摘要
三峡大坝建设显著改变了长江水沙通量,但其对沉积物中微生物介导的多功能性(碳、氮、磷循环)的影响尚未明确。本研究基于16S扩增子测序、共现网络分析和结构方程模型,探究三峡大坝对上下游沉积物细菌群落组成、多样性及多功能性的影响。结果表明,上游沉积物细菌群落以假单胞菌门(约25.5%)为主,下游以脱硫杆菌门(约24.8%)为主。三峡大坝显著降低了下游沉积物的细菌α多样性,且α多样性与水分(减少约35.39%)、阳离子交换量(减少约49.64%)和溶解性有机碳(减少约49.88%)的减少显著相关。结构方程模型显示,沉积物细菌α多样性通过削弱细菌网络相互作用显著降低沉积物多功能性。本研究揭示了三峡大坝对下游沉积物生态功能的影响,建议通过长期监测沉积物中溶解性有机碳和阳离子交换量,以优化水文管理,减缓生物多样性损失。
The construction of the Three Gorges Dam has had a considerable effect on the water and sediment fluxes in the Yangtze River,yet the impact on microbially mediated multifunctionality(carbon,nitrogen,and phosphorus cycling)in sediments remains to be elucidated.The present study employed 16S amplicon sequencing,co-occurrence network analysis,and structural equation modelling to investigate the effects of the dam on bacterial community composition,diversity,and multifunctionality in upstream and downstream sediments.The results of the study indicated that upstream sediments were predominantly composed of Proteobacteria(about 25.5%),while downstream sediments exhibited a preponderance of Desulfobacterota(about 24.8%).The construction of the dam resulted in a substantial reduction in bacterialα-diversity in the downstream sediments.This reduction was closely correlated with decreases in moisture content(about 35.39%),cation exchange capacity(about 49.64%),and dissolved organic carbon(about 49.88%).The findings of structural equation modeling suggested that a decrease inα-diversity directly impaired ecological functions and indirectly reduced multifunctionality by weakening bacterial network interactions.The present study underscores the ecological ramifications of the Three Gorges Dam on downstream sediment functions and puts forward the recommendation of long-term monitoring of dissolved organic carbon and cation exchange capacity,in conjunction with optimized reservoir management,as a means of mitigating biodiversity loss.
作者
郑开凯
彭春兰
高千红
严海涛
闫金波
Zheng Kaikai;Peng Chunlan;Gao Qianhong;Yan Haitao;Yan Jinbo(Three Gorges Hydrology and Water Resources Survey Bureau,Hydrology Bureau of Yangtze Water Resources Commission,Yichang 443000,P.R.China)
出处
《湖泊科学》
北大核心
2026年第1期184-192,共9页
Journal of Lake Sciences
基金
长江水利委员会水文局科技创新基金项目(SWJ-24CJX05)资助。
关键词
三峡大坝
沉积物
物质循环
细菌群落组成
生态多功能性
Three Gorges Dam
sediment
material circulation
bacterial community
ecological multifunctionality
