Wetlands are important carbon (C) sinks, yet many have been destroyed and converted to other uses over the past few centuries, including industrial salt making. A renewed focus on wetland ecosystem services (e.g., flood control, and habitat) has resulted in numerous restoration efforts whose effect on microbial communities is largely unexplored. We investigated the impact of restoration on microbial community composition, metabolic functional potential, and methane flux by analyzing sediment cores from two unrestored former industrial salt ponds, a restored former industrial salt pond, and a reference wetland. We observed elevated methane emissions from unrestored salt ponds compared to the restored and reference wetlands, which was positively correlated with salinity and sulfate across all samples. 16S rRNA gene amplicon and shotgun metagenomic data revealed that the restored salt pond harbored communities more phylogenetically and functionally similar to the reference wetland than to unrestored ponds. Archaeal methanogenesis genes were positively correlated with methane flux, as were genes encoding enzymes for bacterial methylphosphonate degradation, suggesting methane is generated both from bacterial methylphosphonate degradation and archaeal methanogenesis in these sites. These observations demonstrate that restoration effectively converted industrial salt pond microbial communities back to compositions more similar to reference wetlands and lowered salinities, sulfate concentrations, and methane emissions.

湿地是重要的碳 (C) 汇，但在过去的几个世纪中，许多湿地已被破坏并转为其他用途，包括工业制盐。重新关注湿地生态系统服务（例如，防洪和栖息地）已导致许多恢复工作，其对微生物群落的影响在很大程度上尚未探索。我们通过分析两个未恢复的前工业盐池、一个恢复的前工业盐池和一个参考湿地的沉积物核心，研究了恢复对微生物群落组成、代谢功能潜力和甲烷通量的影响。我们观察到与恢复和参考湿地相比，未恢复盐池的甲烷排放量增加，这与所有样品的盐度和硫酸盐呈正相关。16S rRNA 基因扩增子和鸟枪法宏基因组数据显示，与未恢复的池塘相比，恢复的盐池在系统发育和功能上与参考湿地更相似。古细菌产甲烷基因与甲烷通量呈正相关，编码细菌甲基膦酸降解酶的基因也是如此，这表明甲烷是由这些位点的细菌甲基膦酸降解和古细菌产甲烷产生的。这些观察结果表明，恢复有效地将工业盐池微生物群落转变为与参考湿地更相似的成分，并降低了盐度、硫酸盐浓度和甲烷排放量。