环境因子干扰。在线性判别分析中,部分生物标志类群(如:Peridiniopsis, Syncephalis)与PFAS浓度有较好的相关性。其中,在水体中的生物标志类群(如:Peridiniopsis)可能来源于氟化物制造厂污水的共排放,而沉积相中的生物标志类群(如:Syncephalis)更可能表明了PFAS污染所带来的真实环境效应。在非度量多维尺度分析中,丰水期点源上下游微生物群落相比较于枯水期有更大的差异,这表明季节变化会导致微生物群落对PFAS污染的差异性响应。在Alpha多样性分析中,水相细菌较微真核生物有更大的变异,沉积相中细菌群落在枯水期和丰水期均对PFAS污染有较高响应(存在高相对丰度的单一类群),而真菌则有较明显的季节差异。 (2)在微宇宙模拟全氟辛酸在河流、海洋环境下的传输以及对细菌群落影响的实验中发现,微宇宙实验相比简单模拟实验中的群落具有更高的稳定性。在河流、海洋模拟系统的对比中,海洋中PFOA向沉积相中的转移速度更快,群落多样性与PFOA浓度的相关性更高。在线性判别分析中,黄杆菌科(Flavobacteriacea)同时显著存在于河流与海洋的实验组系统中。因此,黄杆菌科具备成为PFOA生物标志类群的应用潜力。在时间尺度的差异分析中,某些组间显著差异属,如:Desulfoprunum, Dinghuibacter, Terrimonas等,重复出现于实小清河流域-河口区微生物群落对全氟化合物的响应II验组和空白组中,因此不具备对PFOA污染的特异指示性和代表性,而活动杆菌属(Actibacter)和沉积杆菌属(Limnobacter)具有作为高强度PFOA投入后,中长期污染下的稳定性指示菌群的潜力。 (3)河口区域的微生物群落在水相、颗粒相和游离相中均存在季节显著性差异,由季节变动带来的河水径流量和温度差异被认为是造成季节差异变化的主要原因。基于相似性百分比分析(Simper),未鉴定蓝藻属和不动杆菌属(Acinetobacter)是造成细菌群落属分类水平微生物群落结构季节差异的主要贡献者。在线性判别分析中,沉积物、颗粒附着态和游离态的细菌群落均具有独特的生物标志类群,这表明以上三种环境状态下的菌群各自具有特异性。在典型相关分析中,发现PFAS浓度对河流上游的细菌群落具有较大的解释度,这可能是由于上游站位受到的盐离子干扰较小。在对颗粒附着态细菌群落中排名前十的优势门和属进行与PFAS浓度的相关性分析中发现,丰水期细菌群落中的蓝藻细菌、变形菌门、疣微菌门、装甲菌门和林杆菌属(Alsobacter)与悬浮颗粒物中的PFAS浓度存在显著相关性;而枯水期细菌群落中的军团菌属(Legionella)和热单胞菌属(Thermomonas)与水中的PFAS浓度显著相关。这表明颗粒相中的细菌群落组成受PFAS污染影响较大。因此,在未来PFAS污染下微生物群落响应的研究中,需要对颗粒附着态菌群进行重点关注。
Other AbstractPer and polyfluoroalkyl substances (PFAS), are a group of compounds that parts or all of the hydrogen atoms in the carbon chain are replaced by fluorine atoms. They are used in a wide range of industries and are therefore widely distributed in the environment as persistent organic pollutants (POPs). Microbial communities are the cornerstone of natural ecosystems and play an essential role in maintaining the stability of the ecosystem through material and energy cycling. Currently, studies on microbial community response to PFAS contamination are still incomplete. There is a lack of comprehensive consideration of the effects between seasons, habitats, and microbial species on the variability of microbial communities under PFAS contamination. The laboratory simulation system is too simplified compared to the in-situ environment, and hard to find research focused on the particle-attached communities in the water phase. Based on the current issues in the impact of PFAS on microbial community research, this thesis investigates the variation of microbial communities in PFAS-contaminated point sources, under Perfluorooctanoic acid (PFOA) contamination in the laboratory simulations, and the validation of biomarkers from the simulations in estuarine areas. This thesis presents the results of a study on the variation of microbial communities under the influence of the PFAS point source, in laboratory simulations, and the validation of biomarkers in the estuary. The main findings of this paper are as follows:(1) A comprehensive analysis of microbial community variation in PFAS point source areas clarifies that seasonal changes cause microbial communities different responses to PFAS contamination and different types of microbial communities (bacteria, fungi, microeukaryotes) also show different responses to PFAS contamination. However, at the spatial scale, no significant differences between the upstream and downstream communities of the PFAS point source. It suggests that strong environmental factors cover the PFAS effect on community variation. In the linear discriminant analysis, some biomarkers (e.g. Peridiniopsis, Syncephalis) are well correlated with PFAS concentrations. We suggest that the biomarkers in the water phase (e.g. Peridiniopsis) may originate from the co-emissions of fluorocarbon plant waters, while biomarkers in the sediment phase (e.g. Syncephalis) are more likely to