Water tables in high-latitude peatlands are expected to fall because of climate change, with significant consequences for carbon cycling in these ecosystems. At present, the understanding of how climate-induced changes will affect soil microbial communities and functions in peatlands still remains controversial. In this study, we compared the potential activities of soil oxidase and hydrolytic enzymes and microbial communities at different depths in a minerotrophic peatland, part of which had been drained for many years and part of which was natural. The results showed that the microbial communities and enzyme activities differed considerably between the drained peat and the natural peat, and that the degree of change varied by depth in the profile. The soil oxidase activities and hydrolase activities (β-1,4-N-acetylglucosaminidase and acid phosphatase) in the oxic zone (0–10 cm) were higher in the drained peat than in the natural peat, but the β-1,4-glucosidase activities decreased in the oxic zone after drainage. Soil enzyme activities in the anoxic zone were lower in the drained peat than in the natural peat. This suggests that drainage disturbance in this peatland does not support enhanced oxidative enzyme activity as hypothesized by the “enzyme-latch” mechanism. The soil total phospholipid fatty acids (PLFAs) and bacterial, fungal, and actinomycetic PLFAs in the oxic zone were lower in the drained peat than in the natural peat. The total PLFAs and bacterial PLFAs were higher in the transitional zone of the drained peat than the natural peat, but remained similar in the anoxic zone of the drained and natural peat. The fungi/bacteria and gram-positive/gram-negative ratios were lower in the drained peat than in the natural peat. The soil bacterial communities was strongly and positively linked with the β-1,4-glucosidase activities involved in carbon transformation, whereas the fungi was positively associated with oxidase activities driving carbon oxidation. We found that these variations in the microbial communities and enzyme activities were associated with differences in the litter quality, soil organic carbon, soil moisture content, and the pH between the drained peat and natural peat. These observations indicate a modification in microbial communities and their activities reflective of changing peat C cycling. The observed reduction in microbial biomass with peatland drainage appears to have also resulted in reductions in enzyme activity suggesting potential limits to the ‘enzyme-latch’ mechanism for peatland C loss following longer-term drainage.

由于气候变化，高纬度泥炭地的地下水位预计会下降，对这些生态系统中的碳循环产生重大影响。目前，关于气候引起的变化将如何影响泥炭地土壤微生物群落和功能的理解仍然存在争议。在这项研究中，我们比较了矿质营养泥炭地中不同深度的土壤氧化酶和水解酶的潜在活性以及微生物群落，其中一部分已被排水多年，一部分是天然的。结果表明，排水泥炭和天然泥炭的微生物群落和酶活性差异很大，变化程度因剖面深度而异。土壤氧化酶活性和水解酶活性（β-1，排水泥炭中好氧带（0-10 cm）的4-N-乙酰氨基葡萄糖苷酶和酸性磷酸酶高于天然泥炭，但排水后好氧带的β-1,4-葡萄糖苷酶活性降低。排水泥炭中缺氧区的土壤酶活性低于天然泥炭。这表明泥炭地中的排水障碍不支持增强的氧化酶活性，正如“酶闩锁”机制所假设的那样。排水泥炭中土壤总磷脂脂肪酸 (PLFAs) 和细菌、真菌和放线菌 PLFAs 在好氧带中低于天然泥炭。排水泥炭过渡区的总PLFAs和细菌PLFAs高于天然泥炭，但在排水泥炭和天然泥炭的缺氧区保持相似。排水泥炭中的真菌/细菌和革兰氏阳性/革兰氏阴性比率低于天然泥炭。土壤细菌群落与参与碳转化的 β-1,4-葡萄糖苷酶活性呈强正相关，而真菌与驱动碳氧化的氧化酶活性呈正相关。我们发现微生物群落和酶活性的这些变化与凋落物质量、土壤有机碳、土壤水分含量以及排水泥炭和天然泥炭之间的 pH 值差异有关。这些观察结果表明微生物群落及其活动的改变反映了泥炭 C 循环的变化。