Résumé
Earthworms are known to stimulate soil greenhouse gas (GHG) emissions, but the majority of previous studies have used simplified model systems or lacked continuous high-frequency measurements. To address this, we conducted a 2-year study using large lysimeters (5 m2 area and 1.5 m soil depth) in an ecotron facility, continuously measuring ecosystem-level CO2, N2O, and H2O fluxes. We investigated the impact of endogeic and anecic earthworms on GHG emissions and ecosystem water use efficiency (WUE) in a simulated agricultural setting. Although we observed transient stimulations of carbon fluxes in the presence of earthworms, cumulative fluxes over the study indicated no significant increase in CO2 emissions. Endogeic earthworms reduced N2O emissions during the wheat culture (− 44.6%), but this effect was not sustained throughout the experiment. No consistent effects on ecosystem evapotranspiration or WUE were found. Our study suggests that earthworms do not significantly contribute to GHG emissions over a two-year period in experimental conditions that mimic an agricultural setting. These findings highlight the need for realistic experiments and continuous GHG measurements.
Auteurs, date et publication :
Auteurs Oswaldo Forey , Joana Sauze , Clément Piel , Emmanuel S. Gritti , Sébastien Devidal , Abdelaziz Faez , Olivier Ravel , Johanne Nahmani , Laly Rouch , Manuel Blouin , Guénola Pérès , Yvan Capowiez , Jacques Roy , Alexandru Milcu
Publication : Scientific Reports
Date : 2023
Volume : 13
Issue : 1
Pages : 21920
Catégorie(s)
#ANR-Citation #CNRS #Ecotron de MontpellierRésumé
Despite the potential of subsoil carbon (C) to buffer or amplify climate change impacts, how fresh C and nutrients interact to control microorganismal effects on the C balance in deep soil horizons has yet to be determined. In this study, we aimed to estimate the impact of fresh C input at different soil depths on soil microbial activity. To conduct this study, Mediterranean soils from 3 layers (0–20, 20–50 and 50–100 cm of depth) were incubated over 28 days. Carbon and nutrient fluxes were measured after the addition of an amount of C equivalent to the postharvest root litter derived-C of a barley crop (4.3 atom% 13C), with and without nitrogen and phosphorus supply. We found that the microbial mineralization was C limited in the topsoil, while C and N colimited in the subsoil. These variations in stoichiometric constraints along the soil profile induced different microbial responses to C and/or nutrient addition. A stronger priming effect was observed in the topsoil than in the subsoil, and the sole C addition induced a negative C balance. Conversely, subsoil showed a positive C balance following fresh C addition, changing to critical soil C losses when nutrients were supplied with C. Our results show that fresh C input to subsoil (e.g., through deep-rooting crops) might foster soil C sequestration, but this positive effect can be reversed if such C inputs are combined with high nutrient availability (e.g., through fertilization), alleviating microbial limitation at depth.
Auteurs, date et publication :
Auteurs Lorène Siegwart , Gabin Piton , Christophe Jourdan , Clément Piel , Joana Sauze , Soh Sugihara , Isabelle Bertrand
Publication : Geoderma
Date : 2023
Volume : 440
Pages : 116729
Catégorie(s)
#CNRS #Ecotron de MontpellierRésumé
Peatlands are an important carbon (C) reservoir storing one-third of global soil organic carbon (SOC), but little is known about the fate of these C stocks under climate change. Here, we examine the impact of warming and elevated atmospheric CO2 concentration (eCO2) on the molecular composition of SOC to infer SOC sources (microbe-, plant- and fire-derived) and stability in a boreal peatland. We show that while warming alone decreased plant- and microbe-derived SOC due to enhanced decomposition, warming combined with eCO2 increased plant-derived SOC compounds. We further observed increasing root-derived inputs (suberin) and declining leaf/needle-derived inputs (cutin) into SOC under warming and eCO2. The decline in SOC compounds with warming and gains from new root-derived C under eCO2, suggest that warming and eCO2 may shift peatland C budget towards pools with faster turnover. Together, our results indicate that climate change may increase inputs and enhance decomposition of SOC potentially destabilising C storage in peatlands.
