Manioc : Portail | resultats 1 - 20 pour la recherche: Russell Bowen

An interview with Russell Bowen
Auteur(s) : Russell Bowen

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PCM 016 Russel Bown and PCM 040 Janice Scott: Panama Canal Zone 1964 Riots and Transition
Auteur(s) : PCM 016 Russel Bown, PCM 040 Janice Scott ( Interviewee ) Russel Bowen (PCM 016), Janice Scott (PCM 040), podcast created by Helen Miney ( Interviewer )

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The colony of British Guyana and its labouring population
Auteur(s) : Bronkhurst, Rév. H.V.P.
Année de publication :

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Rapport sur les questions coloniales adressé à M. le duc de Broglie,... à la suite d'un voyage fait aux Antilles et aux Guyanes pendant les années 1838 et 1839. Tome II, Documents et pièces justificatives. Deuxième partie, Etude de l'émancipation dans les colonies anglaises depuis l'année 1833 jusqu'au 3 décembre 1842
Auteur(s) : Lechevalier Saint-André, Jules (1806-1862)
Année de publication :

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Productivity, Respiration, and Light-Response Parameters of World Grassland and Agroecosystems Derived From Flux-Tower Measurements
Auteur(s) : Gilmanov, Tagir G. Aires, Luis Barcza, Zoltán Baron, V. S. Belelli, Luca Beringer, Jason Billesbach, D. Bonal, Damien
Auteurs secondaires : Department of Biology and Microbiology ; South Dakota State University (SDSTATE) University of Aveiro Department Meteorology [Budapest] ; Institute of Geography and Earth Sciences [Budapest] ; Eötvös Loránd University (ELTE) - Eötvös Loránd University (ELTE) Lacombe Research Centre ; Agriculture and Agri-Food [Ottawa] (AAFC) Tuscia University School of Geography and Environmental Scienc ; Monash University [Clayton] Department of Biological Systems Engineering ; University of Nebraska Ecologie des forêts de Guyane (ECOFOG) ; Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD) - Institut National de la Recherche Agronomique (INRA) - Université des Antilles et de la Guyane (UAG) - AgroParisTech - Centre National de la Recherche Scientifique (CNRS)

Éditeur(s) : HAL CCSD Society for Range Management
Résumé : Grasslands and agroecosystems occupy one-third of the terrestrial area, but their contribution to the global carbon cycle remains uncertain. We used a set of 316 site-years of CO(2) exchange measurements to quantify gross primary productivity, respiration, and light-response parameters of grasslands, shrublands/savanna, wetlands, and cropland ecosystems worldwide. We analyzed data from 72 global flux-tower sites partitioned into gross photosynthesis and ecosystem respiration with the use of the light-response method (Gilmanov, T. G., D. A. Johnson, and N. Z. Saliendra. 2003. Growing season CO(2) fluxes in a sagebrushsteppe ecosystem in Idaho: Bowen ratio/energy balance measurements and modeling. Basic and Applied Ecology 4:167-183) from the RANGEFLUX and WORLDGRASSAGRIFLUX data sets supplemented by 46 sites from the FLUXNET La Thuile data set partitioned with the use of the temperature-response method (Reichstein, M., E. Falge, D. Baldocchi, D. Papale, R. Valentini, M. Aubinet, P. Berbigier, C. Bernhofer, N. Buchmann, M. Falk, T. Gilmanov, A. Granier, T. Grunwald, K. Havrankova, D. Janous, A. Knohl, T. Laurela, A. Lohila, D. Loustau, G. Matteucci, T. Meyers, F. Miglietta, J.M. Ourcival, D. Perrin, J. Pumpanen, S. Rambal, E. Rotenberg, M. Sanz, J. Tenhunen, G. Seufert, F. Vaccari, T. Vesala, and D. Yakir. 2005. On the separation of net ecosystem exchange into assimilation and ecosystem respiration: review and improved algorithm. Global Change Biology 11: 1.424-1439). Maximum values of the quantum yield (alpha = 75 mmol.mol(-1)), photosynthetic capacity (A(max) = 3.4 mg CO(2) . m(-2).s-1), gross photosynthesis (P(g,max) = 1.16 g CO(2) . m(-2).d(-1)), and ecological light-use efficiency (epsilon(ecol) = 59 mmol . mol(-1)) of managed grasslands and high-production croplands exceeded those of most forest ecosystems, indicating the potential of nonforest ecosystems for uptake of atmospheric CO(2). Maximum values of gross primary production (8 600 g CO(2) . m(-2).yr(-1)), total ecosystem respiration (7 900 g CO(2) . m(-2).yr(-1)), and net CO(2) exchange (2 400 g CO(2) . m(-2).yr(-1)) were observed for intensively managed grasslands and high-yield crops, and are comparable to or higher than those for forest ecosystems, excluding some tropical forests. On average, 80% of the nonforest sites were apparent sinks for atmospheric CO(2), with mean net uptake of 700 g CO(2) . m(-2).yr(-1) for intensive grasslands and 933 g CO(2) . m(-2).d(-1) for croplands. However, part of these apparent sinks is accumulated in crops and forage, which are carbon pools that are harvested, transported, and decomposed off site. Therefore, although agricultural fields may be predominantly sinks for atmospheric CO(2), this does not imply that they are necessarily increasing their carbon stock.
ISSN: 1550-7424

hal-01190754
https://hal.archives-ouvertes.fr/hal-01190754
DOI : 10.2111/rem-d-09-00072.1
PRODINRA : 214043

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