富营养化湖泊底泥微生物对多溴联苯醚污染的响应-反馈机制

Polybrominated diphenyl ethers (PBDEs), an emerging class of persistent organic pollutants, cause serious threats to the health of aquatic environment and ecosystem. Study on the responses and feedback of microorganisms in eutrophic lake sediments to PBDE contamination has important scientific value and innovative significance to evaluate the ecological effect and pollution risk in the aquatic environment. In this project, Taihu Lake as a classical eutrophic lake was investigated by field and indoor experiments, with the different concentrations of nitrogen and phosphorus nutrient as the major environmental change condition. This project aims to (i) clarify the spatial, temporal, multimedia distribution and occurrence form of PBDEs, (ii) analyze the response process of microorganisms in sediments to PBDEs and the mechanism behinds, (iii) identify the microbial communities, enzymes and genes related to PBDE feedback regulation and create the response-feedback molecular network in eutrophic lake contaminated by PBDEs, and (iv) discuss the hazard evaluation method for lake micro-ecosystem, which will provide the basic theory and scientific support for evaluating PBDE effects on the safety of aquatic environment and developing the organic pollutant control and restoration.

多溴联苯醚(polybrominated diphenyl ethers, PBDEs)作为一种新型持久性有机污染物严重威胁水环境和水生态系统健康。富营养化湖泊底泥微生物对PBDEs污染的响应及反馈调控研究对于评判污染物在水环境中的生态效应和污染风险具有重要科学价值。本项目拟以典型富营养化湖泊—太湖为研究对象，以水体不同氮磷含量为主导变化环境条件，结合现场调查和室内试验，查明PBDEs在太湖底泥中的多介质分布特征及赋存形态，分析PBDEs污染压力下底泥微生物的响应规律及内在机制，辨识参与PBDEs反馈调控的关键微生物种群、酶类和基因，构建富营养化湖泊底泥微生物对PBDEs污染的响应-反馈调控分子网络，并探讨多种环境因素协同作用下PBDEs污染对富营养化湖泊微生态系统危害评判方法，为正确评估PBDEs对湖泊水环境安全的影响、积极开展湖泊有机污染治理和修复提供基础理论和科学支撑。

多溴联苯醚(PBDEs)作为一种新型持久性有机污染物，已在湖泊等水环境中广泛检出。研究富营养化湖泊底泥微生物对PBDEs污染的响应及反馈机制对于评判污染物在水环境中的生态效应和污染风险具有重要科学价值。本项目以典型富营养化湖泊—太湖为研究对象，结合现场调查和室内试验，查明了PBDEs在太湖底泥中的分布特征，辨识了参与PBDEs降解的关键微生物类群，解析了特异性降解菌对PBDEs的原位降解潜力，揭示了底泥不同微生物类群（细菌、真核微生物、反硝化细菌、磷矿化细菌、硫还原菌）对PBDEs的响应规律。取得的主要结果如下：（1）PBDEs在太湖不同湖区沉积物中都有检出，竺山湾污染浓度最高，十溴联苯醚浓度显著高于其他同系物（浓度范围在9.04至785 ng/g）；（2）卤代呼吸微生物是太湖沉积物中参与PBDEs厌氧还原脱溴降解的关键微生物类群，其中Dehalogenimonas是卤代呼吸微生物的优势属；（3）PBDEs污染显著改变了沉积物中细菌和真核微生物的多样性和群落组成，影响了微生物的种间互作关系，增强了不同物种间的竞争关系；（4）沉积物中物质循环相关的功能微生物类群对PBDEs响应取决于污染物的浓度和处理时间，高浓度处理下PBDEs提高了磷矿化微生物和硫还原细菌的活性、丰度和多样性，但对反硝化细菌的丰度和活性具有显著抑制作用，不同基因型的功能微生物对PBDEs响应的敏感程度差异明显。项目成果为评估PBDEs对湖泊微生态系统的影响、开展湖泊有机污染生物修复提供了科技支撑。