Energy and dissipation spectra of waves propagating in the inner surf zone
The spectral behavior of random sawtooth waves propagating in the inner surf zone is investigated in this study. We show that the elevation energy spectrum exhibit a universal shape with a ω −2 tendency in the inertial subrange and an exponential decay in the diffusive subrange (ω being the angular frequency). A theoretical spectrum is derived based on the similarities between sawtooth waves in the inner surf zone and Burgers wave solutions. A very good agreement is shown between this theoretical spectrum and laboratory experiments covering a large range of incident random wave conditions. Additionally an equation describing the universal shape of the dissipation spectrum is derived. It highlights that the dissipation spectrum is nearly constant in the inertial subrange, consistent with prior laboratory observations. The findings presented in this study can be useful to improve broken wave dissipation parametrizations in stochastic spectral wave models.
(Journal of Fluid Mechanics. vol. 977, n° 0022-1120, pp. A48, 11/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Evaluating pesticide mixture risks in French Mediterranean coastal lagoons waters
To assess the risk of pesticide mixtures in lagoon waters, this study adopted a multi-step approach using integrative passive samplers (POCIS) and concentration addition (CA) toxicological models. Two French Mediterranean lagoons (Thau and Or) were monitored for a range of 68 pesticides continuously over a period of a year (2015–16). The findings revealed mixtures of dissolved pesticides with varying composition and levels over the year. The Or site contained more pesticides than Thau site (37 vs 28 different substances), at higher concentrations (0.1–58.6 ng.L−1 at Or vs \textless0.1–9.9 at Thau) and with overall higher detection frequencies. All samples showed a potential chronic toxicity risk, depending on the composition and concentrations of co-occurring pesticides. In 74 % of the samples, this pesticide risk was driven by a few single substances (ametryn, atrazine, azoxystrobin, carbendazim, chlorotoluron, irgarol, diuron and metolachlor) and certain transformation products (e.g. DPMU and metolachlor OA/ESA). Individually, these were a threat for the three taxa studied (phytoplankton, crustaceans and fish). Yet even a drastic reduction of these drivers alone (up to 5 % of their current concentration) would not eliminate the toxicity risks in 56 % of the Or Lagoon samples, due to pesticide mixtures. The two CA-based approaches used to assess the combined effect of these mixtures, determined chronic potential negative impacts for both lagoons, while no acute risk was highlighted. This risk was seasonal, indicating the importance of monitoring in key periods (summer, winter and spring) to get a more realistic picture of the pesticide threat in lagoon waters. These findings suggest that it is crucial to review the current EU Water Framework Directive's risk-assessment method, as it may incorrectly determine pesticide risk in lagoons.
(Science of the Total Environment. vol. 867, n° 0048-9697, pp. 161303, 11/04/2026)
UMR MARBEC, IRD, IFREMER, CNRS, UM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UB
Characterization of the bioaccumulation and toxicity of copper pyrithione, an antifouling compound, on juveniles of rainbow trout
