Particle size distribution of nitrated and oxygenated polycyclic aromatic hydrocarbons (NPAHs and OPAHs) on traffic and suburban sites of a European megacity : Paris (France)
The size distribution of particulate nitrated and oxygenated polycyclic aromatic hydrocarbons (NPAHs and OPAHs) was determined during two field campaigns at a traffic site in summer 2010 and at a suburban site during the MEGAPOLI (Megacities : 5 Emissions, urban, regional and Global Atmospheric POLlution and climate effects, and Integrated tools for assessment and mitigation) experiment in summer 2009. Both, OPAHs and NPAHs were strongly associated (>85 %) to fines particles (Dp < 2.5 µm) increasing the interest of their study on a sanitary point of view. Results showed really different NPAH and OPAH particle size distributions between both sites. At traffic site, 10 clearly bimodal (notably for NPAHs) particle size distributions (Dp = 0.14 and 1.4 µm) were observed, while the particle size distributions were more scattered at the suburban site, especially for OPAHs. Bimodal particle size distribution observed at traffic site for the NPAH could be assigned to the vehicle emissions and the particle resuspension. Broadest distribution observed at the suburban site could be attributed to the 15 mass transfer of compounds by volatilization/sorption processes during the transport of particles in the atmosphere. Results also showed that the combination of the study of particle size distributions applied to marker compounds (primary : 1-nitropyrene ; secondary : 2-nitrofluoranthene) and to NPAH or OPAH chemical profiles bring some indications on their primary and/or secondary origin. Indeed, 1,4-anthraquinone seemed 20 only primary emitted by vehicles while 7-nitrobenz[a]anthracene, benz[a]antracen7,12- dione and benzo[b]fluorenone seemed secondarily formed in the atmosphere.
(Atmospheric Chemistry and Physics. vol. 12, n° 1680-7316, pp. 8877-8887, 13/04/2026)
INERIS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
A new breaking wave height direct estimator from video imagery
Breaker height is a key parameter of nearshore processes and the demand for a continuous remote estimator is pressing. In this paper we present a standalone remote video-based method that estimates wave height at the breakpoint. Individual breaking events are first identified from changes in optical properties and wave height is further derived from the optical signature at the onset of breaking. An extended validation is performed using a dense wave basin dataset. The results show the ability of the method to measure individual breaker heights (9% of mean error, 18% RMS). In addition, the unique combination of in situ and remotely sensed data allows the estimation of two other breaking-related parameters, the height-to-depth ratio and wave front face slope, which show a substantial amount of dispersion. Because nearshore video systems are rapidly spreading over world coasts, this low-cost remote breaker height estimator should encounter large interest in coastal engineering studies.
(Coastal Engineering. vol. 61, n° 0378-3839, pp. 42-48, 13/04/2026)
PUC, LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, UTFSM, LEGI, UJF, Grenoble INP, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
La variabilité climatique rapide de la dernière période glaciaire et l’extinction des Néandertaliens
(pp. 107-121, 13/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, PACEA, UB, CNRS
Influence of Hydrological Parameters on Organohalogenated Micropollutant (Polybrominated Diphenyl Ethers and Polychlorinated Biphenyls) Behaviour in the Seine (France)
The temporal dynamics of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were investigated in a heavily urbanized river (Seine River, Paris, France) from November 2009 to May 2010. Pollutant concentrations were in the range of 0.2 to 3.8 ng l(-1) (median 1.1) and 0.4 to 3.6 ng l(-1) (median 1.1) for a tri-deca BDEs and a 7PCBs, respectively. In addition, for both PBDEs and PCBs, the partitioning between the particulate and dissolved phases was investigated. Due to their low water solubility, PBDEs were mainly (> 70%) bound to particles. In contrast, only 54% of a 7PCBs occurred in the particulate phase, and their partitioning was influenced by the degree of chlorination. During the sampling period, PBDE/PCB fluxes were quite similar and ranged from 3 to 128 and from 6 to 125 g day(-1), respectively. The annual mass flow of PBDEs and PCBs was estimated to 10 kg for both. Contrary to PCBs and BDE-209, the temporal evolution of a tri-hepta BDEs was related to particulate organic matter content, which is controlled by river flow variations. This suggests that they exhibit different sources or behavior in the Seine River.
