Bi-decadal changes in nutrient concentrations and ratios in marine coastal ecosystems: The case of the Arcachon bay, France
Large amounts of nutrients have been released to the coastal ecosystems during the 20th century. Since then, management policies have been implemented and these amounts decreased in the economically developed countries. We examined the bi-decadal changes in nutrients (nitrate + nitrite, ammonium, orthophosphate and silicic acid) in the Arcachon bay, a semi-enclosed lagoon that hosts one of the largest but declining seagrass meadow in Europe. Seven sites have been sampled for nutrients and biogeochemical parameters during twenty years at low and/or high tide. In addition, continental and climatic data as well as hydro-climatic indices were used. Dynamic linear models were used to assess the bi-decadal changes in nutrient concentrations and ratios, their seasonality, and the bi-decadal changes of their potential drivers. Partial least square path modeling were used to investigate the relationships between potential abiotic drivers and nutrients. During the study period, the concentration of N and Si nutrients increased whereas the concentration of orthophosphate decreased, leading to deep changes in nutrient ratios. Clear relationships between abiotic drivers (local climate, continental inputs and the bay hydrodynamism) and N, P and Si nutrients were highlighted. However, the bi-decadal change in nutrient concentrations and ratios was mainly ascribed to the seagrass meadow decline through direct (less nutrient consumption) and indirect (increase in phytoplankton biomass) processes. Changes in temperature and wind direction may also influenced the nutrients concentrations through processes of remineralisation and flushing time, respectively. This study illustrates (1) the top-down control of seagrass on the nutrients concentrations and stoichiometry, and (2) the competition between primary producers (seagrass vs phytoplankton) for their nutrients resource.
(Progress in Oceanography. vol. 201, n° 0079-6611, 17/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IFREMER
Experimental Exposure to Tebuconazole Affects Metabolism and Body Condition in a Passerine Bird, the House Sparrow ( Passer domesticus )
Triazole compounds are among the most widely used fungicides in agroecosystems to protect crops from potential fungal diseases. Triazoles are suspected to have an impact on nontarget species due to their interactions with nonfungal sterol synthesis, and wild birds are likely to be contaminated by triazole fungicides because many of them live in agroecosystems. We experimentally tested whether exposure to environmental concentrations of a triazole could alter key integrative traits (metabolic rates and body condition) of an agroecosystem sentinel species, the house sparrow (Passer domesticus). Wild-caught adult sparrows were maintained in captivity and exposed (exposed group) or not (control group) for 7 continuous months to tebuconazole through drinking water. The metabolic rates of exposed and control sparrows were then measured at two different temperatures (12 °C and 25 °C), which correspond, respectively, to the thermoregulation and thermoneutrality temperatures of this species. We found that exposed sparrows had lower resting metabolic rates (i.e., measured at thermoneutrality, 25 °C) than controls. However, the thermoregulatory metabolic rates (i.e., measured at 12 °C) did not differ between exposed and control sparrows. Although the body mass and condition were not measured at the beginning of the exposure, sparrows at the time of the metabolic measurements 7 months after the onset of such exposure had a higher body condition than controls, supporting further the idea that tebuconazole affects metabolic functions. Our study demonstrates for the first time that the use of tebuconazole can alter metabolism and could potentially lead to adverse effects in birds
(Environmental Toxicology and Chemistry. vol. 41, n° 0730-7268, pp. 2500-2511, 17/06/2026)
CEBC, ULR, CNRS, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LCE, CNRS, UMLP, UBFC
Atmospheric Nitrous Acid Measurement in the French Landes Forest
(ACS Earth and Space Chemistry. vol. 6, n° 2472-3452, pp. 25-33, 17/06/2026)
IRCELYON-CARE, IRCELYON, UCBL, INC-CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LVEEM, UCA [2017-2020], CERI EE - IMT Nord Europe, IMT Nord Europe, IMT, IRCELYON, UCBL, INC-CNRS, CNRS
Évolutions paysagères et occupations humaines passées du Marais poitevin occidental durant la fin de l’Holocène
Dans le contexte actuel du changement climatique, l’analyse croisée de l’évolution paléoenvironnementale et paléosociétale d’un secteur littoral vulnérable illustre différentes formes d’occupations humaines liées à leur environnement durant les derniers millénaires. Une analyse sédimentologique couplée avec des cartographies historiques permet de reconstruire et de dater finement l’évolution des principaux paléopaysages de la bordure ouest du Marais poitevin. Cette analyse confirme que cet espace a profondément évolué, notamment durant l’Antiquité et le début du Moyen Âge, périodes durant lesquelles l’ancien golfe maritime s’est transformé en un marais aujourd’hui colmaté. En parallèle, l’évolution de l’occupation humaine historique est qualifiée par des données géoarchéologiques. Des vestiges d’anciennes pêcheries et empierrements ont été identifiés à proximité des points rocheux. Ils témoignent d’une occupation humaine historique dans les anciennes îles, au sein desquelles les Hommes se trouvaient en sécurité face aux aléas météo-marins.
