Department of Microbiology, 00014 University of Helsinki, Helsinki, Finland.
Helsinki Institute of Sustainability Science (HELSUS), 00014 University of Helsinki, Helsinki, Finland.
FEMS Microbiol Ecol. 2022 Aug 1;98(8). doi: 10.1093/femsec/fiac079.
Due to climate change, increased microbial activity in high-latitude soils may lead to higher greenhouse gas (GHG) emissions. However, microbial GHG production and consumption mechanisms in tundra soils are not thoroughly understood. To investigate how the diversity and functional potential of bacterial and archaeal communities vary across vegetation types and soil layers, we analyzed 116 soil metatranscriptomes from 73 sites in the Finnish sub-Arctic. Meadow soils were characterized by higher pH and lower soil organic matter (SOM) and carbon/nitrogen ratio. By contrast, dwarf shrub-dominated ecosystems had higher SOM and lower pH. Although Actinobacteria, Acidobacteria, Alphaproteobacteria and Planctomycetes were dominant in all communities, there were significant differences at the genus level between vegetation types; plant polymer-degrading groups were more active in shrub-dominated soils than in meadows. Given that climate-change scenarios predict the expansion of shrubs at high latitudes, our results indicate that tundra soil microbial communities harbor potential decomposers of increased plant litter, which may affect the rate of carbon turnover in tundra soils. Additionally, transcripts of methanotrophs were detected in the mineral layer of all soils, which may moderate methane fluxes. This study provides new insights into possible shifts in tundra microbial diversity and activity due to climate change.
由于气候变化，高纬度土壤中微生物活动的增加可能导致温室气体（GHG）排放增加。然而，苔原土壤中微生物 GHG 产生和消耗的机制还没有被彻底理解。为了研究细菌和古菌群落的多样性和功能潜力如何随植被类型和土壤层变化，我们分析了来自芬兰北极地区 73 个地点的 116 个土壤宏转录组。草地土壤的特点是 pH 值较高，土壤有机质（SOM）和碳/氮比较低。相比之下，矮灌木主导的生态系统具有较高的 SOM 和较低的 pH 值。尽管放线菌、酸杆菌、α变形菌和浮霉菌在所有群落中都是优势菌，但植被类型之间在属水平上存在显著差异；在灌木主导的土壤中，植物聚合物降解菌比在草地中更为活跃。鉴于气候变化情景预测高纬度地区灌木的扩张，我们的研究结果表明，苔原土壤微生物群落蕴藏着潜在的增加植物凋落物的分解者，这可能会影响苔原土壤中碳的转化速率。此外，所有土壤的矿物质层中都检测到了甲烷氧化菌的转录本，这可能会调节甲烷通量。这项研究为气候变化导致的苔原微生物多样性和活性的可能变化提供了新的见解。