indicate real environmental effects from PFAS contamination. In Non-metric multidimensional scaling (NMDS) analyses, the microbial communities between the upstream and downstream of the point source were more variable in the wet season than in the dry season. It is necessary to include two or more seasonal samples in field studies of the effects of PFAS on environmental microbial. In the Alpha diversity analysis, bacteria showed greater variation than microeukaryotes in the water phase, and bacterial community composition in the sediment phase was stable in both the dry and wet seasons, while fungi showed more seasonal differences.(2) In microcosm simulations of PFOA transport in riverine and marine environments and effects on bacterial communities, it was found that microbial communities in microcosm experiments were more stable and tolerant than in simple simulations. In the comparison of river and sea microcosm systems, PFOA accumulates more rapidly in the sea system sediment phase. Besides, bacterial community Alpha diversity and PFOA concentrations were significantly correlated in the marine simulated system. In the linear discriminant analysis, Flavobacteriacea both significantly exist in the river and sea PFOA-added systems. It suggests Flavobacteriacea have the potential as a PFOA biomarker.In time scale difference (Metastat) analysis, some significant differences genera, e.g. Desulfoprunum, Dinghuibacter, and Terrimonas, were repeatedly shown in the experimental (PFOA added) and blank groups, and they were not specific indicators of PFOA contamination. While Actibacter and Limnobacter were suitable to become the stable middle-long-term PFOA indicators after high-level PFOA pollution.(3) The microbial community variations show seasonal difference effects in the water phase, particle-attached phase, and free-living phase. The variation of river runoff and temperature difference was considered the main reason for seasonal difference results. In the percentage of similarity analysis, a kind of Cyanobacteria and Acinetobacter were the main contributing genera to the seasonal variation in microbial community structure at the taxonomic level of the bacterial community genus. In the Lefse analysis, unique biomarkers were found in the sediment, particle-attached and free-living bacterial communities, suggesting that each of these three communities was specific and responded differently to PFAS.In Canonical Correlation Analysis (CCA) , PFAS concentrations were found to explain more of the bacterial community in the river's upper reaches. It may due to the lower salt concentrations in upstream than offshore areas. The correlation analysis of the top ten dominant phyla and genera in the particle-attached bacterial community with PFAS concentrations revealed that Cyanobacteria, Proteobacteria, Verrucomicrobia, Armatimonadetes phylum, and Alsobacter genus relative abundance were significantly correlated with suspended particulate PFAS concentrations. Besides, the phylum, Legionella, and Thermomonas in the dry season bacterial community were significantly correlated with PFAS concentrations in water. This suggests that the bacterial community composition in the particulate phase may be strongly influenced by PFAS contamination. Therefore, more attention needs to be paid to particle-attached phase bacterial communities in future studies.
Pages137
Language中文
Document Type学位论文
Identifierhttp://ir.yic.ac.cn/handle/133337/34393
Collection中国科学院海岸带环境过程与生态修复重点实验室
Recommended Citation
GB/T 7714
郭超. 小清河流域-河口区微生物群落对全氟化合物的响应[D]. 中国科学院烟台海岸带研究所. 中国科学院大学,2022.
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