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Comparison of nitrogen monoxide emissions from several African tropical ecosystems and influence of season and fire
Serça D., Delmas R., Le Roux X., Parsons D., Scholes M., Abbadie L., Lensi R., Ronce O., Labroue L.
Global Biogeochemical Cycles 12, 4 (1998) 637-651 - http://hal-sde.archives-ouvertes.fr/halsde-00352350
Articles dans des revues avec comité de lecture
Sciences de l'environnement/Milieux et Changements globaux/Ecosystèmes
Comparison of nitrogen monoxide emissions from several African tropical ecosystems and influence of season and fire
Dominique Serça ( ) 1, Robert Delmas () 1, X. Le Roux, Dab Parsons, M. Scholes 2, L. Abbadie, R. Lensi () 3, Ophélie Ronce () 4, L. Labroue
1 :  Laboratoire d'aérologie (LA)
http://www.aero.obs-mip.fr/
CNRS : UMR5560 – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier (UPS) - Toulouse III
14 avenue Edouard Belin 31400 Toulouse
France
2 :  Department of Animal, Plant and Environmental Sciences (CSIR)
University of the Witwaterstrand
Johannesburg, 2000
Afrique Du Sud
3 :  Ecologie microbienne (EM)
http://ecomicro.univ-lyon1.fr
CNRS : UMR5557 – Institut national de la recherche agronomique (INRA) : UR1193 – Université Claude Bernard - Lyon I – Ecole Nationale Vétérinaire de Lyon
BAT GREGOR MENDEL (ex 741)-4 et 43 Bvd du 11 Novembre 1918 69622 VILLEURBANNE CEDEX
France
4 :  Institut des Sciences de l'Evolution - Montpellier (ISEM)
http://www.isem.univ-montp2.fr/
CNRS : UMR5554 – Université Montpellier II - Sciences et techniques – Institut de recherche pour le développement [IRD] : UMR226
Place E. Bataillon CC 064 34095 Montpellier Cedex 05
France
Équipe Troposphère
NO emission rates from soils were measured for twelve major African ecosystems in four countries (Congo, Niger, Ivory Coast, and South Africa) and within four major phytogeographic domains: the Guineo-Congolese, Guinean, Sahelian, and Zambezian domains. Measurements were performed during wet and/or dry seasons. All the measurements were made with the same dynamic chamber device, which allowed true comparisons to be made. This study showed that emission rates strongly differed between ecosystems and exhibited a marked temporal variability. Ecosystem effect was highly significant during both the dry and wet seasons. Emission rates were low (<0.6 ng NO-N m(-2) s(-1)) in Hyparrhenia and Loudetia savannas of the Guinean or Guineo-Congolese domains. Intermediate NO fluxes were obtained in rain forest and gallery forest ecosystems, in a broad-leafed savanna and in a seasonally wetted grassland (sandy soil) of the Zambezian domain, and in a dry fallow savanna of the Sahelian domain. Emission rates were maximum (>7 ng NO-N m(-2) s(-1)) in a seasonally wetted grassland (site 2) and in particular sites subjected to various disturbances, for example soil fauna activity (termite mounds) or past human disturbance (Acacia patches-settlement site). Microbial activity potentials (i.e., carbon mineralization, nitrification, denitrification, and total net N mineralization) were determined for most of the soils where NO fluxes were measured. In some sites, these potential activities were useful to identify the major processes controlling NO emission rates. Denitrification potential was very low and could not explain substantial NO fluxes from broad-and fine-leafed savannas and Hyperthelia savannas of the Zambezian domain. Very low potentials of both nitrification and denitrification could be related to the low NO fluxes for the three Guinean savanna sites studied. NO fluxes were significantly higher during the wet season than the dry season in both savanna and forest ecosystems. Emission rates in savanna ecosystems were significantly increased within a few hours after fire. The measurements presented here provide a unique, consistent database which can be used to further analyze the processes involved in the spatial and temporal variations of NO emissions.
Anglais

Global Biogeochemical Cycles
Publisher American Geophysical Union (AGU)
ISSN 0886-6236 
internationale
12/1998
12
4
637-651

MID-PACIFIC TROPOSPHERE – NITRIC-OXIDE EMISSIONS – BIOGENIC EMISSIONS – FIELD-MEASUREMENTS – SAVANNA SOILS – SOUTH-AFRICA – GLOBAL INVENTORY – NOX EMISSIONS – COSTA-RICA – FOREST