【目的】蓝细菌在贫瘠土壤的固氮、固碳中发挥着重要作用,然而土壤盐渍化对蓝细菌多样性及群落结构的影响还不清楚。本研究以莱州湾南岸及黄河口海水入侵盐渍化土壤为例,研究蓝细菌的多样性、群落结构及丰度沿盐度梯度的分布情况。【方法】利用自动核糖体间隔基因分析(ARISA)技术与群落相似性分析(ANOSIM)探究蓝细菌群落的差异与空间分布格局;通过16S r RNA基因克隆文库、测序与系统进化分析解析了3个典型盐度梯度样品中蓝细菌的群落组成;实时定量PCR测定蓝细菌16S r RNA拷贝数(丰度);BEST多元分析探寻影响蓝细菌分布的主要环境因子。【结果】蓝细菌在莱州湾南岸盐土中分布广泛,其群落结构在低(0.63%-1.27%)、中(1.55%-2.00%)、高盐度(2.39%-5.11%)样品组之间差异显著(P=0.03),而在不同含水量样品组间则不显著(P=0.09)。总体来看,群落结构主要受土壤盐度与含水量这两个因子联合控制(P=0.02)。低盐样品中蓝细菌多样性和丰富度最低,并以Halomicronema和Acaryochloris为优势类群。Leptolyngbya在中、高盐土中占优势。Arthrospira与Geitlerinema仅在低盐土中检测到,而Oscillatoria则仅出现在高盐土中。随盐度升高蓝细菌丰度呈下降趋势,低盐土样中蓝细菌丰度(2.14×105 copies/g干土)显著高于中盐土(1.25×105 copies/g干土)(P<0.05);高盐度土为1.20×105 copies/g干土。【结论】盐渍化程度是调控莱州湾南岸滨海土壤中蓝细菌群落结构与丰度的最重要环境因子,可能对滨海土壤微生物碳氮循环产生重要影响。 【Objective】 Cyanobacteria play an important role in nitrogen fixation and carbon sequestration in poor soil. However, the influence of soil salinization on the diversity and community structure of cyanobacteria is still unclear. In this study, the invasion of salinized soil into the southern coast of Laizhou Bay and the Yellow River Estuary was taken as an example to study the distribution of cyanobacteria diversity, community structure and abundance along the salinity gradient. 【Method】 The differences and spatial distribution patterns of cyanobacteria community were explored by using ARISA and ANOSIM. Three 16S rRNA gene clones, sequencing and phylogenetic analysis were used to analyze three The composition of cyanobacteria in typical salinity gradient samples was determined by real-time quantitative PCR. The 16S rRNA copy number (abundance) of cyanobacteria was determined by real-time quantitative PCR. BEST Multivariate Analysis was used to explore the major environmental factors affecting the distribution of cyanobacteria. 【Result】 Cyanobacteria were widely distributed in the saline soil on the southern bank of Laizhou Bay. The community structure of cyanobacteria was between low (0.63% -1.27%), medium (1.55% -2.00%) and high salinity (2.39% -5.11%) samples The difference was significant (P = 0.03), but not significant in different water content samples (P = 0.09). Overall, the community structure is mainly controlled by the combination of soil salinity and water content (P = 0.02). The cyanobacteria had the lowest diversity and richness in low salt samples, and Halomicronema and Acaryochloris were the dominant groups. Leptolyngbya is dominant in medium and high salinities. Arthrospira and Geitlerinema were detected only in low saline soils, whereas Oscillatoria only appeared in high salt soils. With the increase of salinity, the abundance of cyanobacteria decreased. The abundance of cyanobacteria (2.14 × 105 copies / g dry soil) in low saline soil was significantly higher than that of medium salt soil (1.25 × 105 copies / g dry soil) (P < 0.05); high-salinity soil 1.20 × 105 copies / g dry soil. 【Conclusion】 Salinization is the most important environmental factor that regulates the structure and abundance of cyanobacteria in coastal soils of southern Laizhou Bay, which may have an important impact on the microbial carbon and nitrogen cycling in coastal waters.