Auteurs, date et publication :
Auteurs Nicholas O. E. Ofiti , Michael W. I. Schmidt , Samuel Abiven , Paul J. Hanson , Colleen M. Iversen , Rachel M. Wilson , Joel E. Kostka , Guido L. B. Wiesenberg , Avni Malhotra
Publication : Nature Communications
Date : 2023
Volume : 14
Issue : 1
Pages : 7533
Catégorie(s)
#CNRS #Ecotron IleDeFrance #ENSRésumé
The genus Tamphana Schaus, 1892 is revised. The transfer of Tamphana from Bombycidae to Apatelodidae is confirmed. The study, based on examination of habitus, genitalia, and barcoding, leads to the separation of the various species currently placed within Tamphana into two distinct genera. Examination of genitalia of specimens supposedly belonging to the species T. marmorea Schaus, 1892 revealed strikingly different characters leading to description of nine new species: T. awa n. sp. from Maranhão, Brazil, T. ampliata n. sp. from Costa Rica, Panama, Venezuela and Ecuador, T. picobonitensis n. sp. from Honduras and Costa Rica, T. furtadoi n. sp. from Mato Grosso, Brazil, T. lauriei n. sp. from Belize, T. lucifer n. sp. from French Guiana, T. paranensis n. sp. from Brazil (Minas Gerais and Paraná), T. tikuna n. sp. from Colombia, Peru and Brazil (Amazonas), T. tripertita n. sp. from French Guiana. The adults and genitalia of all the new species are figured. A lectotype for Tamphana marmorea is here designated and figured. In the genus Tuyvae Orlandin, Piovesan & Carneiro, 2024, recently published, to the two already described species: Tuyvae maoma (Schaus, 1920) and Tuyvae orion (Dognin, 1916), two additional new species are described: Tuyvae douglasboyesi n. sp. from Colombia and Tuyvae carabaya n. sp. from Peru. A lectotype for Tuyvae orion is here designated and figured.
Auteurs, date et publication :
Auteurs Daniel Herbin , Alessandro Giusti , Carlos G. C. Mielke
Publication : Faunitaxys
Date : 2025
Volume : 12
Issue : 61
Pages : 1-31
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Cleistes rosea and 10 other taxa comprise a complex widely distributed in various open vegetation types from eastern South America to Panama. The taxonomic identity of most of these taxa is unclear and their relationships with C. rosea have never been satisfactorily discussed or tested. Here, we employ molecular phylogenetics, morphometrics and morphological, ecological and geographic distribution data to investigate the relationships and taxonomy of Cleistes rosea and related species. Our results confirm that Cleistes rosea and Cleistes castaneoides are sister species and although highly similar in general floral morphology, they differ in vegetative characters, distribution, habitat, floral scent, and lip characters. Both species show local variations regarding floral characters, particularly the flower colour, and such differences were used here to delimit infraspecific taxa within the C. rosea/C. castaneoides clade. While C. rosea var. guianensis var. nov. is restricted to French Guiana, and C. rosea var. buenaventurae stat. & comb. nov. is restricted to low altitudes on the western side of the Cordillera Occidental in the Choco region of Colombia, C. castaneoides var. castaneoides and C. castaneoides var. augusta comb. nov. are sympatric throughout their distribution. Cleistes abdita, formerly known as C. rosea f. pallida, is similar to C. castaneoides but distinguished by the smaller flowers and restricted distribution to Amazonian savannas. Cleistes rosea is distributed throughout the north of the Andes and northern South America. In turn, C. castaneoides occurs mainly in South-eastern and Central-western Brazil. Still, the distribution of these three species overlaps in the Guiana Shield, where the differentiation between them is less evident. Our results provide evidence of the plasticity of the floral morphology of Cleistes, especially the lip, and highlight that hitherto neglected characters, such as vegetative morphology, habitat, and floral scent, are particularly informative for the characterization of species and taxonomy of the genus.