(Archives of Environmental Contamination and Toxicology. vol. 62, n° 0090-4341, pp. 570-578, 13/04/2026)
SISYPHE, UPMC, EPHE, PSL, PSL, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Climatically-controlled siliceous productivity in the eastern Gulf of Guinea during the last 40 000 yr
Opal content and diatom assemblages were analysed in core GeoB4905-4 to reconstruct siliceous productivity changes in the eastern Gulf of Guinea during the last 40 000 yr. Opal and total diatom accumulation rates presented low values over the considered period, except during the Last Glacial Maximum and between 15 000 calendar years Before Present (15 cal. ka BP) and 5.5 cal. ka BP, the so-called African Humid Period, when accumulation rates of brackish and freshwater diatoms at the core site were highest. Conversely, accumulation rates of windblown diatoms exhibited an opposite pattern with higher values before and after the African Humid Period and greatest values during Heinrich Events, the Younger Dryas and since 5.5 cal. ka BP. Our results demonstrate that siliceous productivity in the eastern Gulf of Guinea was directly driven by the nutrient load from local rivers, whose discharges were forced by precipitation changes over western Equatorial Africa and/or modification of the fluvio-deltaic systems forced by sea level changes. Precipitation in this region is controlled by the West African monsoon which is, in turn, partly dependent on the presence and intensity of the Atlantic Cold Tongue (ACT). Our results therefore suggest that the ACT was weakened, warmer trade winds were less vigorous, and cloud convec-tion and precipitation were greater during the AHP though centennial-to-millennial timescale dry events were observed at ∼10 cal. ka BP, ∼8.5 cal. ka BP and ∼6 cal. ka BP. Conversely , the ACT was more intense, trade winds were more vigorous and African climate was more arid during H1, the Younger Dryas and after 5.5 cal. ka BP into the present.
(Climate of the Past. vol. 8, n° 1814-9324, pp. 415-431, 13/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IACT, CSIC, UGR, CAU
Evidence for a Complex Relationship between Antibiotics and Antibiotic-Resistant Escherichia Coli: From Medical Center Patients to a Receiving Environment
The aim of this study was to investigate the relationship between antibiotics and antibiotic-resistant fecal bacteria (E. coli) in water along a medical center−wastewater treatment plant−river continuum (4 km). A multiresidue chemical analysis methodology, using solid phase extraction coupled with liquid chromatography tandem mass spectrometry, was performed to detect whether low levels of contamination by 34 antibiotics were related to antibiotic resistance of E. coli and antibiotic use. The contamination of water by antibiotics and antibiotic-resistant E. coli decreased along the continuum. Although amoxicillin was predominantly prescribed, only ofloxacin (1 ng*L−1) and sulfamethoxazole (4 ng*L−1) persisted in the river. At the retirement home, in the medical center, even though no tetracycline and sulfamethoxazole were consumed, the highest occurrences of antibiotic resistance were in classes of quinolones (42.0%), sulfonamides (24.0%), tetracyclines (38.0%), and penicillins (38.0%), mainly due to the presenceof multiple antibiotic-resistance genes on class 1 integrons. Along the continuum, the occurrence of E. coli resistant to antibiotics and those carrying class 1 integrons decreased in water samples (p-value <0.001). Interestingly, in the river, only persistent antibiotic compounds (ofloxacin, sulfamethoxazole) were found, but they did not correspond to the major resistances (tetracycline, amoxicillin) of E. coli.
(Environmental Science and Technology. vol. 46, n° 0013-936X, pp. 1859−1868, 13/04/2026)
M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, SCALE, ULH, NU, UNIROUEN, NU, CNRS
Remediation of a watershed contaminated by heavy metals: A 2-year field biomonitoring of periphytic biofilms
This study focuses on an industrial contamination site subjected to remediation processes since 2007 in the Riou-Mort watershed (southw st France). The purpose was to assess the first impacts of remediation on periphytic biofilms, and was performed during two years of biomonitoring. Periphytic biofilms were collected on glass slides immersed 24 days at different sites along the contamination gradient for 12 colonisation cycles. Metal contaminations (Cd and Zn) were analysed in biofilms and the evolution of diatom communities was assessed, integrating teratology quantifications. Despite remediation work initiated at the industrial site, this study demonstrated the persistence of metal contamination in water, as well as in biofilms. In addition, our data, showed that the remediation process was initially marked by an increase in metal contamination in the river, with increasing diatom community shifts. Metal-contaminated biofilms presented decreasing species diversities and were dominated by metal-resistant species such as Eolimna minima, whom abundances increased in 2010 reaching 57.2 ± 10%. No significant decrease in metal accumulation was observed and total Cd content in biofilms collected downstream the industrial site ranged from 772.7 ± 88 in July 2009 to 636.9 ± 20 μg/gDW in July 2 010. Results obtained on artificial substrates were compared with those of natural substrates and showed similar diatom communities and abundances of deformed diatoms but lower diversities. This ensured that glass slide subtrates gave a good representation of periphytic biofilm health . Finally, results were compared to studies performed before the remediation process and this did not reveal a decrease of metal accumulation in biofilms nor shifts in taxonomic composition of the communities, rather the remaining dominance of metal-resistant species such as E. minima was confirmed.
