Consulta: creatorFacets:"Urbina, Ifigenia"
Registros recuperados: 5
Data/hora: 04/06/2024 02:38:03

Regulation of nitrogen fixation from free-living organisms in soil and leaf litter of two tropical forests of the Guiana shield
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Rapid root assimilation of added phosphorus in a lowland tropical rainforest of French Guiana
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: 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

Different “metabolomic niches” of the highly diverse tree species of the French Guiana rainforests
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Gargallo-garriga, Albert; Sardans, Jordi; Granda, Victor; Llusià, Joan; Peguero, Guille; Asensio, Dolores; Ogaya, Romà; Urbina, Ifigenia; Van Langenhove, Leandro; Verryckt, Lore T.; Chave, Jérome; Courtois, Elodie A.; Stahl, Clément; Grau, Oriol; Klem, Karel; Urban, Otmar; Janssens, Ivan A.; Peñuelas, Josep.
Tropical rainforests harbor a particularly high plant diversity. We hypothesize that potential causes underlying this high diversity should be linked to distinct overall functionality (defense and growth allocation, anti-stress mechanisms, reproduction) among the different sympatric taxa. In this study we tested the hypothesis of the existence of a metabolomic niche related to a species-specific differential use and allocation of metabolites. We tested this hypothesis by comparing leaf metabolomic profiles of 54 species in two rainforests of French Guiana. Species identity explained most of the variation in the metabolome, with a species-specific metabolomic profile across dry and wet seasons. In addition to this “homeostatic” species-specific metabolomic...
Tipo: Text
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00625/73686/73151.pdf

31P-NMR Metabolomics Revealed Species-Specific Use of Phosphorous in Trees of a French Guiana Rainforest
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Gargallo-garriga, Albert; Sardans, Jordi; Llusià, Joan; Peguero, Guille; Asensio, Dolores; Ogaya, Romà; Urbina, Ifigenia; Langenhove, Leandro Van; Verryckt, Lore T.; Courtois, Elodie A.; Stahl, Clément; Grau, Oriol; Urban, Otmar; Janssens, Ivan A.; Nolis, Pau; Pérez-trujillo, Miriam; Parella, Teodor; Peñuelas, Josep.
Productivity of tropical lowland moist forests is often limited by availability and functional allocation of phosphorus (P) that drives competition among tree species and becomes a key factor in determining forestall community diversity. We used non-target 31P-NMR metabolic profiling to study the foliar P-metabolism of trees of a French Guiana rainforest. The objective was to test the hypotheses that P-use is species-specific, and that species diversity relates to species P-use and concentrations of P-containing compounds, including inorganic phosphates, orthophosphate monoesters and diesters, phosphonates and organic polyphosphates. We found that tree species explained the 59% of variance in 31P-NMR metabolite profiling of leaves. A principal component...
Tipo: Text
Palavras-chave: P-31-NMR metabolic profiling; Iceland; Tropical lowland; P-containing compounds; Species-specific P-use niches.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00648/76023/76922.pdf

Nutrient scarcity strengthens soil fauna control over leaf litter decomposition in tropical rainforests
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Peguero, Guille; Sardans, Jordi; Asensio, Dolores; Fernández-martínez, Marcos; Gargallo-garriga, Albert; Grau, Oriol; Llusià, Joan; Margalef, Olga; Márquez, Laura; Ogaya, Romà; Urbina, Ifigenia; Courtois, Elodie A.; Stahl, Clément; Van Langenhove, Leandro; Verryckt, Lore T.; Richter, Andreas; Janssens, Ivan A.; Peñuelas, Josep.
Soil fauna is a key control of the decomposition rate of leaf litter, yet its interactions with litter quality and the soil environment remain elusive. We conducted a litter decomposition experiment across different topographic levels within the landscape replicated in two rainforest sites providing natural gradients in soil fertility to test the hypothesis that low nutrient availability in litter and soil increases the strength of fauna control over litter decomposition. We crossed these data with a large dataset of 44 variables characterizing the biotic and abiotic microenvironment of each sampling point and found that microbe-driven carbon (C) and nitrogen (N) losses from leaf litter were 10.1 and 17.9% lower, respectively, in the nutrient-poorest site,...
Tipo: Text
Palavras-chave: Biogeochemistry; Extracellular enzyme activity; Litter decomposition; Nutrients; Soil fauna.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00513/62424/69469.pdf