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Plant, microbial and ecosystem carbon use efficiencies interact to stabilize microbial growth as a fraction of gross primary production
Author(s) -
Sinsabaugh Robert L.,
Moorhead Daryl L.,
Xu Xiaofeng,
Litvak Marcy E.
Publication year - 2017
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.14485
Subject(s) - ecosystem , primary production , environmental science , biomass (ecology) , soil carbon , carbon sequestration , organic matter , carbon fibers , soil organic matter , terrestrial ecosystem , carbon cycle , soil water , environmental chemistry , ecology , soil science , atmospheric sciences , chemistry , biology , carbon dioxide , mathematics , algorithm , composite number , geology
Summary The carbon use efficiency of plants ( CUE a ) and microorganisms ( CUE h ) determines rates of biomass turnover and soil carbon sequestration. We evaluated the hypothesis that CUE a and CUE h counterbalance at a large scale, stabilizing microbial growth (μ) as a fraction of gross primary production ( GPP ). Collating data from published studies, we correlated annual CUE a , estimated from satellite imagery, with locally determined soil CUE h for 100 globally distributed sites. Ecosystem CUE e , the ratio of net ecosystem production ( NEP ) to GPP , was estimated for each site using published models. At the ecosystem scale, CUE a and CUE h were inversely related. At the global scale, the apparent temperature sensitivity of CUE h with respect to mean annual temperature ( MAT ) was similar for organic and mineral soils (0.029°C −1 ). CUE a and CUE e were inversely related to MAT , with apparent sensitivities of −0.009 and −0.032°C −1 , respectively. These trends constrain the ratio μ : GPP (= (CUE a × CUE h )/(1 − CUE e )) with respect to MAT by counterbalancing the apparent temperature sensitivities of the component processes. At the ecosystem scale, the counterbalance is effected by modulating soil organic matter stocks. The results suggest that a μ : GPP value of c . 0.13 is a homeostatic steady state for ecosystem carbon fluxes at a large scale.