HAL : ird-00392102, version 1

Code IRD Horizon : fdi:010046216

Fiche détaillée

Récupérer au format BibTeX - EndNote - TEI - RefWorks -

Biogeosciences Discussions 5 (2008) 4071-4105

Precipitation as driver of carbon fluxes in 11 African ecosystems

L. Merbold (  Auteur correspondant ) 1, J. Ardo 2, A. Arneth 3, R.J. Scholes 4, Yann Nouvellon 5, A. De Grandcourt 6, S. Archibald 7, J. M. Bonnefond 8, Nicolas Boulain 9, C. Bruemmer 10, N. Brueggemann 10, B. Cappelaere 9, Eric Ceschia 11, H.A.M. El Khidir 12, B.A. El Tahir 12, U. Falk 13, J. Lloyd 14, L. Kergoat 11, V. Le Dantec 11, E. Mougin 11, M. Muchinda 15, M.M. Mukelabai 15, D. Ramier 9, Olivier Roupsard 6, F. Timouk 11, E.M. Veenendaal 16, W. L. Kutsch 1

(2008)

This study reports carbon and water fluxes between the land surface and atmosphere in eleven different ecosystems types in Sub-Saharan Africa, as measured using eddy covariance (EC) technology in the first two years of the CarboAfrica network operation. The ecosystems for which data were available ranged in mean annual rainfall from 320mm (Sudan) to 1150mm (The Republic of Congo) and include a spectrum of vegetation types (or land cover) (open savannas, woodlands, croplands and grasslands). Given the shortness of the record, the EC data were analysed across the network rather than longitudinally at sites, in order to understand the driving factors for ecosystem respiration and carbon assimilation, and to reveal the different water use strategies in these highly seasonal environments. Values for maximum net carbon assimilation rates (photosynthesis) ranged from 12 μmolCO2 m−2 s−1 in a dry, open Acacia savanna (C3-plants) up to 40 μmolCO2 m−2 s−1 for a tropical moist grassland. Maximum carbon assimilation rates were highly correlated with mean annual rainfall (R2=0.89). Maximum photosynthetic uptake rates were positively related to satellite-derived fAPAR. Ecosystem respiration was dependent on temperature at all sites, and was additionally dependent on soil water content at sites receiving less than 1000mm of rain per year. All included ecosystems, except the Congolese grassland, showed a strong decrease in 30-min assimilation rates with increasing water vapour pressure deficit above 2.0 kPa.

1 :	MPI
	MPI
2 :	Department of Physical Geography and Ecosystems Analysis
	Department
3 :	Department of Physical Geography and Ecosystems Analysis
	Geobiosphere Science Centre
4 :	Natural Resources and the Environment (CSIR)
	CSIR
5 :	UPR Ecosystèmes des plantations
	Centre de coopération internationale en recherche agronomique pour le développement [CIRAD] : UPR80
6 :	Fonctionnement et pilotage des écosystèmes de plantations (Ecosystèmes de plantations)
	Centre de coopération internationale en recherche agronomique pour le développement [CIRAD] : UPR80
7 :	Natural Resources and the Environment (CSIR)
	scir
8 :	EPHYSE
	Institut national de la recherche agronomique (INRA)
9 :	Hydrosciences Montpellier (HSM)
	CNRS : UMR5569 – Institut de recherche pour le développement [IRD] – Université Montpellier II - Sciences et techniques
10 :	Atmospheric Chemistry Department
	Max-Planck-Institute for Chemistry (MPI-CH)
11 :	Centre d'études spatiales de la biosphère (CESBIO)
	CNRS : UMR5126 – Institut de recherche pour le développement [IRD] – CNES – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier [UPS] - Toulouse III
12 :	Agricultural Research Cooperation
	Agricultural Research Cooperation
13 :	Department of Ecology and Resource Management
	Department of Ecology
14 :	Earth and Biosphere Institute
	School of Geography
15 :	Zambia Meteorological Department
	Department Meteorological
16 :	Nature Conservation and Plant Ecology Group
	Nature Conservation

domaine

:

Sciences du Vivant/Ecologie, Environnement/Ecosystèmes

ird-00392102, version 1

http://hal.ird.fr/ird-00392102

oai:hal.ird.fr:ird-00392102

Contributeur : Dominique Bruel <>

Soumis le : Vendredi 5 Juin 2009, 15:05:44

Dernière modification le : Mardi 11 Août 2009, 18:15:43