东部平原矿区复垦对土壤微生物固碳潜力的影响

Impact of land reclamation on the carbon sequestration potential of soil microorganisms in the disturbed mining area of eastern plain

东部平原矿区复垦土壤受高潜水影响易返碱、肥力低,固碳菌群可有效提升土壤养分。但复垦如何调控微生物固碳能力及影响机制尚不清晰。为此,选取山东邹城东滩矿8,14,17 a复垦年限和对照样为研究对象,利用功能基因芯片和高通量测序技术探究6个固碳相关菌门和12种固碳基因的变化。结果表明:①复垦土壤pH值、溶解性有机碳、土壤β-葡萄糖苷酶和过氧化氢酶活性等均显著高于对照土壤(P<0.01)。复垦17 a后土壤有机碳、微生物量碳、多酚氧化酶活性显著高于对照样,复垦时间效应极显著(P<0.001);②12种固碳基因信号强度随复垦时长不断增大,复垦17 a后已高于或持平对照样,主要分布于酸杆菌门(Acidobacteria)、放线菌门(Actinobacteria)、拟杆菌门(Bacteroidetes)、蓝细菌门(Cyanobacteria)、厚壁菌门(Firmicutes)和变形菌门(Proteobacteria);③固碳菌群丰度与pH、溶解性有机碳、β-葡萄糖苷酶、多酚氧化酶、过氧化氢酶活性之间呈显著相关(P<0.05),多数固碳基因信号强度与pH、微生物量碳、溶解性有机碳及过氧化氢酶活性等环境因子之间也存在一定的相关性。长时间复垦活动影响富集和稀有固碳菌群组成及其功能基因丰度,可通过调控土壤pH、微生物量碳或多酚氧化酶酶活等相关环境因子,提升复垦土壤固碳增汇能力。

In the eastern plain,the reclaimed soil has been affected by the high underground water level in the mining area,and then the soil always presents to be alkaline and barren.As it is well known that the carbon-fixing bacteria could effectively improve soil nutrients,so they might be useful for the poor reclaimed soil.However,it is still not very clear that how reclamation regulates the carbon fixation capacity of microorganisms and its mechanism.In this study,the eight,fourteen and seventeen-years reclamation samples from the Dongtan Mine in Zoucheng,Shandong,China,were selected as the research objects,as well as the control samples.The variation of six carbon-fixation related bacteria phyla,and twelve carbon fixation genes were explored through Geochip and high-throughput sequencing technology.The results show that:①The values of soil pH,dissolved organic carbon,soilβ-glucosidase and catalase activities of the reclaimed soil are significantly higher than those of control soil samples(P<0.01).The soil organic carbon,microbial biomass carbon content,and polyphenol oxidase activity are significantly higher in the 17 years reclaimed soil,when compared to the control samples.The effect of reclamation time on soil properties presented is extremely significant(P<0.001);②The signal intensity of 12 carbon-fixing genes have been increased with the increasing reclamation years.For the 17-years reclamation samples,the data have been higher than or equal to the control.The 12 carbon-fixing genes are mainly distributed in phyla of Acidobacteria,Actinobacteria,Bacteroidetes,Cyanobacteria,Firmicutes and Proteobacteria;and③the abundances of carbon-fixing bacteria are significantly correlated with soil pH,dissolved organic carbon,β-glucosidase,polyphenol oxidase,and catalase activities(P<0.05).There is also a certain correlation between the signal intensity of most carbon fixation genes and the environmental factors,such as soil pH,microbial biomass carbon,dissolved organic carbon and catalase activity.Reclamation activities could affect the composition of abundant and rare carbon-fixing bacteria,as well as the abundance of functional genes.There might be an effective way to enhance the carbon-fixing ability of reclaimed soils and carbon sinks,through regulating the related environmental factors,for example,soil pH value,microbial biomass carbon or polyphenol oxidase enzyme activity,and so on.