九龙江浮游原核和真核微型生物群落对典型新兴污染物的生态响应机制研究

Rivers are one of the most important freshwater resources. However, the quality of riverine environment especially its biological components are seriously threatened by the "pseudo-persistence" of emerging organic contaminants (EOCs). Microorganisms (prokaryotes and eukaryotes) represent by far the most diverse and numerically predominant biota in the riverine ecosystems, and play vital roles in the biogeochemical cycles. However, the effects of EOCs on the community structure and species interactions of river microorganisms, and their responses to the EOCs are still poorly known. Through a long term monitoring of Jiulong River, Fujian province we were able to elucidate the distribution pattern of EOCs and the prokaryotic communities at the watershed scale, and the responses of the prokaryotic ecological network to EOCs pollution. The scientific hypothesis of the proposed project, based on our previous findings are: i) due to the differences of dispersal ability or metabolic plasticity between microbial prokaryotes and eukaryotes, the microbial eukaryotes are more sensitive to the EOCs pollution; ii) subsequently the changes in the ecological network of microbial eukaryotes are anticipated to be more quick under the influence of EOCs than that of the prokaryotes; iii) and consequently the interactions between microbial prokaryotic and eukaryotic species may also change. This project will carry out high-throughput analyses of the EOCs and the microbial (prokaryotic and eukaryotic) communities at field and microcosm scale for a better understanding of the responses and the feedback mechanisms of the microbial prokaryotes and eukaryotes to the prevailing EOCs levels in Jiulong River. Overall, this project will provide a theoretical reference to evaluate the overall health and a solid scientific basis to predict the evolution trend of the riverine ecosystem.

河流是最重要的淡水资源之一。新兴有机污染物具有“假”持久性和生物效应强等特点，当前已成为威胁河流生态环境的最普遍因素之一。原核、真核微型生物是河流生态系统的重要组成部分，在生物地球化学循环过程中发挥着关键作用。然而，有关新兴污染物对河流微型生物群落的影响及其响应机制尚不清楚。申请团队在福建九龙江开展了长期观测，揭示了典型新兴污染物和原核生物群落的流域分布特征、原核生物生态网络对新兴污染物的响应机制。在基础上，提出本项目的科学假说：由于扩散能力或生理可塑性的差别，河流真核微型生物对新兴污染物更敏感；使得真核微型生物生态网络对新兴污染物的响应更快、更强烈；进而导致真核与原核生物间的互作关系发生变化。项目将结合高通量污染物分析和高通量分子生物学技术，通过实地观测和微宇宙模拟，揭示河流微型生物群落在新兴污染物胁迫下的演变规律和响应机制，为河流生态系统的健康评估和演变趋势预测提供理论参考和科学依据。

河流是最重要的淡水资源之一。新兴有机污染物具有“假”持久性和生物效应强等特点，当前已成为威胁河流生态环境的最普遍因素之一。原核、真核微型生物是河流生态系统的重要组成部分，在生物地球化学循环过程中发挥着关键作用，可灵敏指征水体环境的变化。然而，有关新兴污染物对河流微型生物群落的影响及其响应机制尚不清楚。本项目在前期研究基础上，以福建地区代表性河流（九龙江、闽江等）为主要研究区域，以原核生物、微型真核生物和后生动物为研究对象，综合水质参数分析、化学新污染物分析、扩增子测序、宏基因组测序、生物信息学和多元统计等多学科技术开展了系统研究。主要取得了以下研究成果：1）发现双酚A、咖啡因、布洛芬、甲氧基肉桂酸辛酯和三氯生等化学新污染物可显著影响河流微型真核生物，揭示了化学新污染物对微型真核生物特化种的影响要强于广适种；2）发现在河流型水库中，水平尺度上化学新污染物对浮游微生物群落组成的影响效应要明显高于其在垂直尺度上的影响； 3）基于多营养级分析，初步阐明在污染程度较重区域，化学新污染物可通过影响高营养级水生生物，间接对原核生物施加影响的生态机制；4）基于室内模拟实验，揭示了痕量化学新污染物通过改变环境条件，施加环境选择压力（异质选择）来驱动浮游微生物群落发生定向演变；5）揭示了化学新污染物与微塑料联合暴露对鱼肠道微生物物种互作关系的影响效应；6）探讨了不同场景下化学新污染物对微生物新污染物（抗生素抗性基因）的潜在影响。以上研究成果揭示河流微型生物群落在新兴污染物胁迫下的演变规律和响应机制提供了理论参考和科学依据。