title: Genetic linkage of soil carbon pools and microbial functions in subtropical freshwater wetlands in response to experimental warming.
abstract: Rising climate temperatures in the future are predicted to accelerate the microbial decomposition of soil organic matter. A field microcosm experiment was carried out to examine the impact of soil warming in freshwater wetlands on different organic carbon (C) pools and associated microbial functional responses. GeoChip 4.0, a functional gene microarray, was used to determine microbial gene diversity and functional potential for C degradation. Experimental warming significantly increased soil pore water dissolved organic C and phosphorus (P) concentrations, leading to a higher potential for C emission and P export. Such losses of total organic C stored in soil could be traced back to the decomposition of recalcitrant organic C. Warming preferentially stimulated genes for degrading recalcitrant C over labile C. This was especially true for genes encoding cellobiase and mnp for cellulose and lignin degradation, respectively. We confirmed this with warming-enhanced polyphenol oxidase and peroxidase activities for recalcitrant C acquisition and greater increases in recalcitrant C use efficiency than in labile C use efficiency (average percentage increases of 48% versus 28%, respectively). The relative abundance of lignin-degrading genes increased by 15% under warming; meanwhile, soil fungi, as the primary decomposers of lignin, were greater in abundance by 27%. This work suggests that future warming may enhance the potential for accelerated fungal decomposition of lignin-like compounds, leading to greater microbially mediated C losses than previously estimated in freshwater wetlands.
authors.affiliation: College of Environmental and Resource Science, Research Center of Water and Watershed Sustainability, Zhejiang University, Hangzhou, China.
authors.forename: Hang
authors.initials: H
authors.lastname: Wang
authors.forename: Zhili
authors.initials: Z
authors.lastname: He
authors.forename: Zhenmei
authors.initials: Z
authors.lastname: Lu
authors.forename: Jizhong
authors.initials: J
authors.lastname: Zhou
authors.forename: Joy D
authors.initials: JD
authors.lastname: Van Nostrand
authors.forename: Xinhua
authors.initials: X
authors.lastname: Xu
authors.forename: Zhijian
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D044822:Biodiversity; D018533:Biomass; D002244:Carbon / Q000737:chemistry / Q000378:metabolism*; D004156:Catechol Oxidase / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism; D002980:Climate; D057231:Climate Change; D017753:Ecosystem; D005618:Fresh Water / Q000382:microbiology*; D005658:Fungi / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D014644:Genetic Variation; D006361:Heating; D008031:Lignin / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism; D010758:Phosphorus / Q000737:chemistry / Q000378:metabolism; D012987:Soil / Q000032:analysis / Q000737:chemistry*; D012988:Soil Microbiology; D013696:Temperature; D053833:Wetlands; D001617:beta-Glucosidase / Q000235:genetics
chemical_list: D012987:Soil; D010758:Phosphorus; D002244:Carbon; D002482:Cellulose; D008031:Lignin; D004156:Catechol Oxidase; D009195:Peroxidase; D001617:beta-Glucosidase