Auteurs, date et publication :
Auteurs Julian Donald , Mélanie Roy , Uxue Suescun , Amaia Iribar , Sophie Manzi , Léonie Péllissier , Philippe Gaucher , Jérôme Chave
Publication : Journal of Ecology
Date : 2025
Catégorie(s)
#ANR-Citation #CNRS #FORET NouraguesRésumé
Abstract. The role that soil, foliage, and atmospheric dynamics have on surface carbonyl sulfide (OCS) exchange in a Mediterranean forest ecosystem in southern France (the Oak Observatory at the Observatoire de Haute Provence, O3HP) was investigated in June of 2012 and 2013 with essentially a top-down approach. Atmospheric data suggest that the site is appropriate for estimating gross primary production (GPP) directly from eddy covariance measurements of OCS fluxes, but it is less adequate for scaling net ecosystem exchange (NEE) to GPP from observations of vertical gradients of OCS relative to CO2 during the daytime. Firstly, OCS and carbon dioxide (CO2) diurnal variations and vertical gradients show no net exchange of OCS at night when the carbon fluxes are dominated by ecosystem respiration. This contrasts with other oak woodland ecosystems of a Mediterranean climate, where nocturnal uptake of OCS by soil and/or vegetation has been observed. Since temperature, water, and organic carbon content of soil at the O3HP should favor the uptake of OCS, the lack of nocturnal net uptake would indicate that its gross consumption in soil is compensated for by emission processes that remain to be characterized. Secondly, the uptake of OCS during the photosynthetic period was characterized in two different ways. We measured ozone (O3) deposition velocities and estimated the partitioning of O3 deposition between stomatal and non-stomatal pathways before the start of a joint survey of OCS and O3 surface concentrations. We observed an increasing trend in the relative importance of the stomatal pathway during the morning hours and synchronous steep drops of mixing ratios of OCS (amplitude in the range of 60–100ppt) and O3 (amplitude in the range of 15–30ppb) after sunrise and before the break up of the nocturnal boundary layer. The uptake of OCS by plants was also characterized from vertical profiles. However, the time window for calculation of the ecosystem relative uptake (ERU) of OCS, which is a useful tool for partitioning measured NEE, was limited in June 2012 to a few hours after midday. This was due to the disruption of the vertical distribution of OCS by entrainment of OCS rich tropospheric air in the morning and because the vertical gradient of CO2 reverses when it is still light. Moreover, polluted air masses (up to 700ppt of OCS) produced dramatic variation in atmospheric OCS∕CO2 ratios during the daytime in June 2013, further reducing the time window for ERU calculation.
Auteurs, date et publication :
Auteurs Sauveur Belviso , Ilja Marco Reiter , Benjamin Loubet , Valérie Gros , Juliette Lathière , David Montagne , Marc Delmotte , Michel Ramonet , Cerise Kalogridis , Benjamin Lebegue , Nicolas Bonnaire , Victor Kazan , Thierry Gauquelin , Catherine Fernandez , Bernard Genty
Publication : Atmospheric Chemistry and Physics
Date : 2016
Volume : 16
Issue : 23
Pages : 14909-14923
Catégorie(s)
#CNRS #FORET O3HPRésumé
Tropical forests are characterized by large carbon stocks and high biodiversity, but they are increasingly threatened by human activities. Since structure strongly influences the functioning and resilience of forest communities and ecosystems, it is important to quantify it at fine spatial scales. Here, we propose a new simulation-based approach, the “Canopy Constructor”, with which we quantified forest structure and biomass at two tropical forest sites, one in French Guiana, the other in Gabon. In a first step, the Canopy Constructor combines field inventories and airborne lidar scans to create virtual 3D representations of forest canopies that best fit the data. From those, it infers the forests' structure, including crown packing densities and allometric scaling relationships between tree dimensions. In a second step, the results of the first step are extrapolated to create virtual tree inventories over the whole lidar-scanned area. Across the French Guiana and Gabon plots, we reconstructed empirical canopies with a mean absolute error of 3.98 m [95% credibility interval: 3.02, 4.98], or 14.4%, and a small upwards bias of 0.66 m [−0.41, 1.8], or 2.7%. Height-stem diameter allometries were inferred with more precision than crown-stem diameter allometries, with generally larger heights at the Amazonian than the African site, but similar crown-stem diameter allometries. Plot-based aboveground biomass was inferred to be larger in French Guiana with 400.8 t ha−1 [366.2–437.9], compared to 302.2 t ha−1 in Gabon [267.8–336.8] and decreased to 299.8 t ha−1 [275.9–333.9] and 251.8 t ha−1 [206.7–291.7] at the landscape scale, respectively. Predictive accuracy of the extrapolation procedure had an RMSE of 53.7 t ha−1 (14.9%) at the 1 ha scale and 87.6 t ha−1 (24.2%) at the 0.25 ha scale, with a bias of −17.1 t ha−1 (−4.7%). This accuracy was similar to regression-based approaches, but the Canopy Constructor improved the representation of natural heterogeneity considerably, with its range of biomass estimates larger by 54% than regression-based estimates. The Canopy Constructor is a comprehensive inference procedure that provides fine-scale and individual-based reconstructions even in dense tropical forests. It may thus prove vital in the assessment and monitoring of those forests, and has the potential for a wider applicability, for example in the exploration of ecological and physiological relationships in space or the initialisation and calibration of forest growth models.
