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| Aguilos, Maricar; Stahl, Clement; Burban, Benoit; Herault, Bruno; Courtois, Elodie; Coste, Sabrina; Wagner, Fabien; Ziegler, Camille; Takagi, Kentaro; Bonal, Damien. |
| Warmer and drier climates over Amazonia have been predicted for the next century with expected changes in regional water and carbon cycles. We examined the impact of interannual and seasonal variations in climate conditions on ecosystem-level evapotranspiration (ET) and water use efficiency (WUE) to determine key climatic drivers and anticipate the response of these ecosystems to climate change. We used daily climate and eddyflux data recorded at the Guyaflux site in French Guiana from 2004 to 2014. ET and WUE exhibited weak interannual variability. The main climatic driver of ET and WUE was global radiation (Rg), but relative extractable water (REW) and soil temperature (Ts) did also contribute. At the seasonal scale, ET and WUE showed a modal pattern... |
| Tipo: Text |
Palavras-chave: Tropical rainforest; Evapotranspiration; Water use efficiency; Drought; Radiation. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00484/59572/62542.pdf |
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| Belluardo, Francesco; Rosa, Gonçalo; Andreone, Franco; Courtois, Elodie; Lobón-rovira, Javier; Nussbaum, Ronald A; Raselimanana, Miary; Rasoazanany, Malalatiana; Raxworthy, Christopher; Crottini, Angelica. |
| Tipo: Text |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00682/79401/81943.pdf |
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| Van Langenhove, Leandro; Depaepe, Thomas; Vicca, Sara; Van Den Berge, Joke; Stahl, Clement; Courtois, Elodie; Weedon, James; Urbina, Ifigenia; Grau, Oriol; Asensio, Dolores; Peñuelas, Josep; Boeckx, Pascal; Richter, Andreas; Van Der Straeten, Dominique; Janssens, Ivan A.. |
| Background and aims Biological fixation of atmospheric nitrogen (N2) is the main pathway for introducing N into unmanaged ecosystems. While recent estimates suggest that free-living N fixation (FLNF) accounts for the majority of N fixed in mature tropical forests, the controls governing this process are not completely understood. The aim of this study was to quantify FLNF rates and determine its drivers in two tropical pristine forests of French Guiana. Methods We used the acetylene reduction assay to measure FLNF rates at two sites, in two seasons and along three topographical positions, and used regression analyses to identify which edaphic explanatory variables, including carbon (C), nitrogen (N), phosphorus (P) and molybdenum (Mo) content, pH, water... |
| Tipo: Text |
Palavras-chave: Free-living nitrogen fixation; Tropical forest; French Guiana; Nutrients; Phosphorus; Molybdenum. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00487/59901/63083.pdf |
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| Van Langenhove, Leandro; Janssens, Ivan A.; Verryckt, Lore; Brechet, Laetitia; Hartley, Iain P.; Stahl, Clement; Courtois, Elodie; Urbina, Ifigenia; Grau, Oriol; Sardans, Jordi; Peguero, Guille; Gargallo-garriga, Albert; Peñuelas, Josep; Vicca, Sara. |
| Theory states that tree growth in lowland tropical forests on old, weathered soils is limited by low phosphorous (P) availability. However, evidence for P limitation from nutrient manipulation experiments remains unclear, which raises the question whether trees are taking up added P. In French Guianese lowland rainforest, we measured changes in nitrogen (N) and P availability before and up to two months after N and P addition. We measured in soils with intact root systems and soils excluding roots and mycorrhizal fungi with root exclusion cylinders. When the root system was excluded, P addition increased P availability to a much greater extent and for a longer time than where the roots remained undisturbed. N dynamics were unaffected by root... |
| Tipo: Text |
Palavras-chave: Tropical forest; Phosphorus; Nitrogen; Fertilization; Root system; Plant root simulator probes. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00589/70161/68163.pdf |
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