Kleptoplastidic benthic foraminifera from aphotic habitats: insights into assimilation of inorganic C, N and S studied with sub-cellular resolution
(Environmental Microbiology, n° 1462-2912, 01/01/2019)
LPG-ANGERS, LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS, WHOI, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EPFL
Holocene chronostratigraphy of northeastern Baffin Bay based on radiocarbon and palaeomagnetic data
The northeastern Baffin Bay continental margin, which experiences high sediment accumulation rates, is an excellent location to study Holocene sedimentary variations. However, it is often difficult to obtain reliable chronologies of the sediment archives using traditional methods (d 18 O and radiocarbon) due to specific oceanographic conditions (e.g. corrosive bottom waters). Here we propose a chronostratigraphy of three cores collected on the northwestern Greenland margin (AMD14-204, AMD14-210 and AMD14-Kane2B) based on a combination of radiocarbon dating and palaeomagnetic records. Geophysical properties of discrete samples were used to verify the reliability of the palaeomagnetic records. Palaeomagnetic analyses indicate a strong and stable natural remanent magnetization carried by low coercivity ferrimagnetic minerals (magnetite) in the pseudo-single domain grain size range. Correlation of the full palaeomagnetic vector (inclination, declination, and relative palaeointensity) was used to establish a reliable chronostratigraphical framework for two of the cores (AMD14-204 and AMD14-210) and to propose an original palaeomagnetic record for the previously 14 C-dated core AMD14-Kane2B that covers most of the Holocene. Overall, this new chronostratigraphy allowed improvement of the timing of the main palaeoenvi-ronmental changes that occurred in this area during the Holocene.
(Boreas. vol. 48, n° 0300-9483, pp. 147-165, 01/01/2019)
ISMER, UQAR, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Intratidal and Subtidal Circulation in a Tropical Estuary during Wet Season: The Maroni, French Guiana
Observations of water level, current velocity, river discharge, wind and salinity were collected in the Maroni estuary, on the border of French Guiana and Suriname during the wet season of 2018 to explore subtidal circulation patterns. Measurements are complimented by the application of analytical models with an aim to diagnose forcing mechanisms responsible for producing subtidal flows during the day of data collection and to extrapolate these findings to other time periods with variable wind and river forcing. Subtidal along-channel flows were found to be dominated by river discharge, with seaward directed velocities found throughout the channel section reaching 40 cm s −1. This pattern was altered with strong southwesterly winds, which produced and inverse gravitational circulation pattern despite the elevated river discharge. Secondary, or cross-channel flows, displayed a three-layer vertical structure in the main channel due to a combination of channel curvature and tidal asymmetry in the lateral baroclinic pressure gradient. The pressure gradient was produced by a salinity intrusion front that only manifested in the channel during flood tide. This is the first comprehensive study of tidal and subtidal flow dynamics in the Maroni estuary.
(Journal of Marine Science and Engineering. vol. 7, n° 2077-1312, pp. 433, 24/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LEEISA, IFREMER, UG, CNRS, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS
Mécanismes : échanges de polluants aux interfaces sol-végétation-atmosphère et devenir dans l’atmosphère
(pp. 73-106, 24/04/2026)
ECOSYS, INRA, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, SADAPT, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Modeling the Impact of the Implementation of a Submerged Structure on Surf Zone Sandbar Dynamics
Coastal defense strategies based on structures are increasingly unpopular as they are costly, leave lasting scars on the landscape, and sometimes have limited effectiveness or even adverse impacts. While a clear improvement concerning aesthetic considerations using soft submerged breakwater is undeniable, their design has often focused on wave transmission processes across the crest of the structure, overlooking short- to medium-term morphodynamic responses. In this study, we used a time- and depth-averaged morphodynamic model to investigate the impact of the implementation of a submerged breakwater on surf zone sandbar dynamics at the beach of Sete, SE France. The hydrodynamic module was calibrated with data collected during a field experiment using three current profilers deployed to capture rip-cell circulation at the edge of the structure. The model showed good agreement with measurements, particularly for the longshore component of the flow (RMSE = 0.07 m/s). Results showed that alongshore differential wave breaking at the edge of the submerged breakwater drove an intense (0.4 m/s) two-dimensional circulation for low- to moderate-energy waves. Simulations indicated that inner-bar rip channel development, which was observed prior to the submerged reef implementation, was inhibited in the lee of the structure as rip-cell circulation across the inner bar disappeared owing to persistently low-energy breaking waves. The cross-shore sandbar dynamics in the lee of the structure were also impacted due to the drastic decrease of the offshore-directed flow over the inner-bar during energetic events. This paper highlights that implementation of a submerged breakwater results in larges changes in nearshore hydrodynamics that, in turn, can affect overall surf zone sandbar behavior.
