Elevated atmospheric CO2 increases microbial growth rates in soil: results of three CO2 enrichment experiments

• DOI: 10.1111/j.1365-2486.2009.02006.x
• Publication Date: 2009-06-22T17:19:25Z
• Authors: EVGENIA BLAGODATS...; SERGEY BLAGODATSKY; MAXIM DORODNIKOV; YAKOV KUZYAKOV
• Keywords: Mesocosm; Soil respiration; Bulk soil

Abstract Increasing the belowground translocation of assimilated carbon by plants grown under elevated CO 2 can cause a shift in structure and activity microbial community responsible for turnover organic matter soil. We investigated long‐term effect atmosphere on biomass specific growth rates root‐free rhizosphere The experiments were conducted two free air dioxide enrichment (FACE) systems: Hohenheim Braunschweig, as well intensively managed forest mesocosm Biosphere Laboratory (B2L) Oracle, AZ. Specific ( μ ) determined using substrate‐induced respiration response after glucose and/or yeast extract addition to For B2L both FACE systems, up 58% higher observed vs. ambient , depending site, plant species N fertilization. μ‐ values increased linearly with atmospheric concentration at all three sites. microorganisms was dependent for: Brassica napus = Triticum aestivum < Beta vulgaris Populus deltoides . deficiency affected directly (N limitation) indirectly (changing quantity fine roots). So, 50% decrease fertilization caused overall increase or species. value lower growing then those glucose, i.e. smoothed rich simple substrate. r/K strategies ratio be better revealed studying (glucose) than substrate mixtures (yeast extract). Our results clearly showed that functional characteristics soil (i.e. rates) rather total amount are sensitive conclude more abundant available organics released roots altered ecological strategy specifically contribution fast‐growing r‐selected observed. These changes may counterbalance C input into concentration.