Abstract：
The degradation of freshwater systems by salt pollution is a threat to global freshwater resources. Salinization is commonly identified by increased specific conductance (conductivity), a proxy for salt concentrations. However, conductivity fails to account for the diversity of salts entering freshwaters and the potential implications this has on microbial communities and functions. We tested 4 types of salt pollution-MgCl2, MgSO4, NaCl, and Na2SO4-on bacterial taxonomic and functional α-, β-diversity of communities originating from streams in two distinct localities (Nebraska [NE] and Ohio [OH], USA). Community responses depended on the site of origin, with NE and OH exhibiting more pronounced decreases in community diversity in response to Na2SO4 and MgCl2 than other salt amendments. A closer examination of taxonomic and functional diversity metrics suggests that core features of communities are more resistant to induced salt stress and that marginal features at both a population and functional level are more likely to exhibit significant structural shifts based on salt specificity. The lack of uniformity in community response highlights the need to consider the compositional complexities of salinization to accurately identify the ecological consequences of instances of salt pollution.
摘要：
盐污染造成的淡水系统退化是对全球淡水资源的威胁。盐碱化通常通过增加比电导(电导率)来识别，盐浓度的代表。然而,电导率未能说明进入淡水的盐的多样性以及这对微生物群落和功能的潜在影响。我们测试了4种类型的盐污染-MgCl2，MgSO4，NaCl，和Na2SO4-关于细菌分类学和功能α-，源自两个不同地区（内布拉斯加州[NE]和俄亥俄州[OH]，美国）。社区的反应取决于产地，与其他盐改良剂相比，NE和OH对Na2SO4和MgCl2的响应表现出更明显的群落多样性下降。对分类学和功能多样性指标的仔细检查表明，群落的核心特征对诱导的盐胁迫更具抵抗力，并且在种群和功能水平上的边缘特征更有可能表现出基于盐特异性的显着结构变化。社区反应缺乏统一性，这凸显了需要考虑盐碱化的成分复杂性，以准确识别盐污染实例的生态后果。