Since the global ban on tributyltin in antifouling paints in 2008 by the International Maritime Organization, new products have been developed and brought to the market. Among them, copper pyrithione (CuPT) is used, but its mechanisms of toxicity remain little known. This project aimed to identify and measure the impacts of aqueous exposure to CuPT, an organic compound, and compare it to ionic Cu ²⁺ added in the form of its inorganic salt CuSO 4 , in equivalent Cu ²⁺ molar concentrations, on rainbow trout ( Oncorhynchus mykiss ) juveniles under controlled laboratory conditions. A 24-hour acute exposure was performed with nominal concentrations of 50 and 100 µg/L Cu from either CuSO 4 or CuPT (labelled CuSO 4 _50, CuSO 4 _100, CuPT_50 and CuPT_100, respectively). The CuPT_100 condition induced 85 % mortality in 15 hours and the CuPT_50 condition induced 5 % mortality in the same period. A chronic exposure was then performed with nominal concentrations of 1 and 10 µg/L Cu from CuPT and 10 µg/L Cu ²⁺ from CuSO 4 (labelled CuSO 4 _1, CuSO 4 _10, CuPT_1 and CuPT_10, respectively). Measured aqueous concentrations of Cu ²⁺ were slightly higher than nominal concentrations for the lower concentrations, but lower for the CuPT_10 condition. The 8- and 16-day toxicokinetics showed a greater accumulation of copper in the gills of fish exposed to CuPT compared to fish exposed to Cu ²⁺ from CuSO 4 . The CuPT_10 condition induced 35 and 38 % mortality after 8 and 16 days of exposure, while no mortality was observed in the CuSO 4 _10 condition. The growth of juveniles was not impacted during the 16 days of exposure for any condition. The activity of antioxidant enzymes (CAT, SOD, GPx) did not respond to exposure to either contaminant. The expression of genes involved in the antioxidant response ( sod1 , sod2 , gpx ), detoxification ( cyp1a , mt1x , mt2x ), Cu transport ( ctr1 , ctr2 , slc11a2 ), energy metabolism ( AcoAc , cox , 12S) and cell cycle regulation ( bax ) strongly decreased at Day 8 in the gills and at Day 16 in the liver of CuPT-exposed fish in comparison to controls at the same time point. This study clearly showed that the toxicity of Cu in the form of CuPT was much higher than that of ionic Cu from CuSO 4 and provides new information on the compound that will be useful to develop regulations concerning its use and release in the aquatic environment.
(Peer Community In Ecotoxicology and Environmental Chemistry, n° 2779-9948, 11/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Study of an outcropping deltaic reservoir analog: From digital outcrops to 3D reservoir model (Roda Sandstones, Graus-Tremp Basin)
(11/04/2026)
GEOPS, INSU - CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IFPEN
Temperature and feeding frequency impact the survival, growth, and metamorphosis success of Solea solea larvae
Human-induced climate change impacts the oceans, increasing their temperature, changing their circulation and chemical properties, and affecting marine ecosystems. Like most marine species, sole has a biphasic life cycle, where one planktonic larval stage and juvenile/adult stages occur in a different ecological niche. The year-class strength, usually quantified by the end of the larvae stage, is crucial for explaining the species' recruitment. We implemented an experimental system for rearing larvae under laboratory conditions and experimentally investigated the effects of temperature and feeding frequencies on survival, development (growth), and metamorphosis success of S. solea larvae. Specific questions addressed in this work include: what are the effects of feeding regimes on larvae development? How does temperature impact larvae development? Our results highlight that survival depends on the first feeding, that the onset of metamorphosis varies according to rearing temperature and that poorly fed larvae take significantly longer to start (if they do) metamorphosing. Moreover, larvae reared at the higher temperature (a +4˚C scenario) showed a higher incidence in metamorphosis defects. We discuss the implications of our results in an ecological context, notably in terms of recruitment and settlement. Understanding the processes that regulate the abundance of wild populations is of primary importance, especially if these populations are living resources exploited by humans.
