摘要
高海拔冰川生态系统是响应全球气候变化的敏感指示器,色林错作为青藏高原最大的冰川补给内流湖,其水体微生物群落作为生物多样性与生态功能的核心载体,对维系系统稳定至关重要。为揭示色林错细菌群落多样性格局及其群落构建机制,预测细菌群落对高寒生态系统变化的响应,本研究于2022年6月环色林错一周进行了采样,利用16S rRNA基因高通量测序技术,分析了色林错水体细菌群落的组成和结构,并测定了水环境因子。结果表明,色林错水体细菌群落具有较高的分类和代谢多样性,测序得到的1327612条高质量序列被聚类为8587个OTU,涵盖28门98属,其中变形菌门(Proteobacteria)、拟杆菌门(Bacteroidota)和放线菌门(Actinomycetota)为优势门类。不同区域间细菌群落α多样性指数无显著差异,细菌群落丰富度沿南岸—北岸—入水口区域顺序逐渐增大,多样性逐渐升高。β多样性分解表明,群落间物种组成差异主要由物种周转过程引起。共现网络分析显示,细菌群落间以正相关关系为主,表明群落间存在协同作用。中性群落模型和C-score分析表明,色林错细菌群落构建过程主要由确定性过程主导。在确定性过程中,pH、总溶解固体(TDS)和浊度是影响色林错细菌群落生态位宽度值的主要环境因子。本研究为理解色林错水体细菌群落的生态特征及其对环境变化的响应提供了重要科学依据。
High-altitude glacial ecosystems serve as sensitive indicators of global climate change.Within these systems,aquatic microbial communities,acting as core carriers of biodiversity and ecological function,are cru⁃cial for maintaining ecosystem stability.Selin Co,the largest glacier-fed endorheic lake on the Qinghai-Xizang Plateau,provides a unique environment that serves as an ideal platform for investigating the ecological patterns of microbial communities under extreme conditions.This study focused on analyzing the diversity patterns and assembly mechanisms of bacterial communities in the waters of Selin Co Lake and assessing their potential re⁃sponse dynamics to environmental changes.Systematic sampling was conducted in June 2022 at the south shore,north shore,and main inflow of Selin Co.Key physicochemical parameters,including pH,total dissolved sol⁃ids(TDS),turbidity(TUR),and nutrients,were measured concurrently.Using 16S rRNA gene high-through⁃put sequencing,the bacterial community composition and structure were deeply analyzed,yielding a total of 1327612 high-quality sequences clustered into 8587 operational taxonomic units(OTUs),spanning 28 phyla and 98 genera,thereby revealing exceptionally high taxonomic diversity.Community structure analysis showed that Proteobacteria,Bacteroidota,and Actinomycetota were the absolutely dominant phyla,with Loktanella,Belliella,and Aquiluna as the predominant genera at the genus level.Althoughα-diversity indices exhibited no statistically significant differences among sampling regions,richness and diversity showed an increasing spatial trend from the south shore to the north shore and inflow,indicating potential influence of local environmental heterogeneity or hydrological inputs.βdiversity decomposition(based on Bray-Curtis dissimilarity)demonstrat⁃ed that differences in bacterial community composition across the regions in Selin Co were primarily driven by species turnover rather than nestedness,reflecting strong environmental filtering or dispersal limitation.Microbi⁃al co-occurrence network analysis showed that bacterial taxa were mainly significantly positively correlated,indi⁃cating widespread cooperative interactions or niche overlap within the community.This pattern suggested that implementing“a simultaneous multi-region conservation strategy without prioritization”might be more effective for protecting aquatic microbial diversity than prioritizing specific areas.To further analyze community assem⁃bly mechanisms,this study applied both the neutral community model(NCM)and checkerboard score(Cscore)test.The results showed that deterministic processes predominated in structuring bacterial communities in Selin Co,while stochastic processes played a relatively minor role.Further linear regression modeling of the re⁃lationship between bacterial OTU niche breadth and environmental factors identified pH,TDS,and TUR as key drivers significantly influencing bacterial niche breadth.Using multiple community ecological analytical ap⁃proaches,this study systematically revealed the high diversity,spatial pattern characteristics,and assembly mechanisms of bacterial communities in Selin Co,Qinghai-Xizang Plateau.The findings provide an important case for understanding microbial biogeography in high-altitude glacial lakes,highlighting the central role of envi⁃ronmental selection in shaping microbial communities within extreme aquatic environments.More importantly,the identified key environmental driving factors(pH,TDS,TUR)are highly susceptible to regional climate changes(e.g.,accelerated input of debris from glacial retreat,altered precipitation patterns,and rising water temperatures).Therefore,the community-environment relationship model established in this study provides a solid scientific foundation for predicting the dynamic responses of microbial community structure and function in Selin Co and similar high-altitude glacial lake ecosystems under future climate change scenarios.This study holds significant scientific value for assessing the impact of global change on vulnerable alpine aquatic ecosys⁃tems and for formulating conservation strategies.
作者
薛曌
德吉
王兰
童银栋
张继峰
郭小芳
XUE Zhao;Deji;WANG Lan;TONG Yindong;ZHANG Jifeng;GUO Xiaofang(Key Laboratory of Biodiversity and Environment on the Qinghai-Tibet Plateau,Ministry of Education,School of Ecology and Environment,Xizang University,Lhasa 850000,China)
出处
《冰川冻土》
2025年第4期1099-1111,共13页
Journal of Glaciology and Geocryology
基金
国家重点研发计划政府间国际科技创新合作项目(2021YFE0113700)
西藏生态环境监测项目(GZFCG2024-23011)
西藏自治区科技计划基地与人才计划项目(XZ202501JD0019)
2025年中央财政支持地方高校改革发展专项资金项目(00061349)资助。
关键词
色林错
β多样性分解
群落构建
细菌
Selin Co
βdiversity decomposition
community assembly
bacteria