Auteurs, date et publication :
Auteurs João Aguiar Nogueira Batista , Cristian Castro , Aurélien Sambin , Gabriela Cruz-Lustre , Emerson Ricardo Pansarin
Publication : Systematics and Biodiversity
Date : 2023
Volume : 21
Issue : 1
Pages : 2207575
Catégorie(s)
#CNRS #FORET NouraguesRésumé
In the high Arctic, thermal bridging through frozen shrub branches has been demonstrated to cool the ground by up to 4°C during cold spells, affecting snow metamorphism and soil carbon and nutrients. In alpine conditions, the thermal conductivity contrast between shrub branches and snow is much less than in the Arctic, so that the importance of thermal bridging is uncertain. We explore this effect by monitoring ground temperature and liquid water content under green alders and under nearby alpine tundra in the Alps. During a January 2022 cold spell, the ground temperature at 5 cm depth under alders is 1.3°C colder than under alpine tundra. Ground water freezing under alders is complete, while water remains liquid under tundra. Finite element simulations reproduce the observed temperature difference between both sites, showing that thermal bridging does affect ground temperature also under Alpine conditions.
Auteurs, date et publication :
Auteurs Florent Domine , Kevin Fourteau , Philippe Choler
Publication : Geophysical Research Letters
Date : 2023
Volume : 50
Issue : 24
Pages : e2023GL105100
Catégorie(s)
#CNRS #Lautaret #UGARésumé
Introduction
In contrast to the dynamics observed in plant/pathogen interactions, endophytic fungi have the capacity to establish enduring associations within their hosts, leading to the development of a mutually beneficial relationship that relies on specialized chemical interactions. Research indicates that the presence of endophytic fungi has the ability to significantly modify the chemical makeup of the host organism. Our hypothesis proposes the existence of a reciprocal exchange of chemical signals between plants and fungi, facilitated by specialized chemical processes that could potentially manifest within the tissues of the host. This research aimed to precisely quantify the portion of the cumulative fungal endophytic community's metabolome detectable within host leaves, and tentatively evaluate its relevance to the host-endophyte interplay. The understory palm Astrocaryum sciophilum (Miq.) Pulle was used as a interesting host plant because of its notable resilience and prolonged life cycle, in a tropical ecosystem.
Method
Using advanced metabolome characterization, including UHPLC-HRMS/MS and molecular networking, the study explored enriched metabolomes of both host leaves and 15 endophytic fungi. The intention was to capture a metabolomic "snapshot" of both host and endophytic community, to achieve a thorough and detailed analysis.
Results and discussion
This approach yielded an extended MS-based molecular network, integrating diverse metadata for identifying host- and endophyte-derived metabolites. The exploration of such data (>24000 features in positive ionization mode) enabled effective metabolome comparison, yielding insights into cultivable endophyte chemodiversity and occurrence of common metabolites between the holobiont and its fungal communities. Surprisingly, a minor subset of features overlapped between host leaf and fungal samples despite significant plant metabolome enrichment. This indicated that fungal metabolic signatures produced in vitro remain sparingly detectable in the leaf. Several classes of primary metabolites were possibly shared. Specific fungal metabolites and/or compounds of their chemical classes were only occasionally discernible in the leaf, highlighting endophytes partial contribution to the overall holobiont metabolome. To our knowledge, the metabolomic study of a plant host and its microbiome has rarely been performed in such a comprehensive manner. The general analytical strategy proposed in this paper seems well-adapted for any study in the field of microbial- or microbiome-related MS and can be applied to most host-microbe interactions.
