森林演替过程中土壤有机质动态的微生物学控制机制研究

Soil microorganisms regulate fundamental biochemical processes in litter mineralization and organic matter formation and are thus, important drivers for soil organic matter cycles with potential consequences for overall ecosystem process and functioning. Much research has focused on global change impacts on plant diversity and nutrient cycling, but somewhat less attention has been given to the role of microbial communities in mediating biogeochemical and ecological processes, particularly regarding linking microbial community structure with functions and understanding their response/feedback to ecosystem development, which nevertheless is important for sustaining ecosystem productivity and for predicting the impacts of future disturbances. Here, we propose to investigate how microbial community respond to changes in vegetation covers and further how those induced responses impact the magnitude, composition and allocation (source configuration) of soil organic carbon pool through microbial catabolism and anabolism in the context of temperate forest succession in Changbai Mountain Research Station. We will combine biomarker assays, modern genomic and chemical technology, and soil fractionation method to identify relationships between soil microbial community, plant litter chemistry, and soil organic matter dynamics during forest succession. We characterized microbial community composition and functional group using phospholipids fatty acids analysis (PLFA) and DNA sequencing technique (Illumina), soil and litter carbon chemistry using pyrolysis-GC/MS, and source configuration of soil carbon pool using stable biomarkers such as lignin and amino sugar. Through linear regression model with multivariate ordination analysis, we will address 1) what effects of temperate forest succession has on soil microbial biomass, diversity and activity; 2) which key factors explain microbial community dynamics with vegetation cover change; 3) how microbial community link to function in soil organic matter cycling and storage during forest succession. We aim to a better understand the important, but largely unknown links between aboveground and belowground dynamics.

微生物作为土壤有机质循环转化的重要驱动者，直接参与凋落物矿化和有机质形成过程，能够对生态系统过程与功能产生重要影响。了解微生物群落对生态系统发育过程的响应和反馈机制，对生态系统生产力的可持续发展和未来环境扰动的预测具有重要意义。以长白山森林演替序列为研究对象，探讨温带森林演替过程中地下微生物群落如何响应地上植被变化及其如何通过微生物异化和同化代谢过程来控制土壤碳库的容量、组成和分配。采用生物标识物、现代基因组学和化学检测及土壤物理分级等方法，明确森林演替序列下土壤微生物群落、植物凋落物化学组成及土壤有机质动态三者的互作关系，拟阐明在森林演替过程中：1）土壤微生物群落的响应机制；2）影响微生物群落性质的主控因素；3）微生物群落代谢模式在土壤有机碳转化和固存过程中的作用及相关的主要功能群和优势种。本研究可为探索重要且未明确的生态系统地上-地下生态过程之间的动态关联提供理论支持。

微生物作为土壤有机质循环转化的重要驱动者，直接参与有机质形成过程，能够对生态系统过程与功能产生重要影响。了解微生物群落对生态系统发育过程的响应和反馈机制，对生态系统生产力的可持续发展和未来环境扰动的预测具有重要意义。以长白山森林演替序列为研究对象，探讨温带森林演替过程中地下微生物群落如何响应地上植被变化及其如何通过微生物异化和同化代谢过程来调控土壤碳库的容量。采用生物标识物、高通量测序技术和化学检测等方法，明确森林演替序列下土壤微生物群落及土壤有机质动态两者之间关系，拟阐明在森林演替过程中：1）土壤微生物群落的响应机制；2）影响微生物群落性质的主控因素；3）微生物群落代谢模式在土壤有机碳转化和固存过程中的作用。我们的研究发现森林演替过程中土壤原核生物群落的多样性、组成以及门类群的相对丰度发生较大变化；另外，土壤有机质的数量和质量是驱动细菌群落构建的主要因素。土壤微生物通过活性微生物群落（异化代谢）和微生物死亡残体（同化代谢）调控并贡献了森林演替过程中土壤有机碳的积累。本研究可为探索微生物与土壤有机质之间的动态关联提供理论支持；结合全球气候变化背景，森林恢复促进了土壤有机碳积累，可以作为有效的森林管理措施减缓全球气候变暖。