(Géomorphologie : relief, processus, environnement. vol. 27, n° 1266-5304, pp. 263-278, 30/12/2021)
IGARUN, UN, LETG - Nantes, UNICAEN, NU, EPHE, PSL, UBO EPE, UR2, CNRS, IGARUN, UN, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UB, UFR HHAA, UN, CReAAH, UM, UR, UR2, CNRS, UFR HHAA, UN, MC
Les Auzières (Méthamis, Vaucluse)
(15/12/2021)
LAMPEA, AMU, CNRS, MC, IRAMAT-CRP2A, IRAMAT, UTBM, UO, UBM, CNRS, HNHP, MNHN, UPVD, CNRS, TRACES, EHESS, UT2J, Comue de Toulouse, MCC, Inrap, CNRS, CEPAM, UNS, CNRS, UniCA, PACEA, UB, CNRS, ADES, AMU, CNRS, EFS Alpes-Méditerranée, EFS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
The “Spaghetti Project”: the final identification guide to European Terebellidae (sensu lato) (Annelida, Terebelliformia)
This paper is the conclusion of the “Spaghetti Project” aiming to revise French species of Terebellidae sensu lato (s.l.) belonging to the five families: Polycirridae, Telothelepodidae, Terebellidae sensu stricto (s.s.), Thelepodidae and Trichobranchidae. During this project, 41 species were observed, 31 of them new for science: eight species of Polycirridae, eleven species of Terebellidae s.s., three species of Thelepodidae and nine species of Trichobranchidae. We provide a comprehensive key for all European species of terebellids with a focus on the important diagnostic characters for each family. Finally, we discuss issues on taxonomy, biodiversity and cryptic and pseudo-cryptic species of polychaetes in European waters, based on results obtained during this project.
(European Journal of Taxonomy. vol. 782, pp. 108-156, 14/12/2021)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UNIFESP, UMS POREA, INSU - CNRS, CNRS, INRAE, GU, SBR, SU, CNRS, FR2424, SBR, SU, CNRS, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, DYNECO, IFREMER, IUEM, IRD, INSU - CNRS, UBO EPE, CNRS, PatriNat, MNHN, CNRS, OFB, LIENSs, INSU - CNRS, ULR, CNRS, LECOB, SU, CNRS, OOB, SU, CNRS
Multidisciplinary assessment of nearshore nursery habitat restoration for an exploited population of marine fish
Nearshore habitats are essential for many marine fish species but are subject to anthropogenic stressors. Assessing the consequences of essential fish habitat degradation on population dynamics and productivity is challenging. We address this by focusing on a metapopulation of the common sole Solea solea , a high-value, exploited flatfish in the Eastern English Channel (EEC). Multidisciplinary data and expert knowledge were compiled to build feasible restoration scenarios for the availability of suitable habitat (measured in habitat surface extent) and chemical quality of juvenile habitats in the highly anthropized Seine estuary, the largest estuary and potentially a sole nursery area of primary interest in the EEC. Scenarios were simulated with a spatially structured life-cycle model to investigate the consequences of local restoration on restricted nursery habitats in the estuary. Restoring surface extent and habitat quality in the Seine estuary dramatically enhances spawning stock biomass (+18%) and fishery catches (+13%) in the EEC. Restoring habitat quality has a greater effect than restoring habitat surface. Because of the low connectivity between subpopulations of sole in the EEC, most of the local restoration benefits remain regional and affect the subpopulation that directly depends on the Seine nursery, with only moderate spread to the entire EEC. Our study emphasizes the utility of spatial simulation models for integrating multidisciplinary knowledge and assessing the consequences of local anthropogenic pressures at wider metapopulation scales. We provide a means of building robust methods to assess the benefits of nearshore habitat restoration for enhancing fish populations and fisheries and integrate habitat value into the sustainable management of exploited species.