(PLoS ONE. vol. 18, n° 1932-6203, pp. pp. e0281193, 11/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR MARBEC, IRD, IFREMER, CNRS, UM
Storm response and multi-annual recovery of eight coastal dunes spread along the Atlantic coast of Europe
Coastal dunes are natural barriers against coastal flooding, and represent large sources of sediment to mitigate coastal erosion, besides being a natural habitat for many living beings. Yet, these complex environments are threatened by sea level rise and possibly enhanced storminess in the future. Most of the studies on coastal dune erosion and recovery from storms are either site specific or focus on a short-time scale, from months to a couple of years. Here, airborne LiDAR data collected from 2011 to 2020 at eight diverse coastal dunes, spread from NW England to SW France, were analysed to study their response, and recovery from the most energetic extreme storms wave conditions since at least 1948. Results show that the 2013/14 winter was the first or second largest erosive event (from −14 to −290 m3/m dune volume loss) from 2011 to 2020 at all sites. The magnitude of storm-driven sand volume loss was mainly controlled by dune face slope (r = 0.84). Dunes with steeper pre-storm slopes lost the largest volumes of sand. At a dune scale, the scarping height was also well correlated to the dune face slope at sites where storm response was characterized by limited alongshore variability. Dune recovery was site specific (no recovery, partial, complete, excess), with dunes that either progressively returned to their pre-storm morphology or were reshaped while recovering. Percentage of dune sand volume recovery was well correlated to the local and long-term satellite-derived shoreline change rate computed from 1984 to 2021 (r = 0.81), suggesting that dune recovery is mainly controlled by the local coastal sediment budget. The rate of dune crest elevation increase (from 4.2 to 12 cm/year) at four of the study sites from 2011 to 2020, largely exceeded sea level rise rate over the past decade (3.3 ± 0.7 mm/year). These results provide key insight into the contrasting resilience of some of the most exposed coastal dunes along the Atlantic coast that recover at different rates following the same sequence of extreme storms
(Geomorphology. vol. 435, n° 0169-555X, pp. 108735, 11/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Image analysis and benthic ecology: Proceedings to analyze in situ long‐term image series
Long time series of underwater images have become a tool widely used within the benthic ecology research community. The development of new acquisition systems with bigger storing capacities lead researchers and scientists to deploy them for longer periods resulting in large amounts of data. This paper focuses on the first steps of analyzing large numbers of underwater images, which involves assessing the amount of valid data while assuming no technical problems. The question here addressed is how many of the in situ images can reliably be really used for benthic ecology purposes. To answer this question, we propose a method to eliminate nonvalid images and use it with four different sets of time-lapsed images acquired for long periods ranging from 73 to 371 ds in a row. The results show that elimination of between 8% and 22% of the images is possible depending on the data set. The main advantage of the method is easing and accelerating automation of subsequent analysis.
(Limnology and Oceanography: Methods. vol. 21, n° 1541-5856, pp. 169-177, 11/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IO-PAN, PAN
Holocene hydroclimate variability along the Southern Patagonian margin (Chile) reconstructed from Cueva Chica speleothems
Patagonia is ideally situated to reconstruct past migrations of the southern westerly winds (SWWs) due to itssoutherly maritime location. The SWWs are an important driver of Southern Ocean upwelling and their strengthand latitudinal position changed during the Holocene, leading thus to different responses of the vegetation topast climate changes along the Chilean continental margin. A new speleothem record from Cueva Chica (51◦S) isinvestigated to reconstruct past climatic changes throughout the Holocene in conjunction with other marine andpaleoenvironmental records of the region and better constrain the regional paleoclimatic evolutions of SWWs.Samples comprising both a flowstone core and a stalagmite were radiometrically dated (U–Th & 14C) toconstruct age-depth models for the highly-resolved proxy profiles (δ13C, δ18O, chemical composition). TheCueva Chica record provides a highly-resolved isotopic and elemental curves for the last 12 ka, albeit with ahiatus from 5.8 to 4 ka BP. The multi-proxy analysis suggests three climatic regimes throughout the Holocene inSouthern Patagonia: i) an early Holocene wet period (with the exception of two dry excursions at 10.5 ka and 8.5ka BP), ii) a mid-Holocene dry period and iii), a return to generally wet conditions over the late Holocene. Theglobal drivers for these tri-phased climatic regimes are likely related to oceanic and South polar feedbacks. Theearly Holocene was the warmest period and might be attributable to changes in global ocean circulation whichinvolved a rise in air T◦ and a strength in SWW from 50◦S, and therefore higher precipitations over landmass.After 9 ka BP, an intensified deglaciation dynamic along the Antarctic Peninsula is concordant with increasingsummer insolation in the Southern hemisphere, leading to a poleward shift of the SWWs in response to globalwarming and thus to a reduction in moisture supply from the Pacific onto the Patagonian shore. After 5 ka BP, agradual SST decline is consistent with an equatorward shift of the SWWs in response to a cooling Southernhemisphere. The SWW storm tracks extended to lower latitudes, inducing a return to wetter conditions withhighly variable moisture patterns along the Patagonian landmass. Clumped isotope (Δ 47) analyses at lowerresolution reflect the degree of kinetic isotope fractionation at the time of carbonate deposition, especially duringthe dry interval around 8.5–5.5 ka BP. Reduced kinetic isotope fractionation is observed since at least 2.6 ka BP,a period marked by (slightly) wetter conditions.
