PS 69-153 - Response of ecosystem nitrogen cycle to elevated CO2: A meta-analysis

Thursday, August 11, 2011
Exhibit Hall 3, Austin Convention Center
Xuan Qi, Botany, University of Oklahoma, Norman, OK, Yiqi Luo, Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK and Xuhui Zhou, Institute of Biodiversity, Fudan University, Shanghai, China
Background/Question/Methods

Carbon (C) sequestration in terrestrial ecosystems largely depends on nitrogen (N) availability in response to rising atmospheric CO2, which would result in progressive N limitation (PNL) that C and N are simultaneously fixed in long-lived plant biomass and soil organic matter. Hence, it is critical to examine how N processes respond to elevated CO2 to alleviate PNL.  Here we evaluated the central tendencies of the responses of several variables associated with ecosystem N cycle to elevated CO2, using data extracted from peer-reviewed papers. 

Results/Conclusions

Our results showed that elevated CO2 induced uptake of inorganic N, hence reduce inorganic nitrogen leaching by around 20% under elevated CO2. N addition may trigger this effect, which results in a 40% reduction under elevated CO2 compared with ambient CO2. However, only N addition increased inorganic nitrogen leaching by 150%.  Elevated CO2 also affected N mineralization, N2O flux, nitrification, and denitrification.  Our results indicate that elevated CO2 may alleviate PNL through reduce leaching pathway.

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