(Marine Ecology Progress Series. vol. 680, n° 0171-8630, pp. 97-109, 09/12/2021)
ESE, INRAE, Institut Agro, Institut Agro, DYNECO, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEMAR, IRD, IFREMER, UBO EPE, CNRS, GIP-Seine-Aval
Are complementarity effects of species richness on productivity the strongest in species-rich communities?
How the relationship between species richness and productivity changes along environmental gradients remains poorly understood. We examined the context dependency of complementarity processes underpinning this relationship (biotic feedbacks, resource partitioning and facilitation) using the framework of Grime's (1973) humped-back model. We considered several scenarios of variation in competition and facilitation along environmental gradients, either monotonic with the most common or intense facilitation at the most abiotically severe end of gradients or nonlinear with the strongest facilitation at intermediate positions along gradients. How competition shifts to facilitation along environmental gradients is a key for determining where the effect of species richness on productivity occurs. Based on the literature, the original Stress Gradient Hypothesis would likely predict that complementarity effects should be the greatest, or the most important, in the most abiotically stressful environments. Alternatively, both the ‘collapse of facilitation’ and the ‘shift back to competition’ scenarios predict that the highest overall complementary effects on productivity, not biomass, would most likely occur at intermediate positions along environmental stress gradients, but this might vary depending on the source of stress. This latter prediction is consistent with a great deal of literature on natural gradients of productivity and species richness. Synthesis. Our predictions illustrate the importance of better understanding the context dependency of complementarity processes and the key role of facilitation along environmental gradients to better focus conservation efforts where ecosystem functioning is more likely to be negatively affected by species loss, in particular in species-rich communities. © 2021 British Ecological Society
(Journal of Ecology. vol. 109, n° 0022-0477, pp. 2038-2046, 01/12/2021)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Live (stained) benthic foraminifera from the West-Gironde Mud Patch (Bay of Biscay, NE Atlantic): Assessing the reliability of bio-indicators in a complex shelf sedimentary unit.
(Continental Shelf Research, n° 0278-4343, pp. 104616, 01/12/2021)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CHROME, UNIMES, OIST, LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France]
Early life neonicotinoid exposure results in proximal benefits and ultimate carryover effects
Neonicotinoids are insecticides widely used as seed treatments that appear to have multiple negative effects on birds at a diversity of biological scales. Adult birds exposed to a low dose of imidacloprid, one of the most commonly used neonicotinoids, presented reduced fat stores, delayed migration and potentially altered orientation. However, little is known on the effect of imidacloprid on birds growth rate despite studies that have documented disruptive effects of low imidacloprid doses on thyroid gland communication. We performed a 2×2 factorial design experiment in Zebra finches, in which nestling birds were exposed to a very low dose (0.205 mg kg body mass−1) of imidacloprid combined with food restriction during posthatch development. During the early developmental period, imidacloprid exposure resulted in an improvement of body condition index in treated nestlings relative to controls. Imidacloprid also led to compensatory growth in food restricted nestlings. This early life neonicotinoid exposure also carried over to adult age, with exposed birds showing higher lean mass and basal metabolic rate than controls at ages of 90–800 days. This study presents the first evidence that very low-dose neonicotinoid exposure during early life can permanently alter adult phenotype in birds.
(Scientific Reports. vol. 11, n° 2045-2322, 01/12/2021)
CEBC, ULR, CNRS, INRAE, CEN, ULaval, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS