ALBERT

Description: River systems connect the terrestrial biosphere, the atmosphere and the ocean in the global carbon cycle. A recent estimate suggests that up to 3 petagrams of carbon per year could be emitted as carbon dioxide (CO2) from global inland waters, offsetting the carbon uptake by terrestrial ecosystems. It is generally assumed that inland waters emit carbon that has been previously fixed upstream by land plant photosynthesis, then transferred to soils, and subsequently transported downstream in run-off. But at the scale of entire drainage basins, the lateral carbon fluxes carried by small rivers upstream do not account for all of the CO2 emitted from inundated areas downstream. Three-quarters of the world's flooded land consists of temporary wetlands, but the contribution of these productive ecosystems to the inland water carbon budget has been largely overlooked. Here we show that wetlands pump large amounts of atmospheric CO2 into river waters in the floodplains of the central Amazon. Flooded forests and floating vegetation export large amounts of carbon to river waters and the dissolved CO2 can be transported dozens to hundreds of kilometres downstream before being emitted. We estimate that Amazonian wetlands export half of their gross primary production to river waters as dissolved CO2 and organic carbon, compared with only a few per cent of gross primary production exported in upland (not flooded) ecosystems. Moreover, we suggest that wetland carbon export is potentially large enough to account for at least the 0.21 petagrams of carbon emitted per year as CO2 from the central Amazon River and its floodplains. Global carbon budgets should explicitly address temporary or vegetated flooded areas, because these ecosystems combine high aerial primary production with large, fast carbon export, potentially supporting a substantial fraction of CO2 evasion from inland waters.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Abril, Gwenael -- Martinez, Jean-Michel -- Artigas, L Felipe -- Moreira-Turcq, Patricia -- Benedetti, Marc F -- Vidal, Luciana -- Meziane, Tarik -- Kim, Jung-Hyun -- Bernardes, Marcelo C -- Savoye, Nicolas -- Deborde, Jonathan -- Souza, Edivaldo Lima -- Alberic, Patrick -- Landim de Souza, Marcelo F -- Roland, Fabio -- England -- Nature. 2014 Jan 16;505(7483):395-8. doi: 10.1038/nature12797. Epub 2013 Dec 15.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] Laboratoire Environnements et Paleoenvironnements Oceaniques et Continentaux (EPOC), CNRS, Universite Bordeaux 1, Avenue des Facultes, 33405 Talence, France [2] Laboratoire Geosciences et Environnement de Toulouse, Institut de Recherche pour le Developpement, Universite Paul Sabatier, 14 avenue Edouard Belin, 31400 Toulouse, France. ; Laboratoire Geosciences et Environnement de Toulouse, Institut de Recherche pour le Developpement, Universite Paul Sabatier, 14 avenue Edouard Belin, 31400 Toulouse, France. ; Laboratoire d'Oceanologie et Geosciences, CNRS, Universite du Littoral Cote d'Opale, 32 avenue Foch, 62930 Wimereux, France. ; Equipe Geochimie des Eaux, Institut de Physique du Globe de Paris, Universite Paris Diderot, Sorbonne Paris Cite, 35 rue Helene Brion, 75205 Paris Cedex 13, France. ; Laboratorio de Ecologia Aquatica, Departamento de Biologia, Universidade Federal de Juiz de Fora, Rua Jose Lourenco Kelmer, MG 36036-900 Juiz de Fora, Brazil. ; Laboratoire Biologie des Organismes et Ecosystemes Aquatiques (BOREA), Museum National d'Histoire Naturelle, CNRS, IRD, UPMC, 61 rue Buffon, 75005, Paris, France. ; NIOZ (Royal Netherlands Institute for Sea Research), Department of Marine Organic Biogeochemistry, Texel, 1790 AB Den Burg, The Netherlands. ; Programa de Geoquimica, Universidade Federal Fluminense, Outeiro Sao Joao Batista, RJ 24020015 Niteroi, Brazil. ; Laboratoire Environnements et Paleoenvironnements Oceaniques et Continentaux (EPOC), CNRS, Universite Bordeaux 1, Avenue des Facultes, 33405 Talence, France. ; Instituto de Geociencias, Universidade de Brasilia, Campus Universitario Darcy Ribeiro, DF 70.910-900 Brasilia, Brazil. ; Institut des Sciences de la Terre d'Orleans, 1A rue de la Ferollerie, 45071 Orleans Cedex 2, France. ; Laboratorio de Oceanografia Quimica, Universidade Estadual de Santa Cruz, Rodovia Ilheus-Itabuna, 45662-900 Ilheus, Bahia, Brazil.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24336199" target="_blank"〉PubMed〈/a〉