Reference : Elevated atmospheric CO2 in open top chambers increases net nitrification and potenti...
Scientific journals : Article
Life sciences : Phytobiology (plant sciences, forestry, mycology...)
Life sciences : Environmental sciences & ecology
Elevated atmospheric CO2 in open top chambers increases net nitrification and potential denitrification
Carnol, Monique mailto [Université de Liège - ULg > Département des sciences et gestion de l'environnement > Ecologie végétale et microbienne >]
Hogenboom, L. [Université de Liège - ULg > Sciences et gestions de L'Environnement > Ecologie végétale et microbienne > >]
Jach, M. E. [Universiteit Antwerpen - UA > Department of Biology > > >]
Remacle, Jean mailto [Université de Liège - ULg > Sciences et gestion de l'Environnement > Ecologie végétale et microbienne > >]
Ceulemans, R. [Universiteit Antwerpen - UA > Department of Biology > > >]
Global Change Biology
Blackwell Publishing Ltd
Yes (verified by ORBi)
[en] elevated CO2 ; global change ; nitrification ; open top chambers ; potential denitrification
[en] The control of soil nitrogen (N) availability under elevated atmospheric CO2 is central to predicting changes in ecosystem carbon (C) storage and primary productivity. The effects of elevated CO2 on belowground processes have so far attracted limited research and they are assumed to be controlled by indirect effects through changes in plant physiology and chemistry. In this study, we investigated the effects of a 4-year exposure to elevated CO2 (ambient + 400 mumol mol(-1) ) in open top chambers under Scots pine (Pinus sylvestris L) seedlings on soil microbial processes of nitrification and denitrification. Potential denitrification (DP) and potential N-2 O emissions were significantly higher in soils from the elevated CO2 treatment, probably regulated indirectly by the changes in soil conditions (increased pH, C availability and NO3 (-) production). Net N mineralization was mainly accounted for by nitrate production. Nitrate production was significantly larger for soil from the elevated CO2 treatment in the field when incubated in the laboratory under elevated CO2 (increase of 100%), but there was no effect when incubated under ambient CO2 . Net nitrate production of the soil originating from the ambient CO2 treatment in the field was not influenced by laboratory incubation conditions. These results indicate that a direct effect of elevated atmospheric CO2 on soil microbial processes might take place. We hypothesize that physiological adaptation or selection of nitrifiers could occur under elevated CO2 through higher soil CO2 concentrations. Alternatively, lower microbial NH4 assimilation under elevated CO2 might explain the higher net nitrification. We conclude that elevated atmospheric CO2 has a major direct effect on the soil microbial processes of nitrification and denitrification despite generally higher soil CO2 concentrations compared to atmospheric concentrations.
Services Fédéraux des Affaires Scientifiques, Techniques et Culturelles - SSTC ; Université de Liège ; Fonds de la Recherche Scientifique (Communauté française de Belgique) - F.R.S.-FNRS
Researchers ; Professionals ; Students

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