(Journal of Marine Science and Engineering. vol. 7, n° 2077-1312, pp. 117, 24/04/2026)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Impact of diuron and S-metolachlor on the freshwater diatom Gomphonema gracile: Complementarity between fatty acid profiles and different kinds of ecotoxicological impact-endpoints
Fatty acids (FA) are crucial for the maintenance of membrane fluidity and play a central role in metabolic energy storage. Polyunsaturated fatty acids play an essential ecological role since they are key parameters in the nutritional value of algae. Pesticide impacts on fatty acid profiles have been documented in marine microalgae, but remain understudied in freshwater diatoms. The aims of this study were to: 1) investigate the impact of diuron and S-metolachlor on "classical descriptors" (photosynthesis, growth rate, pigment contents, and on the expression levels of target genes in freshwater diatoms), 2) examine the impact of these pesticides on diatom fatty acid profiles and finally, 3) compare fatty acid profiles and "classical descriptor" responses in order to evaluate their complementarity and ecological role. To address this issue, the model freshwater diatom Gomphonema gracile was exposed during seven days to diuron and S-metolachlor at 10 µg.L.
(Science of the Total Environment. vol. 688, n° 0048-9697, pp. 960-969, 24/04/2026)
UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LBM, UB, CNRS
Transcriptomic response of the benthic freshwater diatom Nitzschia palea exposed to Few Layer Graphene
Nanotechnology currently undergoes a rising development partly due to the increasing use of carbon-based nanoparticles, such as Few Layer Graphene (FLG). Owing to their numerous applications, their industrial production is likely to lead to environmental release, including into aquatic ecosystems. In this study, a transcriptomic approach was used to assess the effect of FLG at low (0.1 mg.L-1) and high (50 mg.L-1) concentration on the benthic freshwater diatom Nitzschia palea after 48h of exposure. Direct contact with FLG and induced shading were distinguished to compare the transcriptomic responses. Differentially expressed genes between each exposure and control conditions were identified and their functional description was discussed. Slight transcriptomic response related to cell wall repair was observed in diatoms exposed to low FLG concentration. Exposure to high FLG concentration induced a strong response involving 1907 transcripts. Notably, 16 transcripts involved in chlorophyll biosynthesis process were under-expressed (Log2FoldChange between -3 and -1.2),suggesting a down-regulation of photosynthetic metabolism. Diatoms exposed to high FLG concentration over-expressed about 13 transcripts encoding for extracellular proteins playing a role in cellular adhesion, and two highly up-regulated transcripts involved in cell wall repair. Light deprivation caused by shading induced a down-regulation of genes involved in the energetic metabolism of N. palea. Overall, these results revealed that metabolic pathways impacted by FLG exposure were concentration contact-dependent. Moreover, this study suggests that low FLG concentration, close to environmental conditions, will have minor impact on diatom biofilms whereas high FLG concentration, mimicking accidental release, might be critical for ecosystems.
(Environmental science.Nano. vol. 6, n° 2051-8153, pp. 1363-1381, 24/04/2026)
LEFE, INEE-CNRS, CNRS, UT3, Comue de Toulouse, CNRS, Toulouse INP, Comue de Toulouse, GBF, INRA, ENSAT, INP-ENSAT, AgroToulouse, INP-AgroToulouse, Toulouse INP, Comue de Toulouse, Toulouse INP, Comue de Toulouse, CIRIMAT, UT3, Comue de Toulouse, IUT Toulouse Auch Castres, UT3, Comue de Toulouse, INC-CNRS, CNRS, Toulouse INP, Comue de Toulouse, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Dispersion des métaux de la mine au lagon : rôle du compartiment atmosphérique et dispersion au sein du compartiment biotique dulçaquicole et estuarien. Rapport scientifique final
Ce rapport du programme DMML « Dispersion des métaux de la mine au lagon » constitue le volume 1 (sur 4) du programme intégré « Dispersion et exposition humaine aux métaux en Nouvelle-Calédonie » composé de 3 projets (DMML, Dynamine, Métexpo) étudiant les métaux et leur toxicité sur des sites pilotes similaires.- Le programme DMML a proposé de caractériser le potentiel de dispersion des éléments métalliques traces (ETM) Ni, Cr, Co et Mn au sein des compartiments abiotiques (atmosphère et pédosphère) et d’évaluer la contamination métallique dans le compartiment biotique de l’hydrosphère ainsi que de déterminer les mécanismes de transferts trophiques. - La caractérisation des flux d’ETM au sein de l’hydrosphère est réalisée dans le programme « Dynamine ».
(pp. 192 p., 24/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ISEA, UNC, ARTeHiS, MCC, UB, CNRS, GSMA, URCA, CNRS
Devenir des micropolluants et bioindicateur lipidique en Zone de rejet végétalisée
(pp. 18, 24/04/2026)
UR REVERSAAL, IRSTEA, UB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IRSTEA
Protective Effects of and Aqueous Extracts against Cadmium- and Mercury-Induced Toxicities
The extracts of and are widely used in the folk medicine. The potential protective effects of these extracts have been evaluated against cadmium in the yeast , and against mercurial contamination in zebrafish . In yeast, both extracts efficiently protected the Δ mutant strain exposed to cadmium chloride restoring the growth, the expression of stress-response genes and decreasing the level of oxidative stress. In zebrafish, the supplementation of methylmercury-contaminated diet with both plant extracts similarly protected fish through the suppression of the methylmercury-induced lipid peroxidation, decrease of acetylcholinesterase activity, and restoring the expression levels of stress-response genes. This study particularly demonstrates the protective potential of both aqueous extracts against methylmercury, and could represent an interesting alternative for the Amazonian fish-eating communities to cope with the impact of chronic exposure to contaminated diets.
(Toxicological Research. vol. 35, n° 1976-8257, pp. 25-35, 24/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UFOPA