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@Article{AguilosHérBurWagBon:2018:WhDrLo,
               author = "Aguilos, Maricar and H{\'e}raultb, Bruno and Burban, Benoit and 
                         Wagner, Fabien Hubert and Bonal, Damien",
          affiliation = "{AgroParisTech-CIRAD-INRA-CNRS-Universit{\'e} de 
                         Guyane-Universit{\'e} des Antilles} and 
                         {AgroParisTech-CIRAD-INRA-CNRS-Universit{\'e} de 
                         Guyane-Universit{\'e} des Antilles} and 
                         {AgroParisTech-CIRAD-INRA-CNRS-Universit{\'e} de 
                         Guyane-Universit{\'e} des Antilles} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Universit{\'e} de Lorraine}",
                title = "What drives long-term variations in carbon flux and balance in a 
                         tropical rainforest in French Guiana?",
              journal = "Agricultural and Forest Meteorology",
                 year = "2018",
               volume = "253/254",
                pages = "114--123",
                month = "May",
             keywords = "Tropical rainforest, NEE, GPP. Ecosystem respiration, Radiation, 
                         Drought.",
             abstract = "A thorough understanding of how tropical forests respond to 
                         climate is important to improve ecosystem process models and to 
                         reduce uncertainties in current and future global carbon balance 
                         calculations. The Amazon rainforest, a major contributor to the 
                         global carbon cycle, is subject to strong intra- and interannual 
                         variations in climate conditions. Understanding their effect on 
                         carbon fluxes between the ecosystem and the atmosphere and on the 
                         resulting carbon balance is still incomplete. We examined the 
                         long-term (over a 12-year period; 20042015) variations in gross 
                         primary productivity (GPP), ecosystem respiration (RE) and net 
                         ecosystem exchange (NEE) in a tropical rainforest in French Guiana 
                         and identified key climatic drivers influencing the changes. The 
                         study period was characterized by strong differences in climatic 
                         conditions among years, particularly differences in the intensity 
                         of the dry and wet seasons, as well as differences in annual 
                         carbon fluxes and balance. Annual average GPP varied from 3384.9 g 
                         C m\−2 yr\‒1 (95% CI [3320.7, 3445.9]) to 4061.2 g C 
                         m\−2 yr\‒1 (95% CI [3980.1, 4145.0]). RE varied even 
                         more than GPP, with a difference of 933.1 C m\−2 
                         yr\‒1 between the minimum (3020.6 g C m\−2 
                         yr\‒1; 95% CI [2889.4, 3051.3]) and maximum (3953.7 g C 
                         m\−2 yr\‒1; 95% CI [3887.6, 4019.6]) values. 
                         Although NEE showed large interannual variability (nine-fold), 
                         from \‒65.6 g C m\−2 yr\‒1 (95% CI 
                         [\‒4.4, \‒126.0]) to \‒590.5 g C m\−2 
                         yr\‒1 (95% CI [\‒532.3, \‒651.6]), the forest 
                         remained a carbon sink over the 12-year period. A combination of 
                         global radiation (Rg), relative extractable water (REW) and soil 
                         temperature (Ts) explained 51% of the daily variations for GPP, 
                         30% for RE and 39% for NEE. Global radiation was always the best 
                         predictor of these variations, but soil water content and 
                         temperature did also influence carbon fluxes and balance. 
                         Seasonally, Rg was the major controlling factor for GPP, RE and 
                         NEE during the wet season. During the dry season, variations in 
                         carbon fluxes and balance were poorly explained by climate 
                         factors. Yet, REW was the key driver of variations in NEE during 
                         the dry season. This study highlights that, over the long-term, 
                         carbon fluxes and balance in such tropical rainforest ecosystems 
                         are largely controlled by both radiation and water limitation. 
                         Even though variations in Rg have a greater impact on these 
                         fluxes, water limitation during seasonal droughts is enough to 
                         reduce ecosystem productivity, respiration and carbon uptake. The 
                         reduced precipitation expected in tropical rainforest areas under 
                         future climatic conditions will therefore strongly influence 
                         carbon fluxes and carbon uptake. This study also highlights the 
                         importance for land surface or dynamic global vegetation models to 
                         consider the main drivers of carbon fluxes and balance separately 
                         for dry and wet seasons.",
                  doi = "10.1016/j.agrformet.2018.02.009",
                  url = "http://dx.doi.org/10.1016/j.agrformet.2018.02.009",
                 issn = "0168-1923",
             language = "en",
           targetfile = "aguilos_what.pdf",
        urlaccessdate = "29 nov. 2020"
}


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