Chapter 4 - Introduction to the Last Deglaciation climate
This chapter briefly describes the long-term climate evolution, as well as, the superimposed abrupt climate shifts that have punctuated the Last Deglaciation, that is, the pre-Heinrich Stadial 1 and the Heinrich Stadial 1, the Bølling–Allerød Interstadial and the Younger Dryas Stadial. A short description of the impact of these abrupt changes in the North Atlantic, Greenland and Europe is also provided as a prelude to the following chapters.
(pp. 33-36, 01/01/2023)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Chapter 7 - The Younger Dryas Stadial
The Younger Dryas (YD) stadial is the last extreme cold event detected in the northern hemisphere during the last deglaciation. Many theories have been proposed to explain the causes of this event. Currently, the most accepted one is that the increased meltwater discharges into the North Atlantic or Arctic Sea produced a series of changes in ocean circulation and sea ice cover that triggered substantial shifts in the atmospheric circulation patterns. The impact of these changes is marked by a series of climate shifts within the YD stadial with a complex spatial distribution of hydroclimate in Europe in each phase.
(pp. 51-57, 01/01/2023)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Trajectories of nutrients concentrations and ratios in the French coastal ecosystems: 20 years of changes in relation with large-scale and local drivers
used to determine ecosystem trajectories as well as typologies of ecosystem trajectories. It appeared that most of the French coastal ecosystems exhibited trajectories towards a decrease in nutrients concentrations. Differences in trajectories mainly depended on continental and human influences, as well as on climatic regimes. One single ecosystem exhibited very different trajectories, the Arcachon Bay with an increase in nutrients concentrations. Ecosystem trajectories based on ordination techniques were proven to be useful tools to monitor ecosystem changes. This study highlighted the importance of local environments and the need to couple uni-and multi-ecosystem studies. Although the studied ecosystems were influenced by both local and large-scale climate, by anthropogenic activities loads, and that their trajectories were mostly similar based on their continental influence, non-negligible variations resulted from their internal functioning.
(Science of the Total Environment. vol. 857, n° 0048-9697, pp. 159619, 01/01/2023)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, AD2M, SU, CNRS, SBR, SU, CNRS, LOMIC, INSU - CNRS, SU, CNRS, OOB, SU, CNRS
New Southern Ocean transfer function for subsurface temperature prediction using radiolarian assemblages
(Marine Micropaleontology. vol. 178, n° 0377-8398, pp. 102198, 01/01/2023)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Seasonal, Diurnal, and Tidal Variations of Dissolved Inorganic Carbon and pCO2 in Surface Waters of a Temperate Coastal Lagoon (Arcachon, SW France)
We report on diurnal, tidal, and seasonal variations of dissolved inorganic carbon (DIC), water partial pressure of CO2 (pCO2), and associated water–air CO2 fluxes in a tidal creek of a temperate coastal lagoon with 70% of intertidal flats, during eight tidal/diurnal cycles and two consecutive years covering all seasons. Surface waters of the lagoon were always slightly oversaturated in CO2 with respect to the atmosphere with an average pCO2 value of 496 ± 36 ppmv. Seasonally, subsurface water pCO2 values were controlled by both temperature and biological/tidal advection effects that compensated each other and resulted in weak annual variations. High-resolution temporal pCO2 records reveal that the highest fluctuations (192 ppmv) occurred at the tidal/diurnal scale as a result of biological activity, advection from the tidal flat, and porewater pumping that all contributed to water pCO2 and carbonate chemistry variations. Total alkalinity (TA) versus salinity plots suggest a net production of alkalinity in the lagoon attributed to benthic carbonate dissolution and/or anaerobic degradation of organic matter. We specifically highlighted that for the same salinity range, during flooding, daytime pCO2 were generally lower than nighttime pCO2 values because of photosynthesis, whereas during ebbing, daytime pCO2 were higher than nighttime pCO2 values because of heating. Waters in the lagoon were a relatively weak CO2 source to the atmosphere over the year compared to other estuarine and lagoon waters elsewhere, and to sediment-air fluxes measured simultaneously by atmospheric Eddy Covariance (EC) in the Arcachon lagoon. Because of low values and small variations of the air-sea pCO2 gradient, the variability of fluxes calculated using the piston velocity parameterization was greatly controlled by the wind speed at the diurnal and, to a lesser extent, seasonal time scales. During the emersion, the comparison of these pCO2 data in the tidal creek with EC fluxes measured 1.8 km away on the tidal flat suggests high heterogeneity in air-sea CO2 fluxes, both spatially and at short time scales according to the inundation cycle and the wind speed. In addition to tidal pumping when the flat becomes emerged, our data suggest that lateral water movement during the emersion of the flat generates strong spatial heterogeneity in water–air CO2 flux.
(Estuaries and Coasts. vol. 46, n° 1559-2723, pp. 128-148, 01/01/2023)
LERPC, COAST, IFREMER, MARE, ULiège, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IFREMER, LPG, UM, UA, INSU - CNRS, CNRS, Nantes univ - UFR ST, Nantes Univ, BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA
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