Résumé
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 analysis showed that tree species were separated along PC 1 and PC 2 of detected P-containing compounds, which represented a continuum going from high concentrations of metabolites related to non-active P and P-storage, low total P concentrations and high N:P ratios, to high concentrations of P-containing metabolites related to energy and anabolic metabolism, high total P concentrations and low N:P ratios. These results highlight the species-specific use of P and the existence of species-specific P-use niches that are driven by the distinct species-specific position in a continuum in the P-allocation from P-storage compounds to P-containing molecules related to energy and anabolic metabolism.
Auteurs, date et publication :
Auteurs Albert Gargallo-Garriga , Jordi Sardans , Joan Llusià , Guille Peguero , Dolores Asensio , Romà Ogaya , Ifigenia Urbina , Leandro Van Langenhove , Lore T. Verryckt , Elodie A. Courtois , Clément Stahl , Oriol Grau , Otmar Urban , Ivan A. Janssens , Pau Nolis , Miriam Pérez-Trujillo , Teodor Parella , Josep Peñuelas
Publication : Molecules
Date : 2020
Volume : 25
Issue : 17
Pages : 3960
Catégorie(s)
#ANR-Citation #CIRAD #CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Emile Fonty , Corinne Sarthou , Denis Larpin , JEAN‐FRANÇOIS PONGE
Publication : Global Change Biology
Date : 2025
Volume : 15
Issue : 10
Pages : 2360-2374
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Biogeographic delineations within the European temperate mountains remain poorly understood, as there has been little effort to assemble and analyze vegetation relevés covering Pyrenees, Alps, Carpathians and Balkans altogether. Our study tackles this issue by focusing on the widely distributed alpine acidic grasslands dominated by Carex curvula. Cluster analysis of more than 800 vegetation relevés revealed the European-scale spatial patterns of vascular plant diversity in these alpine grasslands. The geographical distribution of floristic clusters was partly congruent with the physiography of European mountains. Southern European ranges (Southern Balkans and Pyrenees) exhibit a high level of endemism and corresponding floristic clusters are well separated from the others. Marked floristic similarities between the Easternmost Alps, the Carpathians, and the Northern Balkans (Stara Planina) supported a major floristic boundary that runs through the Austrian Alps and that is likely the legacy of a shared Quaternary history. Within the Alps, floristic clustering was mainly driven by ecological drivers and not geography. This paper presents the first detailed study of spatial patterns of species distribution within the European Alpine System, based on a comprehensive analysis of within- and between-community species diversity. It shows that the quantitative analysis of large and consistent data sets may question the traditional delineations of biogeographic regions within European mountains.
Auteurs, date et publication :
Auteurs Mihai Puşcaş , Philippe Choler
Publication : Flora - Morphology, Distribution, Functional Ecology of Plants
Date : 2025
Volume : 207
Issue : 3
Pages : 168-178
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Alpine glacier variations are known to be reliable proxies of Holocene climate. Here, we present a terrestrial cosmogenic nuclide (TCN)-based glacier chronology relying on 24 new 10Be exposure ages, which constrain maximum Neoglacial positions of four small to mid-sized glaciers (Rateau, Lautaret, Bonnepierre and Etages) in the Ecrins-Pelvoux massif, southern French Alps. Glacier advances, marked by (mainly lateral) moraine ridges that are located slightly outboard of the Little Ice Age (LIA, c. 12501860 AD) maximum positions, were dated to 4.25 ± 0.44 ka, 3.66 ± 0.09 ka, 2.09 ± 0.10 ka, c. 1.31 ± 0.17 ka and to 0.92 ± 0.02 ka. The ‘4.2 ka advance’, albeit constrained by rather scattered dates, is to our knowledge exposure-dated here for the first time in the Alps. It is considered as one of the first major Neoglacial advance in the western Alps, in agreement with other regional paleoclimatological proxies. We further review Alpine and Northern Hemisphere mid-to-high latitude evidence for climate change and glacier activity concomitant with the ‘4.2 ka event’. The ‘2.1 ka advance’ was not extensively dated in the Alps and is thought to represent a prominent advance in early Roman times. Other Neoglacial advances dated here match the timing of previously described Alpine Neoglacial events. Our results also suggest that a Neoglacial maximum occurred at Etages Glacier 0.9 ka ago, i.e. during the Medieval Climate Anomaly (MCA, c. 850-1250 AD). At Rateau Glacier, discordant results are thought to reflect exhumation and snow cover of the shortest moraine boulders. Overall, this study highlights the need to combine several sites to develop robust Neoglacial glacier chronologies in order to take into account the variability in moraine deposition pattern and landform obliteration and conservation.
Auteurs, date et publication :
Auteurs Melaine Le Roy , Philip Deline , Julien Carcaillet , Irene Schimmelpfennig , Magali Ermini
Publication : Quaternary Science Reviews
Date : 2025
Volume : 178
Pages : 118-138
Catégorie(s)
#CNRS #Lautaret #UGAAuteurs, date et publication :
Auteurs SR Gradstein , A Obregon , C Gehrig , J Bendix
Publication : Tropical Montane Cloud Forests: Science for Conservation and Management
Date : 2025
Pages : 130
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Rationale Producing robust high-frequency time series of raw atmospheric water vapor isotope data using laser spectrometry requires accurate calibration. In particular, the chemical composition of the analyzed sample gas can cause isotope bias. This study assesses the matrix effect on calibrated δ17O, δ18O, δ2H, 17O-excess, and d-excess values of atmospheric water vapor. Methods A Picarro L2140-i cavity ring-down spectrometer with an autosampler and a vaporizer is used to analyze δ17O, δ18O, δ2H, 17O-excess, and d-excess of two water standards. Isotope data obtained using synthetic air and dry ambient air as carrier gas at water mixing ratios ranging from 2000 to 30 000 ppmv are compared. Based on the results, atmospheric water vapor measurements are calibrated. The expected precision is estimated by Monte Carlo simulation. Results The dry air source strongly impacts raw isotope values of the two water standards but has no effect on the mixing ratio dependency functions. When synthetic air is used, δ17O, δ18O, and 17O-excess of calibrated atmospheric water vapor are overestimated by 0.6‰, 0.7‰, and 217 per meg, respectively, whereas δ2H and d-excess are underestimated by 1.5‰ and 7.3‰. Optimum precisions for the calibrated δ17O, δ18O, δ2H, 17O-excess, and d-excess values and 12 min integration time are 0.02‰, 0.03‰, 0.4‰, 14 per meg, and 0.4‰, respectively. Conclusions Regarding the obtained results, recommendations for the calibration of atmospheric water vapor isotope measurements are presented. The necessity to use dry ambient air as dry air source when running the standards for calibration is pointed out as a prerequisite for accurate atmospheric water vapor 17O-excess and d-excess measurements.
Auteurs, date et publication :
Auteurs Claudia Voigt , Christine Vallet-Coulomb , Clément Piel , Anne Alexandre
Publication : Rapid Communications in Mass Spectrometry
Date : 2025
Volume : 36
Issue : 6
Pages : e9227