Soil salinization has rapidly encroached from the coastline to inland areas over the past two decades in the Yellow River Delta (YRD). Soil samples were collected from low‐ (LSW), medium‐ (MSW), and high‐ (HSW) salinity wetlands at a depth of 0–20 cm for 16S rRNA sequencing and bioinformatic analyses. The richness and α‐diversity indices were significantly lower in saline soils (ECe > 15 dS/m, HSW) than in soils those were not saline (ECe < 15 dS/m, LSW and MSW) (p < 0.05), generally showing a decreasing trend with increasing salinities. The phyla, Proteobacteria, Bacteroidetes, Chloroflexi, Acidobacteria and Planctomycetes, represented more than 70% of the bacterial community in the three wetlands, indicating the wide adaption of these phyla to salinity changes. Specifically, Proteobacteria was recognized as the most dominant (35.30% ‐ 38.59%) phylum regardless of salinity. Furthermore, bacterial composition was different among the wetlands, as revealed by β‐diversity indices and analysis of similarities. Linear discriminant analysis (LDA) effect size revealed the presence of 11, 2, and 10 discriminating bacterial taxa (LDA > 4) among LSW, MSW, and HSW, respectively, implying that they can serve as bioindicators of soil salinization. Redundancy analysis, Spearman correlation analysis, and the Mantel test suggested that salinity parameters (EC, Na⁺, K⁺, Mg²⁺, Ca²⁺, Cl⁻, and SO₄²⁻) prominently structured the bacterial community in the current study. These results suggest that the changes of bacterial composition would be induced in these LSW and MSW soils once seawater intrusion occurs.

中文翻译：

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黄河三角洲土壤细菌群落沿盐度梯度的变化

在过去的二十年中，黄河三角洲（YRD）的土壤盐渍化迅速从海岸线侵蚀到内陆地区。从低（LSW），中（MSW）和高（HSW）盐度湿地收集土壤样品，深度为0–20 cm，以进行16S rRNA测序和生物信息学分析。盐渍土（ECe> 15 dS / m，HSW）的丰富度和α多样性指数显着低于非盐渍土（ECe <15 dS / m，LSW和MSW）（p <0.05），通常显示随着盐度增加而下降的趋势。在三个湿地中，门，变形杆菌，拟杆菌，绿弯曲菌，嗜酸杆菌和扁平菌占70％以上的细菌群落，表明这些门对盐度变化的广泛适应性。特别是，无论盐度如何，变形杆菌都被认为是最主要的门类（35.30％-38.59％）。此外，如β-多样性指数和相似性分析所揭示，湿地之间的细菌组成也不同。线性判别分析（LDA）的效果大小表明，在LSW，MSW和HSW中分别存在11、2和10个区分细菌的类群（LDA> 4），这表明它们可以用作土壤盐渍化的生物指标。冗余分析，Spearman相关分析，⁺，K ⁺，Mg的²⁺，钙²⁺，氯^-和SO ₄ ^2-）突出地构成的细菌群落在目前的研究。这些结果表明，一旦海水入侵，将在这些LSW和MSW土壤中诱导细菌组成的变化。