Comparing the benthic nitrogenase activity and diazotrophic community assembly of three large river-connected freshwater lakes in eastern China  

作　　者：Linqi Tian Ye Deng Helong Jiang 

机构地区：[1]State Key Laboratory of Lake Science and Environment,Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,China [2]CAS Key Laboratory of Environmental Biotechnology,Research Center for Eco Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China

出　　处：《Journal of Environmental Sciences》2025年第4期134-148,共15页环境科学学报(英文版)

基　　金：supported by the National Natural Science Foundation of China(Nos.51839011,42203079,and U2240208);the Carbon Peak/Neutralization Technology Innovation Project of Jiangsu Province,China(No.BK20220043);the Excellent Postdoctoral Project of Jiangsu Province,China(No.2022ZB452).

摘　　要：Biological nitrogen fixation(BNF)is a crucial process that provides bioavailable nitrogen and supports primary production in freshwater lake ecosystems.However,the characteristics of diazotrophic community and nitrogenase activity in freshwater lake sediments remain poorly understood.Here,we investigated the diazotrophic communities and nitrogenase activities in the sediments of three large river-connected freshwater lakes in eastern China using 15N-isotope tracing and nifH sequencing.The sediments in these lakes contained diverse nitrogenase genes that were phylogenetically grouped into Clusters I and III.The diazotrophic communities in the sedimentswere dominated by stochastic processes in Hongze Lake and Taihu Lake,which had heterogeneous habitats and shallower water depths,while in Poyang Lake,which had deeper water and a shorter hydraulic retention time,the assembly of the diazotrophic community in the sediments was dominated by homogeneous selection processes.Temperature and water depth were also found the key environmental factors affecting the sediment diazotrophic communities.Sediment nitrogenase activities varied in the three lakes and within distinct regions of an individual lake,ranging from 0 to 14.58 nmol/(kg·hr).Nitrogenase activity was significantly correlated with ferric iron,total phosphorus,and organic matter contents.Our results suggested that freshwater lake sediment contain high diversity of nitrogen-fixing microorganisms with potential metabolic diversity,and the community assembly patterns and nitrogenase activities varied with the lake habitat.

关 键 词：Freshwater lakes Benthic nitrogen fixation nifH gene diversity Diazotrophic assembly Null model 

分 类 号：X524[环境科学与工程—环境工程]