鄱阳湖湿地淹水与非淹水状态下微塑料表面细菌群落分布特征

Distribution Characteristics of Microplastic Surface Bacterial Communities Under Flooded and Non⁃flooded Conditions in Nanjishan Wetland of Poyang Lake

粒径小于5 mm的塑料微粒被称为微塑料,微塑料在环境中广泛存在且会造成许多负面影响.选取鄱阳湖碟形湖湿地为研究区,以碟形湖湿地淹水和非淹水状态下沉积物中的微塑料为研究对象,采集沉积物、水体以及淹水和非淹水状态下沉积物中微塑料样品.利用16S高通量测序技术分析沉积物、水体和微塑料表面细菌群落结构分布特征.α多样性分析结果表明,环境中细菌丰富度和多样性与微塑料表面存在显著差异,淹水和非淹水状态下微塑料表面细菌丰富度和多样性均低于周围环境.主坐标分析结果表明非淹水状态下微塑料表面细菌群落受沉积物影响较大,淹水状态下微塑料表面细菌群落受水体影响较大.微塑料表面细菌群落结构和周围环境亦表现出明显差异,与水体和沉积物样品相比,非淹水状态下微塑料表面变形菌门(Proteobacteria)相对丰度显著增加,而淹水状态下微塑料表面细菌拟杆菌门(Bacteroidota)相对丰度增加.沉积物中细菌主要由大量丰度<1%的其他细菌属组成,而微塑料表面细菌群落有明显优势种.非淹水状态下微塑料表面细菌属水平主要由黄杆菌属(Flavobacterium)、马赛菌属(Massilia)和假单胞菌属(Pseudomonas)组成,淹水状态下微塑料表面细菌属水平中黄杆菌属相对丰度最高.假单胞菌属是未来塑料生物降解的重点研究对象.研究可进一步提高对湖泊湿地生态系统微塑料污染的认识,并为湖泊环境管理提供理论依据.

Plastic particles smaller than 5 mm in size are known as microplastics which are widespread in the environment and can cause several negative effects.Moreover,only a few studies have focused on the relationship between microplastics and microbes in the natural wetland ecosystem.In this study,microplastics were collected from sediment,water,and sediment flooded and non⁃flooded conditions in the lake wetland of Poyang Lake as the study area.The structural distribution of bacterial community on sediment,water,and microplastics were analyzed using 16S high⁃throughput sequencing.The results of theα⁃diversity analysis showed that the bacterial abundance and diversity on the surface of microplastics were significantly different from those in the environment and were lower than those in the surrounding environment in both flooded and non⁃flooded conditions.The results of the principal co⁃ordinates analysis indicated that the bacterial community on the surface of microplastics was more influenced by the sediment in non⁃flooded conditions and by the water in flooded conditions.The structure of the bacterial community on the microplastic surface also showed significant differences from the surrounding environment,with the sediment mainly consisting of several other bacterial genera with<1%abundance,whereas the bacterial community on the microplastics had clearly dominant species.The relative abundance of Proteobacteria on the microplastic surfaces increased significantly in the non⁃flooded condition compared to that in the water and sediment samples,whereas the relative abundance of Bacteroidota on the microplastic surface increased in the flooded condition.The genus Flavobacterium,Massilia,and Pseudomonas were the most abundant in the non⁃flooded state,and the genus Flavobacterium was the most abundant in the flooded state.In this study,Pseudomonas spp.was the focus of future research on plastic biodegradation.This study can further improve the understanding of microplastic pollution in wetland ecosystems and provide a theoretical basis for lake environmental management.