title: Roots and fungi accelerate carbon and nitrogen cycling in forests exposed to elevated CO2.
abstract: A common finding in multiple CO(2) enrichment experiments in forests is the lack of soil carbon (C) accumulation owing to microbial priming of 'old' soil organic matter (SOM). However, soil C losses may also result from the accelerated turnover of 'young' microbial tissues that are rich in nitrogen (N) relative to bulk SOM. We measured root-induced changes in soil C dynamics in a pine forest exposed to elevated CO(2) and N enrichment by combining stable isotope analyses, molecular characterisations of SOM and microbial assays. We find strong evidence that the accelerated turnover of root-derived C under elevated CO(2) is sufficient in magnitude to offset increased belowground inputs. In addition, the C losses were associated with accelerated N cycling, suggesting that trees exposed to elevated CO(2) not only enhance N availability by stimulating microbial decomposition of SOM via priming but also increase the rate at which N cycles through microbial pools.
authors: Department of Biology, 1001 E. Third St, Indiana University, Bloomington, IN 47403, USA. rpp6@indiana.edu
authors: Richard P
authors: RP
authors: Phillips
authors: Ina C
authors: IC
authors: Meier
authors: Emily S
authors: ES
authors: Bernhardt
authors: A Stuart
authors: AS
authors: Grandy
authors: Kyle
authors: K
authors: Wickings
authors: Adrien C
authors: AC
authors: Finzi
mesh_terms: D057486:Carbon Cycle; D002245:Carbon Dioxide; D005658:Fungi; D009584:Nitrogen / Q000378:metabolism*; D028223:Pinus; D018517:Plant Roots / Q000378:metabolism / Q000382:microbiology; D012988:Soil Microbiology; D014197:Trees
chemical_list: D002245:Carbon Dioxide; D009584:Nitrogen