Auteurs, date et publication :
Auteurs Fabian Jörg Fischer , Nicolas Labrière , Grégoire Vincent , Bruno Hérault , Alfonso Alonso , Hervé Memiaghe , Pulchérie Bissiengou , David Kenfack , Sassan Saatchi , Jérôme Chave
Publication : Remote Sensing of Environment
Date : 2025
Volume : 251
Pages : 112056
Catégorie(s)
#ANR-Citation #CNRS #FORET NouraguesRésumé
Intrahepatic cholangiocarcinoma (iCCA) is a deadly liver primary cancer associated with poor prognosis and limited therapeutic opportunities. Active transforming growth factor beta (TGFβ) signaling is a hallmark of the iCCA microenvironment. However, the impact of TGFβ on the transcriptome of iCCA tumor cells has been poorly investigated. Here, we have identified a specific TGFβ signature of genes commonly deregulated in iCCA cell lines, namely HuCCT1 and Huh28. Novel coding and noncoding TGFβ targets were identified, including a TGFβ-induced long noncoding RNA (TLINC), formerly known as cancer susceptibility candidate 15 (CASC15). TLINC is a general target induced by TGFβ in hepatic and nonhepatic cell types. In iCCA cell lines, the expression of a long and short TLINC isoform was associated with an epithelial or mesenchymal phenotype, respectively. Both isoforms were detected in the nucleus and cytoplasm. The long isoform of TLINC was associated with a migratory phenotype in iCCA cell lines and with the induction of proinflammatory cytokines, including interleukin 8, both in vitro and in resected human iCCA. TLINC was also identified as a tumor marker expressed in both epithelial and stroma cells. In nontumor livers, TLINC was only expressed in specific portal areas with signs of ductular reaction and inflammation. Finally, we provide experimental evidence of circular isoforms of TLINC, both in iCCA cells treated with TGFβ and in resected human iCCA. Conclusion: We identify a novel TGFβ-induced long noncoding RNA up-regulated in human iCCA and associated with an inflammatory microenvironment. (Hepatology Communications 2018;2:254-269)
Auteurs, date et publication :
Auteurs Aude Merdrignac , Gaëlle Angenard , Coralie Allain , Kilian Petitjean , Damien Bergeat , Pascale Bellaud , Allain Fautrel , Bruno Turlin , Bruno Clément , Steven Dooley , Laurent Sulpice , Karim Boudjema , Cédric Coulouarn
Publication : Hepatology Communications
Date : 2025
Volume : 2
Issue : 3
Pages : 254-269
Catégorie(s)
#CNRS #EcoGenO #Université de RennesAuteurs, date et publication :
Auteurs Henry A Hespenheide
Publication : The Coleopterists Bulletin
Date : 2025
Volume : 72
Issue : 1
Pages : 113-118
Catégorie(s)
#CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Michael S Caterino , Alexey K Tishechkin
Publication : ZooKeys
Date : 2025
Issue : 557
Pages : 59
Catégorie(s)
#⛔ No DOI found #CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs H van der Werff
Publication : Blumea-Biodiversity, Evolution and Biogeography of Plants
Date : 2025
Volume : 56
Issue : 3
Pages : 214-215
Catégorie(s)
#CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Daniel A Truchado , José Manuel Diaz-Piqueras , Esperanza Gomez-Lucia , Ana Doménech , Borja Milá , Javier Pérez-Tris , Jonas Schmidt-Chanasit , Daniel Cadar , Laura Benítez
Publication : Viruses
Date : 2025
Volume : 11
Issue : 12
Pages : 1148
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Metagenomics is helping to expand the known diversity of viruses, especially of those with poorly studied hosts in remote areas. The Neotropical region harbors a considerable diversity of avian species that may play a role as both host and short-distance vectors of unknown viruses. Viral metagenomics of cloacal swabs from 50 Neotropical birds collected in French Guiana revealed the presence of four complete astrovirus genomes. They constitute an early diverging novel monophyletic clade within the Avastrovirus phylogeny, representing a putative new astrovirus species (provisionally designated as Avastrovirus 5) according to the International Committee on Taxonomy of Viruses (ICTV) classification criteria. Their genomic organization shares some characteristics with Avastrovirus but also with Mamastrovirus. The pan-astrovirus RT-PCR analysis of the cloacal samples of 406 wild Neotropical birds showed a community-level prevalence of 4.9% (5.1% in passerines, the highest described so far in this order of birds). By screening birds of a remote region, we expanded the known host range of astroviruses to the avian families Cardinalidae, Conopophagidae, Furnariidae, Thamnophilidae, Turdidae and Tyrannidae. Our results provide important first insights into the unexplored viral communities, the ecology, epidemiology and features of host-pathogen interactions that shape the evolution of avastroviruses in a remote Neotropical rainforest.
Auteurs, date et publication :
Auteurs Izaskun Fernández-Correa , Daniel A. Truchado , Esperanza Gomez-Lucia , Ana Doménech , Javier Pérez-Tris , Jonas Schmidt-Chanasit , Daniel Cadar , Laura Benítez
Publication : Scientific Reports
Date : 2025
Volume : 9
Issue : 1
Pages : 9513
Catégorie(s)
#CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Holger Teichert , Stefan Dötterl , Dawn Frame , Alexander Kirejtshuk , Gerhard Gottsberger
Publication : Flora-Morphology, Distribution, Functional Ecology of Plants
Date : 2025