(Global and Planetary Change. vol. 222, n° 0921-8181, pp. 104050, 11/04/2026)
IDEES, UNICAEN, NU, ULH, NU, UNIROUEN, NU, CNRS, IRIHS, UNIROUEN, NU, VUB, EDYTEM, USMB [Université de Savoie] [Université de Chambéry], CNRS, Fédération OSUG, VUB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, MPIC, GFZ, UBA, UMAG
Morphodynamics of wave-dominated beaches
Abstract Wave-dominated sandy beaches are highly valued by societies and are amongst the world’s most energetic and dynamic environments. On wave-dominated beaches with unlimited sand supply and limited influence of tide and geology, beach change has long been conceptualised in the morphodynamic framework of Wright and Short (1984). Such framework describes the occurrence of beach types based on wave conditions and sediment characteristics across the complete reflective–dissipative spectrum. Building on theoretical work, field/laboratory measurements and monitoring programmes, the physical mechanisms underpinning this morphodynamic framework have been progressively unravelled. Cross-shore morphological changes are primarily controlled by equilibrium and beach memory principles with below (above) average wave conditions driving down-state (up-state) transitions associated with onshore (offshore) sediment transport. Such cross-shore behaviour mostly reflects the imbalance between the onshore-directed sediment transport driven by wave nonlinearities and the offshore-directed sediment transport driven by the undertow. Self-organised morphological instabilities resulting from different positive feedback mechanisms are primarily responsible for alongshore morphological variability and the generation of rhythmic morphological features, such as crescentic bars, rip channels and beach cusps. Critically, wave climate and changes in wave regimes are key in driving the coupled cross-shore and longshore behaviour that ultimately explains modal beach state and frequency-response characteristics of beach morphological time series.
(Cambridge Prisms: Coastal Futures. vol. 1, pp. e1, 11/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Settling dynamics of cohesive sediments in a highly turbid tidal river
An optical settling column was used in the Garonne Tidal River to estimate the settling velocity of suspended matter in surface waters over a period characterized by contrasting hydrological conditions. A time and space variability of settling velocity was observed during this study. The settling velocities of surface suspended matter ranged from 0.018 to 0.268 mm.s −1 , and the median diameter of dispersed particles varied from 4.74 to 14.38 µm. The data revealed the physical processes influencing the sediment settling dynamics throughout different time scales in a highly turbid tidal river. On tidal and fortnightly time scales, resuspension, deposition and advection mechanisms were the major drivers of the settling velocity variability, while it is likely that the estuarine turbidity maxima (ETM) was responsible for seasonal variations. The findings of this work suggest that in tidal rivers, salinity is too low to promote flocculation, whereas ETM can play a key role in enhancing this process. The stronger variability in settling velocity occurs on a tidal timescale, with median values up to four times higher at the end of the ebb tide than at high water. These variations cannot be correlated to salinity or sediment concentration. On a seasonal timescale, flocculation appears to be strongly correlated with the presence of the ETM and associated fluid mud layer. A simple correlation based on tidal variations seems to be a better predictor than the relationships based on the sediment concentration.
(Marine Geology. vol. 457, n° 0025-3227, pp. 106995, 11/04/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IGE, IRD, INSU - CNRS, CNRS, INRAE, Fédération OSUG, UGA, Grenoble INP, UGA