Stimulation of soil respiration by elevated CO2 is enhanced under nitrogen limitation in a decade-long grassland study.
Proc Natl Acad Sci U S A
; 117(52): 33317-33324, 2020 12 29.
Article
en En
| MEDLINE
| ID: mdl-33318221
ABSTRACT
Whether and how CO2 and nitrogen (N) availability interact to influence carbon (C) cycling processes such as soil respiration remains a question of considerable uncertainty in projecting future C-climate feedbacks, which are strongly influenced by multiple global change drivers, including elevated atmospheric CO2 concentrations (eCO2) and increased N deposition. However, because decades of research on the responses of ecosystems to eCO2 and N enrichment have been done largely independently, their interactive effects on soil respiratory CO2 efflux remain unresolved. Here, we show that in a multifactor free-air CO2 enrichment experiment, BioCON (Biodiversity, CO2, and N deposition) in Minnesota, the positive response of soil respiration to eCO2 gradually strengthened at ambient (low) N supply but not enriched (high) N supply for the 12-y experimental period from 1998 to 2009. In contrast to earlier years, eCO2 stimulated soil respiration twice as much at low than at high N supply from 2006 to 2009. In parallel, microbial C degradation genes were significantly boosted by eCO2 at low but not high N supply. Incorporating those functional genes into a coupled C-N ecosystem model reduced model parameter uncertainty and improved the projections of the effects of different CO2 and N levels on soil respiration. If our observed results generalize to other ecosystems, they imply widely positive effects of eCO2 on soil respiration even in infertile systems.
Palabras clave
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Suelo
/
Dióxido de Carbono
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Pradera
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Nitrógeno
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Año:
2020
Tipo del documento:
Article
País de afiliación:
China