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| Bayon, Germain; Schefuss, Enno; Dupont, Lydie; Borges, Alberto V.; Dennielou, Bernard; Lambert, Thibault; Mollenhauer, Gesine; Monin, Laurence; Ponzevera, Emmanuel; Skonieczny, Charlotte; Andre, Luc. |
| There is increasing evidence that abrupt vegetation shifts and large-scale erosive phases occurred in Central Africa during the third millennium before present. Debate exists as to whether these events were caused by climate change and/or intensifying human activities related to the Bantu expansion. In this study, we report on a multi-proxy investigation of a sediment core (KZR-23) recovered from the Congo submarine canyon. Our aim was to reconstruct climate, erosion and vegetation patterns in the Congo Basin for the last 10,000 yrs, with a particular emphasis on the late Holocene period. Samples of modern riverine suspended particulates were also analyzed to characterize sediment source geochemical signatures from across the Congo watershed. We find that... |
| Tipo: Text |
Palavras-chave: Neodymium isotopes; Suspended particulates; Congo Basin; ENSO; Human land-use; Deforestation. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00463/57467/59747.pdf |
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| Rochelle-newall, Emma. J.; Winter, Christian; Barrón, Cristina; Borges, Alberto V.; Duarte, Carlos M.; Elliott, Mike; Frankignoulle, Michel; Gazeau, Frederic; Middelburg, Jack J.; Pizay, Marie-dominique; Gattuso, Jean-pierre. |
| Knowing the metabolic balance of an ecosystem is of utmost importance in determining whether the system is a net source or net sink of carbon dioxide to the atmosphere. However, obtaining these estimates often demands significant amounts of time and manpower. Here we present a simplified way to obtain an estimation of ecosystem metabolism. We used artificial neural networks (ANNs) to develop a mathematical model of the gross primary production to community respiration ratio (GPP:CR) based on input variables derived from three widely contrasting European coastal ecosystems (Scheldt Estuary, Randers Fjord, and Bay of Palma). Although very large gradients of nutrient concentration, light penetration, and organic-matter concentration exist across the sites,... |
| Tipo: Text |
Palavras-chave: Artificial neural networks; Coastal ecosystems; Metabolic balance; Primary production; Respiration. |
| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00247/35857/34378.pdf |
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| Borges, Alberto V.; Abril, Gwenael; Darchambeau, Francois; Teodoru, Cristian R.; Deborde, Jonathan; Vidal, Luciana O.; Lambert, Thibault; Bouillon, Steven. |
| Carbon emissions to the atmosphere from inland waters are globally significant and mainly occur at tropical latitudes. However, processes controlling the intensity of CO2 and CH4 emissions from tropical inland waters remain poorly understood. Here, we report a data-set of concurrent measurements of the partial pressure of CO2 (pCO(2)) and dissolved CH4 concentrations in the Amazon (n = 136) and the Congo (n = 280) Rivers. The pCO(2) values in the Amazon mainstem were significantly higher than in the Congo, contrasting with CH4 concentrations that were higher in the Congo than in the Amazon. Large-scale patterns in pCO(2) across different lowland tropical basins can be apprehended with a relatively simple statistical model related to the extent of wetlands... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00603/71528/69955.pdf |
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| Regnier, Pierre; Friedlingstein, Pierre; Ciais, Philippe; Mackenzie, Fred T.; Gruber, Nicolas; Janssens, Ivan A.; Laruelle, Goulven G.; Lauerwald, Ronny; Luyssaert, Sebastiaan; Andersson, Andreas J.; Arndt, Sandra; Arnosti, Carol; Borges, Alberto V.; Dale, Andrew W.; Gallego-sala, Angela; Godderis, Yves; Goossens, Nicolas; Hartmann, Jens; Heinze, Christoph; Ilyina, Tatiana; Joos, Fortunat; Larowe, Douglas E.; Leifeld, Jens; Meysman, Filip J. R.; Munhoven, Guy; Raymond, Peter A.; Spahni, Renato; Suntharalingam, Parvadha; Thullner, Martin. |
| A substantial amount of the atmospheric carbon taken up on land through photosynthesis and chemical weathering is transported laterally along the aquatic continuum from upland terrestrial ecosystems to the ocean. So far, global carbon budget estimates have implicitly assumed that the transformation and lateral transport of carbon along this aquatic continuum has remained unchanged since pre-industrial times. A synthesis of published work reveals the magnitude of present-day lateral carbon fluxes from land to ocean, and the extent to which human activities have altered these fluxes. We show that anthropogenic perturbation may have increased the flux of carbon to inland waters by as much as 1.0 Pg C yr(-1) since pre-industrial times, mainly owing to enhanced... |
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| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00264/37508/36764.pdf |
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