(Science of the Total Environment. vol. 425, n° 0048-9697, pp. 242-253, 13/04/2026)
UR REBX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Barred-beach morphological control on infragravity motion
A conceptual analysis of the coupling between bars and infragravity waves is performed combining laboratory experiments and numerical modeling. Experiments are carried out in a wave flume with a barred profile. The Boussinesq fully-nonlinear model SERR1D is validated with the laboratory data and a sensitivity analysis is performed next to study the influence on the infragravity wave dynamics of bar amplitude and location, and swash zone slope. A novel technique of incident and reflected motions separation that conserves temporal characteristics is applied. We observe that changing bar characteristics induces substantial variations in trapped energy. Interestingly, a modification of swash zone slope has a large influence on the reflected component, controlling amplitude and phase time-lag, and consequently on the resonant pattern. Variations of trapped infragravity energy induced by changes of swash zone slope reach 25 %. These changes in infragravity pattern consequently affect short-wave dynamics by modifying the breakpoint location and the breaking intensity. Our conceptual investigation suggests the existence of a morphological feedback through the action of evolving morphology on infragravity structures which modulates the action of short-waves on the morphology itself.
(pp. currents.24, 13/04/2026)
LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, PUC, UTFSM, LEGI, UJF, Grenoble INP, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Seasonal succession of estuarine fish, shrimps, macrozoobenthos and plankton: physico-chemical and trophic influence. The ironde estuary as a case study
Characterization of the structure and seasonal variability of biotic communities is essential for a better understanding of estuarine ecosystem functioning and in order to manage these highly fluctuant and naturally stressed systems. Numerous studies have investigated the role of environmental factors in controlling temporal variations in biotic communities. However, most have concluded that the explanatory power of physico-chemical variables was significant but not sufficient to explain ecological dynamics. The aim of the present study was to put forward the importance of trophic interactions as an additional structuring factor of species seasonal variability by examining simultaneous dynamics of all estuarine biotic communities, with the example of the oligo-mesohaline area of the Gironde estuary (SW France) as a case study. Data on the main biological groups (fish, shrimps, macrozoobenthos and plankton) sampled during a five-year period (2004-2008) at monthly intervals using a well standardized protocol, as well as data on environmental variables, were compiled here for the first time. According to species composition, results indicated that the Gironde estuary is used as a nursery, feeding, resident and migratory habitat. Results showed that, for almost all species, strong seasonal fluctuations occurred with a succession of species, indicating an optimization of the use of the available resources over a typical year by estuarine biological communities. Multivariate analyses discriminated four seasonal groups of species with two distinctive ecological seasons. A clear shift in July indicated a biomass transfer from a “planktonic phase” to a “bentho-demersal phase”, corresponding to spring and summer-autumn periods, respectively. In regard to the temporal fluctuations of dominant species of all biological groups, this study highlighted the possible influence of trophic relationships, predation in particular, on seasonal variations in species abundance, in addition to the physico-chemical influence. This study enabled us to synthesize crucial seasonal data and to discuss their integration into seasonal models of estuarine functioning and/or specific prey-predator models. In a global change context, prey abundance variations could generate changes in the temporal dynamics of their predators (and conversely), and potentially in the functioning of the whole estuarine system.
(Estuarine, Coastal and Shelf Science. vol. 112, n° 0272-7714, pp. 243-254, 13/04/2026)
UR EPBX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Vegetation dynamics in the Northeastern Mediterranean region during the past 23 000 yr: insights from a new pollen record from the Sea of Marmara
Abstract. High-resolution pollen analysis of core MD01-2430 from the Sea of Marmara (40°47.81' N, 27°43.51' E) allows us to reconstruct the vegetation response to climatic changes during the past 23 cal ka in the Northeastern Mediterranean. Variation in mesic/temperate forest cover indicates major climatic shifts connected to Heinrich Stadial 1, Bölling-Allerød, Younger Dryas and to the onset of the Holocene. Pollen–anthropogenic indicator approach was used to recognize human-induced landscape changes in the Sea of Marmara. The pollen-inferred onset of the Holocene occurs at ca. 11.5 cal ka, indicating that the Northeastern Mediterranean region represents a transitional zone where higher moisture availability supported an earlier forest expansion than the borderlands of the Aegean Sea and Black Sea. Two major forest retreats occurred during the Holocene at ca. 5.5 and 2.1 cal ka. The Holocene forest setbacks are in phase with previously published alkenone-inferred sea-surface temperature decreases in the Sea of Marmara reconstructed from the same core. Our new pollen record testifies the sensitivity of Mediterranean forests to changes in moisture availability, which is driven by changes in high-latitude atmospheric processes (North Atlantic Oscillations and/or Siberian High).
(Climate of the Past. vol. 8, n° 1814-9324, pp. 1941-1956, 13/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR ISEM, Cirad, EPHE, PSL, UM, CNRS