太湖湖泛常发区底泥特征及指示性细菌的研究

Characterization of Substrates and Indicator Bacteria in Flood-Prone Areas of Taihu Lake

为探究太湖湖泛常发区环境下表层底泥细菌的特点及其与环境因子的相关性,运用高通量测序的方法对太湖中湖泛常发区域以及普通水体区表层底泥细菌及环境理化指标进行检测.结果表明:①湖泛区上覆水中的TN、TP分别是普通区的2.4倍和2倍;DO(溶解氧)显著降低.②湖泛区表层底泥细菌丰度以及多样性相比普通区有显著降低(P<0.05),湖泛区4个点位(#1、#2、#3、#4)的Simpson指数均高于0.003.③从细菌门的层次来看,拟杆菌门(Bacteroidetes)在湖泛区的优势地位显著上升,#1点位已经成为第二优势菌门(占比16.3%),且随机森林分析表明拟杆菌门是两组样本之间差异性重要值最高的门类.④从属的层面来看,在湖泛区占比显著升高的Bacteroides、Bacteroidetes vadinHA17_norank、Lentimicrobiaceae_norank均为拟杆菌门下的厌氧菌属(P<0.05),同时相关性分析也表明Steroidobacteraceae_uncultured与上覆水TN、TP以及TOC含量呈显著正相关,与DO呈显著负相关.本研究为未来环境监测中增加微生物方面的测评指标存在一定的借鉴意义.

To investigate the characteristics of surface sediment bacteria and their correlation with environmental factors in the environment of the frequent lake flooding area of Taihu Lake,high-throughput sequencing was applied to detect surface sediment bacteria and environmental physicochemical indicators in the frequent lake flooding area and the common water body area of Taihu Lake.The results showed that:①TN and TP in the overlying water of the lake flood area were 2.4 times and 2 times higher than those in the common area,respectively;DO(dissolved oxygen)decreased significantly.②The abundance and diversity of bacteria in the surface sediments in the lake floodplain were significantly lower(P<0.05)than those in the common area,and the Simpson indexes of four sites(#1,#2,#3,#4)in the lake floodplain were all higher than 0.003.③From the level of bacterial phylum,the dominant position of Bacteroidetes in the lake floodplain increased significantly,and Bacteroidetes of site#1 had become the second dominant phylum(accounting for 16.3%).Random forest analysis showed that Bacteroidetes was the phylum with the highest significant difference value between the two groups of samples.④At the genus level,Bacteroides,Bacteroidetes vadinHA17_norank,and Lentimicrobiaceae_norank,which had significantly higher proportions in the lake floodplain,were all anaerobic genera under the phylum Bacteroidetes(P<0.05).At the same time,correlation analysis also showed that Steroidobacteraceae_uncultured showed a significant positive correlation with TN,TP and TOC contents of the overlying water,and showed a significant negative correlation with DO.This study has certain reference significance for adding evaluation index of microorganisms in future environmental monitoring.