Globally, large-scale land drainage has severely deteriorated the functioning and services of peatlands, making restoration plans of the utmost importance. Rewetting is essential for the restoration of drained peatlands, but the level of success including greenhouse gas (GHG) mitigation largely depends on the soil microbiome interactions under the prevailing biogeochemical conditions. Here, we investigated the effects of inundation of drained iron (Fe) -rich peat topsoils on nutrient release, surface water quality, GHG production and consumption, and on the composition and activity of the microbial community. The effect of the addition of different potential electron acceptors on methane (CH₄) production and consumption were studied in incubation experiments. In response to inundation, porewater concentrations of Fe, total inorganic carbon, ammonium, and phosphorus increased. CH₄ emissions increased in the control (i.e. without any additions) and Fe(III) oxide amended incubations upon inundation. This could be explained by the increase in the relative abundance of methanogens even though Fe(III) was previously hypothesized to lower methanogenic activity. In contrast, nitrite, nitrate, and sulfate-rich incubations inhibited methanogenesis. The prolonged exposure to nitrogen oxides stimulated denitrification with nitrous oxide (N₂O) as the main gaseous product, together with an increase in the relative abundance of denitrifying microorganisms. Our results demonstrate that insights into the changes in microbial communities in relation to soil geochemistry explain differences in responses observed in different peat soils observed upon inundation. The increase in emissions of the potent GHGs CH₄ and N₂O from Fe-rich peat topsoils are a major adverse effect in the early stage of inundation.

在全球范围内，大规模的土地排水严重恶化了泥炭地的功能和服务，因此，恢复计划至关重要。重新湿润对于恢复流失的泥炭地至关重要，但是成功的水平包括缓解温室气体（GHG）很大程度上取决于当前生物地球化学条件下土壤微生物组的相互作用。在这里，我们调查了富集排水铁（Fe）的泥炭表土对养分释放，地表水质量，GHG产生和消耗以及微生物群落组成和活性的影响。添加不同的潜在电子受体对甲烷（CH ₄在孵化实验中研究了产量和消耗量。响应淹没，孔隙水中的铁，总无机碳，铵和磷浓度增加。对照（即不加任何添加剂）中CH _4的排放量增加，淹没后修改了Fe（III）的温育条件。这可以用产甲烷菌相对丰度的增加来解释，即使先前假设Fe（III）会降低产甲烷活性。相反，富含亚硝酸盐，硝酸盐和硫酸盐的培养物抑制了甲烷生成。长时间暴露于氮氧化物会激发一氧化二氮（N ₂O）作为主要气体产物，同时反硝化微生物的相对丰度增加。我们的结果表明，与土壤地球化学有关的微生物群落变化的见解解释了在淹没后观察到的不同泥炭土壤中观察到的响应差异。富铁泥炭表层土壤中有效温室气体CH ₄和N ₂ O的排放增加是淹没初期的主要不利影响。