宏组学技术探究海洋环境微生物群落对典型环烷酸污染的响应机制

Marine naphthenic acid pollution has been an unavoidable environmental problem while there were few researches on the influence of it on the marine micro-ecology. In this project, firstly, we selected the seawater and sediments from the polluted areas and non-polluted areas of the Bohai Reservoir and their physicochemical property will be determined. Through the method of metagenomic and metatranscriptomic, we will study the metabolic network of microbial communities in two different regions at the expression level; find the dominant metabolic pathways and find out the key biological processes and metabolic pathways for the metabolism of naphthenic acids. Secondly, the spatio-temporal character of the microbial communities between the polluted areas and non-polluted areas will be compared to illustrate the community succession pattern in these two areas. The difference of key genes and expression of mRNA resulted from the naphthenic acid pollution will be detected. According to the cluster analysis, the differences of population structure in different environments will be analyzed. At last, we will clarify the distribution pattern of the microbial community in the contaminated area and the relationship between the microbial community composition and environmental factors. The molecular mechanism of microbial response to naphthenic acid stress will be illuminated through this study and it will also provide important scientific data support for marine ecological risk assessment of naphthenic acid pollutants.

海洋环烷酸污染已经是一个不可回避的环境问题，但是环烷酸对海洋微生态影响的机理目前尚不清楚。本项目以渤海油藏污染区和非污染区的海水及水底沉淀物为研究对象，首先通过化学检测法测定水体及沉淀物的理化性质。其次，利用宏基因组和宏转录组学的分析方法，探究环烷酸污染海域微生物群落结构组成和时空分布特征，比较非污染区及污染区微生物群落分布的时空差异，研究非污染区至污染区海域微生物群落演替规律，进而甄别环烷酸污染诱导的微生物关键基因及其在mRNA水平上表达的差异。最终，明晰油藏区域微生物的时空分布规律，揭示渤海油田环烷酸污染海域环境微生物群落组成及其与环境因子间关系，阐明环烷酸胁迫下微生物响应的分子机制，为环烷酸类污染物的海洋生态风险评估提供重要科学数据支持。

高酸原油中典型污染物环烷酸（NAs）的大范围泄露使海洋生态系统面临长期污染的风险。本项目的开展致力对典型高酸原油高风险污染海域的水体进行探究，利用16s rDNA和宏基因组测序技术：调查微生物群落的时空分布和功能特征，探究微生物群落对溢油污染及处理的响应，阐明高酸原油及其关键污染物质环烷酸的污染修复过程中群落演替和生物降解的分子机制。结果表明：1.高风险区微生物群落中降解烷烃、烯烃、芳香烃和脂肪酸等的基因的总丰度显著高于低风险区，但基础代谢过程基因富集程度低，表明高酸原油污染物在增强微生物对其降解能力的同时破坏了其原有的生存模式。2.研究随后进行了原位微生态系统的模拟实验，以期探究微生物群落对溢油污染及处理过程的响应。土著微生物群落对石油烃、氮、磷等环境因子的变化敏感。除了加快细菌群落的演替速度，分散剂对细菌群落的结构和降解功能的影响程度明显强于石油。同时，较高剂量的石油暴露对应着更少的高相对丰度的优势菌。3.研究发现胶州湾近岸海域表层海水中的微生物在三周后能够降解70.72%的NAs (HCOWAF组). 并根据期间微生物群落结构的变化确定了与生物降解有关潜力物种， Roseobacter，Colwellia，Cycloclasticus，Sulfitobacter 和 Marivita 属依然是常见的碳氢化合物降解菌属，而 Glaciecola， Dokdonia 和 Lentibacter属更有希望应用在长期的NAs生物降解中。 芳香族化合物和烷烃类的降解更早被激活，Benzoate 和 Fatty acid degradation等与NAs降解相关的代谢途径和功能基因的丰度也随之增加。本研究为探究高酸原油污染高风险海域表层水微生物的时空分布规律；明确环境微生物群落组成及其与环境因子间关系提供科研基础，为筛选石油降解的关键细菌和评估石油泄漏给海洋生态系统带来的风险提供了信息。同时初步揭示了海洋微生物降解NAs的代谢途径及功能基因差异，并将有助于改善石油污染生物修复的应用和实践。