高潜水位矿区复垦土壤微生物演替规律及作用机制研究

The soil problems caused by coal mining have been becoming increasingly prominent, and it has already been the research hotspot of mine environmental ecology. Due to the protection of cultivated land and food security, the ecological restoration of mining area with high groundwater level mainly focused on land reclamation. However, the physical and chemical properties of reclaimed soil and microbial community characteristics have been seriously disturbed, and the quality of reclaimed land is always poor. In this study, applying the technology of high-throughput sequencing and GeoChip, the temporal and spatial succession patterns of the reclaimed soil microbial communities are investigated on the microbial species and functional levels. Combining with massive data, the methods of molecular ecological network construction and statistical analysis of bioinformatics are introduced to explore the control factors affecting the distribution of microbial communities in mining reclaimed soils with high groundwater level, and to solve the scientific problem of how the control factors are related to the succession pattern of soil microbial communities. Furthermore, we are trying to explain the relationship between soil microbial composition and structural function of reclaimed soil, and explore some microbial groups which could respond to and adapt to environmental changes. Furthermore, the affecting mechanism of microbial community will be brought to light in detail. All the studies might provide the technical support and microbial resources for improving the quality of land reclamation.

煤炭开采引起的土壤问题日益突出，已成为矿山环境生态学的研究热点。因耕地保护、粮食安全等原因，高潜水位矿区生态修复以土地复垦为主，但复垦土壤理化性状及微生物群落特征均受严重扰动，复垦土地质量往往较差。本研究以高潜水位矿区塌陷复垦土壤为研究对象，采用高通量测序及基因功能芯片技术，综合物种水平和基因功能水平，探明复垦土壤微生物群落的时空演替规律。进一步引入分子生态网络构建和生物信息学统计分析，结合海量数据，探索影响高潜水位矿区复垦土壤微生物群落分布的控制因子，解决控制因子与土壤微生物群落分布格局有何关联这个科学问题。进而阐述复垦土壤微生物组成和结构功能的关系，探寻能反应和适应环境变化的微生物类群，在此基础上揭示微生物群落的作用机制，为提升矿山土地复垦质量提供技术支撑和微生物资源。

东部平原矿区复垦土壤受高潜水影响易返碱、肥力低，复垦对恢复矿区土壤生产力极为重要，但复垦土壤生产力重建的微生物学机制尚不清晰，其中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复垦8 a、复垦11 a、复垦14 a和复垦17 a 这4个复垦时长和1个未复垦对照土样为研究对象，进行高通量测序和功能基因芯片分析，解析微生物群落组成、潜在功能、组装机制及固碳基因的变化。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）；②群落丰富度随复垦时间增加而增加，且高于对照样。但群落多样性和均匀度却随复垦时间增加而降低（P<0.05）；复垦土壤中酸杆菌门、绿弯菌门、变形菌门和拟杆菌门占主导地位，且前两者相对丰度显著高于对照样（P<0.05），后两者则相反（P<0.05）；③12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、放线菌门、拟杆菌门、蓝细菌门、厚壁菌门和变形菌门；④复垦土壤中辅酶转运与代谢、翻译、核糖体结构与生物发生等8种功能呈正向演替，随复垦时长不断增强，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；⑤平原矿区微生物群落生态网络模块性良好，且关键类群多属酸杆菌门和拟杆菌门。群落组装以确定性过程为主导，同质性选择贡献最大，主要受当地特殊环境操控。且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。这些发现为改善复垦土壤生产力和生态服务提供了理论依据。