冰封期内蒙古南海湖细菌菌群结构特征分析

Structure of Bacteria Community in the Nanhai Lake at Frozen

【目的】探究寒旱区湖泊冰封期细菌菌群结构特征及影响因素。【方法】采用高通量测序技术对南海湖不同湖区12个采样点水体及沉积物细菌进行测定,分析了多样性指数、细菌群落组成并进行了相关性热图分析。【结果】不同区域物种多样性有一定差异。从门水平来看,细菌主要为变形菌门(Proteobacteria)、绿弯菌门(Chloroflexi)、蓝藻门(Cyanobacteria)、拟杆菌门(Bacteroidetes)和放线菌门(Actinobacteria)。沉积物中以变形菌门(40%)和绿弯菌门(24%)居多,水体中以蓝藻门(29%)和放线菌门(33%)居多,菌群丰度在旅游开发区较大。从属水平分析,优势类群集中在硫杆菌属(thiobacillus)、未分类蓝细菌科(unclassified-c-Cyanobacteria)、未分类绿弯菌科(unclassified-p-Chloroflexi)。沉积物中以硫杆菌属居多,约占21%,水体中以未分类蓝细菌科居多,约占24%,其在4个区域均有大量分布,旅游开发区最多。TN、DO、T(温度)对水体细菌群落结构影响较大,TN、NH_4^+-N、C/N对沉积物细菌群落结构影响较大,控制其量是控制南海湖水华爆发的重要条件。【结论】南海湖在冰封期富营养化加剧,在各区域沉积物中均有Thiobacillus,其在南海湖冰封期的生物地球化学循环中扮演着重要的角色,对预防黑臭水体发生具有重要作用。

【Objective】Change in structure of microbial community could alert functions of an aquatic ecosystem,and this paper analyses the bacterial communities at Nanhai lake in Baotou when it was frozen.【Method】Bacteria in samples taken from both water and sediments from 12 sites across the lake were sequenced using the high-throughput sequencing,and the data was then analysed using the correlation thermogram.【Result】Bacterial diversity varied between the sampling sites.At the phylum level,Proteobacteria,Chloroflexi,Cyanobacteria,Bacteroidetes and Actinobacteria were most abundant,with the number of Proteobacteria and Chloroflexi much higher than others in the sediment,while Cyanobacteria(29%)and Actinobacteria(33%)were more dominant than others in the water;it was also found that the abundance of bacteria was higher in areas popular to tourists.At genus level,Thiobacillus,norank-f-anaerolineaceae,unclassified-p-Chloroflexi were dominant,with Thiobacillus 21%higher in the sediment and norank-f-anaerolineaceae 24%higher in the water.The redundancy analysis for relationship between bacterial communities and environmental factors revealed that total nitrogen(TN),dissolved oxygen and temperature had the greatest influence on structure of the bacterial community in the water,while TN,NH4+-N and COD impacted the bacteria community structure in the sediment more.As such,controlling contents of these elements is critical to avoid outbreak of bloom in the lake.【Conclusion】There has been an increase in eutrophication in Nanhai Lake in winter when the lake is frozen,and Thiobacillus found in the sediment across the lake plays an important role in biogeochemical cycles of sediments.Its control is hence critical to keep the lake from becoming black and odorous.