Abstract Introductions of exotic plants are widespread ecological threats disturbing the carbon and nutrient cycles in global coastal wetlands. Previous studies have found that the invasion has enhanced methane emission through increased primary production and a changed methanogenic pathway. However, the previous studies did not determine the depth profiles of the changes while the depth in the soil profile to which the disturbance propagates is one of the critical issues to be addressed. In this study, we illustrated the depth profiles of the effect of the introductions of S. anglica and P. australis on the potential methane production, soil biogeochemistry, and soil microbial community which play a substantial role in enhanced methane emission due to the invasions. The in situ field measurements and anaerobic incubation were conducted to determine the mechanistic differences of depth profiles. Both introductions of S. anglica and P. australis increased methane emission through different microbial mechanisms depending on depth profile. Potential methane production was stimulated in shallow and deep soil layer of S. anglica and P. australis-introduced marshes, respectively. S. anglica increased the contribution of methylotrophic methanogenesis in top soil layers while P. australis decreased competitive inhibition by sulfate reducers in all soil layers. These results emphasize the importance of below-ground microbial activity and vertical distribution in carbon cycles in tidal marshes. Further plant invasion studies should focus on depth profiles of microbial processes, as their distribution and activity vary substantially across soil depths.

中文翻译：

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温带潮汐盐沼引入英国马齿苋和芦苇增加甲烷排放的机制

摘要 外来植物的引入是广泛的生态威胁，扰乱了全球沿海湿地的碳和养分循环。先前的研究发现，入侵通过增加初级生产和改变产甲烷途径增加了甲烷排放。然而，先前的研究并没有确定变化的深度剖面，而扰动传播到的土壤剖面的深度是需要解决的关键问题之一。在这项研究中，我们说明了 S. anglica 和 P. australis 的引入对潜在甲烷产生、土壤生物地球化学和土壤微生物群落的影响的深度剖面，这些在由于入侵而增加的甲烷排放中起着重要作用。进行了现场实地测量和厌氧培养，以确定深度剖面的机械差异。S. anglica 和 P. australis 的引入都通过不同的微生物机制增加了甲烷排放，具体取决于深度剖面。分别在引入 S. anglica 和 P. australis 的沼泽的浅层和深层土壤中刺激了潜在的甲烷生产。S. anglica 增加了表层土壤中甲基营养甲烷生成的贡献，而 P. australis 降低了所有土壤层中硫酸盐还原剂的竞争性抑制。这些结果强调了地下微生物活动和潮汐沼泽碳循环中垂直分布的重要性。进一步的植物入侵研究应侧重于微生物过程的深度剖面，