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Plasticity in the brooding cidaroid Ctenocidaris nutrix : a morphological, trophic, and molecular investigation.
No full textInternational audiencePhenotypic plasticity refers to the capacity of an organism’s phenotype to vary in response to changes in environmental conditions, without any change in the individual genotype. Sea urchins (Echinoidea) are well-known for their morphological and behavioural plasticity in response to changing habitats or trophic environments. Phenotypic plasticity has been little studied in directly developing species, in which low levels of phenotypic plasticity are usually expected as a consequence of high levels of genetic differentiation among populations and local genetic adaptation. In the present work, we report a significant plasticity in the direct-developing and brooding sub-Antarctic species Ctenocidaris ( Eurocidaris ) nutrix (Echinoidea, Cidaridae) through morphological and trophic analyses of gut contents and δ 13 C and δ 15 N isotopic compositions. Molecular data (COI mtDNA) confirm that the different phenotypes of C. nutrix , the short-spined C. nutrix nutrix and the long-spined C. nutrix longispina , are a single species restricted to sub-Antarctic waters. As formerly demonstrated in broadcasting echinoid species, morphological plasticity appears to be mainly linked to depth and swell exposure, specimens from exposed and shallow sites showing shorter spines and larger apical systems compared to specimens from sheltered or deep sites. Significant differences in the diet and trophic niche of the different phenotypes suggest that prey type and food diversity may also be a factor promoting distinct phenotypic responses, both in the feeding behaviour and morphology of echinoids
Spectral induced polarization monitoring of toluene biodegradation by Rhodococcus wratislaviensis in controlled laboratory conditions
No full textInternational audienceThe global prevalence of organic pollutants presents a significant environmental challenge, necessitating sustainable remediation strategies. In situ biodegradation emerges as a cost-effective and eco-friendly solution. However, the real-time monitoring of in situ bacterial activities, particularly biodegradation processes, remains a challenge due to the limitations of traditional intrusive methods, including issues of representativeness, reproducibility and high-associated costs. Spectral induced polarization (SIP) has shown sensitivity to surface changes in subsurface environments, especially for biogeochemical reactivity monitoring including those associated with biodegradation. Despite this potential, advances have to be made to quantitatively link SIP parameters to in situ biodegradation processes. This study addresses this gap by conducting controlled biogeophysical experiments on a sand-packed column undergoing biodegradation facilitated by Rhodococcus wratislaviensis IFP 2006. SIP measurements were paired with bacterial growth kinetics to develop a quantitative model estimating bacterial growth. The results demonstrate that SIP, coupled with routine laboratory measurements, can effectively and quantitatively assess bacterial growth and the biodegradation of organic pollutants. These findings highlight the potential of SIP as a non-intrusive and reliable method for monitoring biodegradation in contaminated subsurface environments
The Caravan Roads and Way Stations in North-West Arabia (CaRoWS) Project. Report on the 2025 Season.
