Precipitation as driver of carbon fluxes in 11 African ecosystems

Merbold L., Ardö Junas, Arneth Almur, Scholes Robert J., Nouvellon Yann, De Grandcourt Agnès, Archibald S., Bonnefond Jean-Marc, Boulain N., Brueggemann N., Bruemmer C., Cappelaere Bernard, Ceschia Eric, El-Khidir H.A.M., El-Tahir B.A., Falk U., Lloyd Jon, Kergoat Laurent, Le Dantec Valérie, Mougin Eric, Muchinda M., Mukelabai M.M., Ramier D., Roupsard Olivier, Timouk F., Veenendaal Elmar M., Kutsch Werner L.. 2009. Precipitation as driver of carbon fluxes in 11 African ecosystems. Biogeosciences, 6 (6) : 1027-1041.

Quartile : Q1, Sujet : GEOSCIENCES, MULTIDISCIPLINARY / Quartile : Q1, Sujet : ECOLOGY

Résumé : 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 (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. Correspondence to: L. Merbold (lmerbold@bgc-jena.mpg.de) Values for maximum net carbon assimilation rates (photosynthesis) ranged from -12.5^molCO2 m-2 s-1 in a dry, open Millet cropland (C4-plants) up to -48^molCO2 m-2 s-1 for a tropical moist grassland. Maximum carbon assimilation rates were highly correlated with mean annual rainfall (r2=0.74). Maximum photosynthetic uptake rates (Fpmax) 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 dominated by C3-plants, showed a strong decrease in 30-min assimilation rates with increasing water vapour pressure deficit above 2.0 kPa.

Mots-clés Agrovoc : cycle du carbone, bilan hydrique, écosystème

Mots-clés géographiques Agrovoc : Afrique au sud du Sahara

Classification Agris : P40 - Météorologie et climatologie
F62 - Physiologie végétale - Croissance et développement
F40 - Écologie végétale

Champ stratégique Cirad : Axe 6 (2005-2013) - Agriculture, environnement, nature et sociétés

Auteurs et affiliations

• Merbold L., Max Planck Institut für Biogeochemie (DEU)
• Ardö Junas, Lund University (SWE)
• Arneth Almur, Lund University (SWE)
• Scholes Robert J., CSIR (ZAF)
• Nouvellon Yann, CIRAD-PERSYST-UPR Ecosystèmes de plantations (BRA) ORCID: 0000-0003-1920-3847
• De Grandcourt Agnès, CIRAD-PERSYST-UPR Ecosystèmes de plantations (COG)
• Archibald S., CSIR (ZAF)
• Bonnefond Jean-Marc, INRA (FRA)
• Boulain N., IRD (FRA)
• Brueggemann N., Institute of meteorology and climate research (DEU)
• Bruemmer C., University of British Columbia (CAN)
• Cappelaere Bernard, IRD (FRA)
• Ceschia Eric, CESBIO (FRA)
• El-Khidir H.A.M., El Obeid Research Station (SDN)
• El-Tahir B.A., El Obeid Research Station (SDN)
• Falk U., Universität Bonn (DEU)
• Lloyd Jon, University of Leeds (GBR)
• Kergoat Laurent, CESBIO (FRA)
• Le Dantec Valérie, CESBIO (FRA)
• Mougin Eric, CESBIO (FRA)
• Muchinda M., Zambia Meteorological Department (ZMB)
• Mukelabai M.M., Zambia Meteorological Department (ZMB)
• Ramier D., IRD (FRA)
• Roupsard Olivier, CIRAD-PERSYST-UPR Ecosystèmes de plantations (CRI) ORCID: 0000-0002-1319-142X
• Timouk F., CESBIO (FRA)
• Veenendaal Elmar M., Wageningen Agricultural University (NLD)
• Kutsch Werner L., Max Planck Institut für Biogeochemie (DEU)

Source : Cirad - Agritrop (https://agritrop.cirad.fr/551791/)

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