Auteurs, date et publication :
Auteurs Leonie Pellissier , Arnaud Gaudry , Salomé Vilette , Nicole Lecoultre , Adriano Rutz , Pierre-Marie Allard , Laurence Marcourt , Emerson Ferreira Queiroz , Jérôme Chave , Véronique Eparvier , Didier Stien , Katia Gindro , Jean-Luc Wolfender
Publication : Frontiers in Plant Science
Date : 2023
Volume : 14
Pages : 1278745
Catégorie(s)
#CNRS #FORET NouraguesAuteurs, date et publication :
Auteurs Jérémie Lapèze , Carlos Lopez-Vaamonde
Publication : Faunitaxys
Date : 2025
Volume : 12
Issue : 3
Pages : 1-23
Catégorie(s)
#CNRS #FORET NouraguesRésumé
The biodiversity of tropical rainforest is difficult to assess. Yet, its estimation is necessary for conservation purposes, to evaluate our level of knowledge and the risks faced by the forest in relation to global change. Our contribution is to estimate the regional richness of tree species from local but widely spread inventories. We reviewed the methods available, which are nonparametric estimators based on abundance or incidence data, log-series extrapolation and the universal species-area relationship based on maximum entropy. Appropriate methods depend on the scale considered. Harte’s self-similarity model is suitable at the regional scale, while the log-series extrapolation is not. GuyaDiv is a network of forest plots installed over the whole territory of French Guiana, where trees over 10 cm DBH are identified. We used its information (1315 species censused in 68 one-hectare plots) to estimate the exponent of the species-area relationship, assuming Arrhenius’s power law. We could then extrapolate the number of species from three local, wide inventories (over 2.5 km2). We evaluated the number of tree species around 2200 over the territory.
Auteurs, date et publication :
Auteurs Eric Marcon , Ariane Mirabel , Jean-François Molino , Daniel Sabatier
Publication : Journal of Tropical Ecology
Date : 2025
Volume : 40
Pages : e11
Catégorie(s)
#CNRS #FORET NouraguesRésumé
Earthworms can stimulate microbial activity and hence greenhouse gas (GHG) emissions from soils. However, the extent of this effect in the presence of plants and soil moisture fluctuations, which are influenced by earthworm burrowing activity, remains uncertain. Here, we report the effects of earthworms (without, anecic, endogeic, both) and plants (with, without) on GHG (CO2, N2O) emissions in a 3-month greenhouse mesocosm experiment simulating a simplified agricultural context. The mesocosms allowed for water drainage at the bottom to account for the earthworm engineering effect on water flow during two drying-wetting cycles. N2O cumulative emissions were 34.6% and 44.8% lower when both earthworm species and only endogeic species were present, respectively, and 19.8% lower in the presence of plants. The presence of the endogeic species alone or in combination with the anecic species slightly reduced CO2 emissions by 5.9% and 11.4%, respectively, and the presence of plants increased emissions by 6%. Earthworms, plants and soil water content interactively affected weekly N2O emissions, an effect controlled by increased soil dryness due to drainage via earthworm burrows and mesocosm evapotranspiration. Soil macroporosity (measured by X-ray tomography) was affected by earthworm species-specific burrowing activity. Both GHG emissions decreased with topsoil macropore volume, presumably due to reduced moisture and microbial activity. N2O emissions decreased with macropore volume in the deepest layer, likely due to the presence of fewer anaerobic microsites. Our results indicate that, under experimental conditions allowing for plant and earthworm engineering effects on soil moisture, earthworms do not increase GHG emissions, and endogeic earthworms may even reduce N2O emissions.
Auteurs, date et publication :
Auteurs Pierre Ganault , Johanne Nahmani , Yvan Capowiez , Nathalie Fromin , Ammar Shihan , Isabelle Bertrand , Bruno Buatois , Alexandru Milcu
Publication : PloS One
Date : 2025
Volume : 19
Issue : 2
Pages : e0289859