TY - JOUR
T1 - Impact of mesophyll diffusion on estimated global land CO2 fertilization
AU - Sun, Ying
AU - Gu, Lianhong
AU - Dickinson, Robert E.
AU - Norby, Richard J.
AU - Pallardy, Stephen G.
AU - Hoffman, Forrest M.
PY - 2014/11/4
Y1 - 2014/11/4
N2 - In C3 plants, CO2 concentrations drop considerably along mesophyll diffusion pathways from substomatal cavities to chloroplasts where CO2 assimilation occurs. Global carbon cycle models have not explicitly represented this internal drawdownand therefore overestimate CO2 available for carboxylation and underestimate photosynthetic responsiveness to atmospheric CO2. An explicit consideration of mesophyll diffusion increases the modeled cumulative CO2 fertilization effect (CFE) for global gross primary production (GPP) from 915 to 1,057 PgC for the period of 1901-2010. This increase represents a 16% correction, which is large enough to explain the persistent overestimation of growth rates of historical atmospheric CO2 by Earth system models. Without this correction, the CFE for global GPP is underestimated by 0.05 PgC/y/ppm. This finding implies that the contemporary terrestrial biosphere is more CO2 limited than previously thought.
AB - In C3 plants, CO2 concentrations drop considerably along mesophyll diffusion pathways from substomatal cavities to chloroplasts where CO2 assimilation occurs. Global carbon cycle models have not explicitly represented this internal drawdownand therefore overestimate CO2 available for carboxylation and underestimate photosynthetic responsiveness to atmospheric CO2. An explicit consideration of mesophyll diffusion increases the modeled cumulative CO2 fertilization effect (CFE) for global gross primary production (GPP) from 915 to 1,057 PgC for the period of 1901-2010. This increase represents a 16% correction, which is large enough to explain the persistent overestimation of growth rates of historical atmospheric CO2 by Earth system models. Without this correction, the CFE for global GPP is underestimated by 0.05 PgC/y/ppm. This finding implies that the contemporary terrestrial biosphere is more CO2 limited than previously thought.
KW - Carbon cycle
KW - Co fertilization
KW - Gross primary production
KW - Mesophyll conductance
KW - Photosynthetic model
UR - http://www.scopus.com/inward/record.url?scp=84914689917&partnerID=8YFLogxK
U2 - 10.1073/pnas.1418075111
DO - 10.1073/pnas.1418075111
M3 - Article
C2 - 25313079
AN - SCOPUS:84914689917
SN - 0027-8424
VL - 111
SP - 15774
EP - 15779
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 44
ER -