title: Relating microbial community structure to functioning in forest soil organic carbon transformation and turnover.
abstract: Forest soils store vast amounts of terrestrial carbon, but we are still limited in mechanistic understanding on how soil organic carbon (SOC) stabilization or turnover is controlled by biotic and abiotic factors in forest ecosystems. We used phospholipid fatty acids (PLFAs) as biomarker to study soil microbial community structure and measured activities of five extracellular enzymes involved in the degradation of cellulose (i.e., β-1,4-glucosidase and cellobiohydrolase), chitin (i.e., β-1,4-N-acetylglucosaminidase), and lignin (i.e., phenol oxidase and peroxidase) as indicators of soil microbial functioning in carbon transformation or turnover across varying biotic and abiotic conditions in a typical temperate forest ecosystem in central China. Redundancy analysis (RDA) was performed to determine the interrelationship between individual PFLAs and biotic and abiotic site factors as well as the linkage between soil microbial structure and function. Path analysis was further conducted to examine the controls of site factors on soil microbial community structure and the regulatory pathway of changes in SOC relating to microbial community structure and function. We found that soil microbial community structure is strongly influenced by water, temperature, SOC, fine root mass, clay content, and C/N ratio in soils and that the relative abundance of Gram-negative bacteria, saprophytic fungi, and actinomycetes explained most of the variations in the specific activities of soil enzymes involved in SOC transformation or turnover. The abundance of soil bacterial communities is strongly linked with the extracellular enzymes involved in carbon transformation, whereas the abundance of saprophytic fungi is associated with activities of extracellular enzymes driving carbon oxidation. Findings in this study demonstrate the complex interactions and linkage among plant traits, microenvironment, and soil physiochemical properties in affecting SOC via microbial regulations.
authors.affiliation: Ministry of Education Key Laboratory for Silviculture and Conservation, College of Forest Science, Beijing Forestry University Beijing, 100083, China ; Institute of Forestry and Climate Change Research, Beijing Forestry University Beijing, 100083, China.
authors.forename: Yeming
authors.initials: Y
authors.lastname: You
authors.affiliation: Ministry of Education Key Laboratory for Silviculture and Conservation, College of Forest Science, Beijing Forestry University Beijing, 100083, China ; Institute of Forestry and Climate Change Research, Beijing Forestry University Beijing, 100083, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Forestry Administration of China Key Laboratory of Forest Ecology and Environment, Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry Beijing, 100091, China.
authors.forename: Xueman
authors.initials: X
authors.lastname: Huang
authors.affiliation: Ministry of Education Key Laboratory for Silviculture and Conservation, College of Forest Science, Beijing Forestry University Beijing, 100083, China ; Institute of Forestry and Climate Change Research, Beijing Forestry University Beijing, 100083, China.
authors.forename: Zuoxin
authors.initials: Z
authors.lastname: Tang
authors.affiliation: State Forestry Administration of China Key Laboratory of Forest Ecology and Environment, Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry Beijing, 100091, China.
authors.forename: Shirong
authors.initials: S
authors.lastname: Liu
authors.affiliation: Ministry of Education Key Laboratory for Silviculture and Conservation, College of Forest Science, Beijing Forestry University Beijing, 100083, China ; Institute of Forestry and Climate Change Research, Beijing Forestry University Beijing, 100083, China.
authors.forename: Osbert J
authors.initials: OJ
authors.lastname: Sun
keywords: Decomposition; extracellular enzymes; forest soil carbon; pathway analysis; phospholipid fatty acids (PLFAs); redundancy analysis (RDA); temperate forest