Forest soil carbon oxidation state and oxidative ratio responses to elevated CO2

摘要: The oxidative ratio (OR) of the biosphere is stoichiometric (O2/CO2) gas exchange by photosynthesis and respiration—a key parameter in budgeting calculations land ocean carbon sinks. Carbon cycle-climate feedbacks could alter OR affecting quantity quality organic matter plant biomass soil pools. This study considers effect elevated atmospheric dioxide concentrations ([CO2]) on a hardwood forest after nine growing seasons Free-Air CO2 Enrichment. We measured changes oxidation state (Cox) pools as proxy for ecosystem OR. net primary production, 1.039, was not affected [CO2]. However, Cox pool 40% higher at [CO2], estimated values respiration increased from 1.006 ambient [CO2] to 1.054 A biochemical inventory ascribed increases faster turnover reduced substrates, lignin lipids, implicates heterotrophic community response driver disequilibrium constitutes an unexpected terrestrial O2 sink. budgets constructed under assumption equilibrium would equate such sink uptake ocean. potential climate-driven disequilibriua cycling warrants further investigation.