No full textThis is the report of the 2025 fieldwork season undertaken by the CaRoWS project in the Saudi Arabian Ḥismā. It contains several chapters : on the Greek, Early Islamic, Ancient North Arabian and Nabataean as well Developing Arabic inscriptions. They are preceded by an introduction and followed by a general commentary. It contains also appendices, among which maps, a list of sites and a catalogue of the new Nabataean and Nabataeo-Arabic inscriptions. 33 plates illustrate the report.Ceci est le rapport de la campagne 2025 du projet CaRoWS dans la Ḥismā saoudienne. Il comprend plusieurs chapitres consacrés aux inscriptions grecques, arabes, nord-arabiques anciennes, nabatéennes et nabatéo-arabes. Il comprend également une introduction et un commentaire général.Le rapport contient aussi des annexes, parmi lesquelles des cartes, une liste des sites et un catalogue des nouvelles inscriptions nabatéennes et nabatéo-arabes. L'ensemble est par ailleurs illustré de 33 planches
Les nouvelles intendances environnementales : coopérer, « hacker », jouer la transformation écologique dans nos territoires
No full textInternational audienceCet article propose une restitution d’une série de résidences de réflexions transdisciplinaires sur les « Nouvelles intendances des territoires » et sur les « Territoires vivants » dans le contexte du changement climatique et de la transition écologique. Ces résidences, initiées et réalisées de 2021 à 2024 dans le cadre des différentes éditions du Festival « Agir pour le Vivant » à Arles, ont exploré des approches innovantes de gouvernance, de participation citoyenne, et de relations entre humains et non-humains. Divers chercheurs ou experts en écologie, agronomie, sciences sociales et humanités environnementales, architecture et conservation de la nature mais aussi des élus et activistes ont présenté des études de cas et conduit des analyses croisées. Les défis de la confiance, du piratage des règles, du dialogue, de la prise en compte des dimensions spirituelles et émotionnelles, et du renouvellement des récits et des modes de penser sont identifiés. Le théâtre-forum apparaît comme un outil pertinent pour jouer, délibérer au sujet des enseignements de ces résidences et pour favoriser la rencontre entre l’action collective et l’action publique
Une écriture “excentrique” : l’exemple de Furukawa Hideo: An “Eccentric” Form of Writing: The Case of Furukawa Hideo
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A safari across France: soil fauna insights from a nationwide soil quality monitoring program
No full textInternational audienceSoil biodiversity is fundamental to ecosystem functioning but remains underrepresented in conservation policies and large-scale monitoring. Here, we present RMQS-Biodiversity, a nationwide soil biodiversity survey integrated into the French Soil Quality Monitoring Network (RMQS), and illustrate its potential for soil ecology research. In this pioneer study, we examine three major ecological aspects: (i) how systematic grid-based sampling captures micro-food web patterns using nematode communities, (ii) the spatial turnover of detritivore communities (Collembola, Isopoda, Diplopoda) in response to environmental and geographic gradients, and (iii) the influence of macroecological drivers on predator (Carabidae) morphological traits. Across 69 sites, we identified a few widespread species coexisting with numerous rare taxa, underscoring the value of large-scale surveys for detecting cryptic biodiversity. Nematode indicators revealed high variability in food web structure across land uses, with increased facultative phytophagous nematodes in forests. Isopods and diplopods were strongly structured by dispersal constraints, while springtails exhibited weaker environmental responses, likely due to their higher dispersal capacity. Additionally, sexual size dimorphism in Carabidae varied by habitat, with female-biased dimorphism in closed habitats but no dimorphism in open environments, highlighting habitat stability's role in shaping morphological traits. This study demonstrates the value of multi-taxon, multi-trophic biodiversity assessments in long-term soil monitoring. RMQS-Biodiversity provides a robust framework for soil biodiversity monitoring and conservation, refining bioindicators of soil quality and informing policies such as the EU Soil Monitoring Law
First evidence of deleterious effect of pesticide mixture on health status in semi-captive grey partridges
No full textInternational audiencePesticides are mainly used in agroecosystems to control pests. Due to their limited specificity, the resulting widespread contamination may cause unintended effects on non-target organisms that use these habitats. While increasing attention is paid to the relationship between single substances and phenotype on non-target species, their combined impacts are still largely unknown. Since interactions between pesticides may also impact organisms' health, studying them as complex mixtures is the more realistic approach. Here, we present the first experimental study testing the relationship between an environmentally relevant pesticide mixture and health biomarkers on a farmland avian non-target model. To do so, we used 40 semi-captive grey partridges (Perdix perdix) fed for five months with conventional grains. Their plant protection product (PPP) load (i.e., the number of PPPs, the total sum of scaled pesticide concentrations and the total toxicity index) in blood and proxies of health status (evaluated using behavioral and physiological features) were monitored at the end of the exposure period. We demonstrated, for the first time, concerning correlations between PPP load indexes and bird healthrelated features (physical activity, flight initiation distance, eye ring redness and acetylcholinesterase activity). Overall, we highlighted the urgent need to consider environmentally-relevant PPP mixture when biomonitoring non-target vertebrates in ecotoxicological studies.</div