Sulphate-reducing bacteria (SRB) represent a key biological component of the global sulphur (S) cycle and are common in soils, where they reduce SO₄²⁻ to H₂S during the anaerobic degradation of soil organic matter. The factors that regulate their distribution in soil, however, remain poorly understood. We sought to determine the ecological patterns of SRB richness within a nationwide 16S metabarcoding dataset. Across 436 sites belonging to seven contrasting temperate land uses (e.g., arable, grasslands, woodlands, heathland and bog), SRB richness was relatively low across land uses but greatest in grasslands and lowest in woodlands and peat-rich soils. There was a shift in dominant SRB taxa from Desulfosporosinus and Desulfobulbus in arable and grassland land uses to Desulfobacca in heathland and bog sites. In contrast, richness of other generalist anaerobic bacterial taxa found in our dataset (e.g., Clostridium, Geobacter and Pelobacter) followed a known trend of declining richness linked to land-use productivity. Overall, the richness of SRBs and anaerobes had strong positive correlations with pH and sulphate concentration and strong negative relationships with elevation, soil organic matter, total carbon and carbon-to-nitrogen ratio. It is likely that these results reflect the driving influence of pH and competition for optimal electron acceptors with generalist anaerobic bacteria on SRB richness.

中文翻译：

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温带土壤中土地利用的 pH 值驱动了通才厌氧菌和硫酸盐还原菌的分离丰富度

硫酸盐还原菌 (SRB) 是全球硫 (S) 循环的关键生物成分，在土壤中很常见，它们在土壤有机质厌氧降解过程中将SO ₄ ^2-还原为 H ₂ S。然而，调节它们在土壤中分布的因素仍然知之甚少。我们试图在全国性的 16S 元条形码数据集中确定 SRB 丰富度的生态模式。在属于七个不同温带土地用途（例如，耕地、草地、林地、荒地和沼泽）的 436 个地点中，SRB 丰富度在土地用途中相对较低，但在草地中最高，在林地和富含泥炭的土壤中最低。主要 SRB 分类群从Desulfosporosinus和Desulfobulbus发生转变在可耕地和草地上用于荒地和沼泽地中的脱硫杆菌。相比之下，在我们的数据集中发现的其他通才厌氧细菌类群（例如，梭状芽孢杆菌、地杆菌和Pelobacter）的丰富度遵循与土地利用生产力相关的丰富度下降的已知趋势。总体而言，SRBs 和厌氧菌的丰富度与 pH 值和硫酸盐浓度呈强正相关，与海拔高度、土壤有机质、总碳和碳氮比呈强负相关。这些结果很可能反映了 pH 值的驱动影响以及与通用厌氧细菌对最佳电子受体的竞争对 SRB 丰度的影响。