Impact of Holocene coastal changes on past human communities : results from an interdisciplinary approach in the Gironde estuary mouth (North-Médoc, SW France
(06/09/2022)
UBM, CNRS, PRODIG (UMR_8586 / UMR_D_215 / UM_115), UP1, IRD, SU, CNRS, UPCité, LETG - Brest, UBO EPE, UR2, CNRS, LETG, UBO EPE, UR2, CNRS, Nantes Univ - IGARUN, LASCARBX, UB, UBM, PRODIG, UP1, IRD, EPHE, PSL, UP4, UPD7, CNRS, PRODIG (UMR_8586 / UMR_D_215 / UM_115), UP1, IRD, UPD7, SU, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UBO EPE
Sorption of benzo(a)pyrene and of a complex mixture of petrogenic polycyclic aromatic hydrocarbons onto polystyrene microplastics
Microplastics (MPs) largely occur in aquatic ecosystems due to degradation of larger plastics or release from MP-containing products. Due to the hydrophobic nature and large specific surface of MPs, other contaminants, such as polycyclic aromatic hydrocarbons (PAHs), can potentially sorb onto MPs. Several studies have addressed the potential impact of MPs as vectors of PAHs for aquatic organisms. Therefore the role of MPs as sorbents of these compounds should be carefully investigated. The present study aimed to determine the sorption capacity of benzo(a)pyrene (B(a)P), as a model pyrolytic PAH, to polystyrene (PS) MPs of different sizes (4.5 and 0.5 μm). In addition, the sorption of PAHs present in the water accommodated fraction (WAF) of a naphthenic North Sea crude oil to 4.5 μm MPs was also studied as a model of a complex mixture of petrogenic PAHs that could appear in oil-polluted environments. The results indicated that 0.5 μm MPs showed higher maximum sorption capacity (Q max ) for B(a)P (145–242.89 μg/g) than 4.5 μm MPs (30.50–67.65 μg/g). From the WAF mixture, naphthalene was sorbed at a higher extent than the other PAHs to 4.5 μm MPs but with weak binding interactions (K f = 69.25 L/g; 1/n = 0.46) according to the analysis of the aqueous phase, whereas phenanthrene showed stronger binding interactions (K f = 0.24 L/g; 1/n = 0.98) based on the analysis of the solid phase. Sorption of PAHs of the complex WAF mixture to 4.5 μm MPs was relatively limited and driven by the hydrophobicity and initial concentration of each PAH. Overall, the results indicate that sorption estimations based solely on the analysis of the aqueous phase could overestimate the capacity of MPs to carry PAHs. Therefore, controlled laboratory assays assessing the “Trojan Horse effect” of MPs for aquatic organisms should consider these findings in order to design accurate and relevant experimental procedures.
(Frontiers in Environmental Chemistry. vol. 3, 02/09/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UPV / EHU
Environmental microplastics disrupt swimming activity in acute exposure in Danio rerio larvae and reduce growth and reproduction success in chronic exposure in D. rerio and Oryzias melastigma
Microplastics (MPs), widely present in aquatic ecosystems, can be ingested by numerous organisms, but their toxicity remains poorly understood. Toxicity of environmental MPs from 2 beaches located on the Guadeloupe archipelago, Marie Galante (MG) and Petit-Bourg (PB) located near the North Atlantic gyre, was evaluated. A first experiment consisted in exposing early life stages of zebrafish (Danio rerio) to MPs at 1 or 10 mg/L. The exposure of early life stages to particles in water induced no toxic effects except a decrease in larval swimming activity for both MPs exposures (MG or PB). Then, a second experiment was performed as a chronic feeding exposure over 4 months, using a freshwater fish species, zebrafish, and a marine fish species, marine medaka (Oryzias melastigma). Fish were fed with food supplemented with environmentally relevant concentrations (1% wet weight of MPs in food) of environmental MPs from both sites. Chronic feeding exposure led to growth alterations in both species exposed to either MG or PB MPs but were more pronounced in marine medaka. Ethoxyresorufin-O-deethylase (EROD) and acetylcholinesterase (AChE) activities were only altered for marine medaka. Reproductive outputs were modified following PB exposure with a 70 and 42% decrease for zebrafish and marine medaka, respectively. Offspring of both species (F1 generation) were reared to evaluate toxicity following parental exposure on unexposed larvae. For zebrafish offspring, it revealed premature mortality after parental MG exposure and parental PB exposure produced behavioural disruptions with hyperactivity of F1 unexposed larvae. This was not observed in marine medaka offspring. This study highlights the ecotoxicological consequences of short and long-term exposures to environmental microplastics relevant to coastal marine areas, which represent essential habitats for a wide range of aquatic organisms.
(Environmental Pollution. vol. 308, n° 0269-7491, pp. 119721, 01/09/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, INRAE, UMR MARBEC PALAVAS, UMR MARBEC, IRD, IFREMER, CNRS, UM
Did eustatic sea-level control deep-water systems at Milankovitch and timescales?: An answer from Quaternary Pearl River margin
As one of the most important forcing factors, sea level fluctuations exert a major influence on deep-water depositional processes, however, it is still not well understood how they control the evolution of the specific deep-water system over different timescales. For relatively longer (1 My) and shorter (100 Ky) timescales, we characterize deep-water sedimentary records on the Pearl River margin using seismic and borehole data, and then compare them with the contemporaneous sea-level curve to exam the varied roles sea levels have played in impacting the development of the deep-marine system. Results indicate that over both the 1 My-scale and the 100 Ky-scale, the studied deep-water system shows systematic variations that are strongly suggested to arise from the modulation of sea levels. Specifically, over the 1 My-scale, facies and depocenters of the deep-water system all show significant changes. Large fan lobes (consisting of both turbidites and mass-transport deposits) with more distal depocenters likely correspond with low-amplitude and high-frequency sea level fluctuations and slightly rising shelf edge trajectories, whereas smaller turbidite fan lobes with more proximal depocenters likely reflect high-amplitude and low-frequency sea level fluctuations and steeply rising shelf-edge trajectories. In contrast, within the 100 Ky-scale of a glacial-interglacial cycle, the composition of deep-water deposits also shows significant variations. Coarser-grained deposits with higher organic carbon (TOC) content and lower calcium carbonate (CaCO3) content are interpreted to reflect periods of glacial sea-level lowstand, whereas finer-grained sediments having lower TOC and higher CaCO3 content reflect interglacial sea-level highstand. Moreover, the spectrum characteristics of these constituent curves are very similar to those of contemporaneous sea levels, reflecting Milankovitch climatic forcings and further validating the tight coupling between sea-level stands and sediment compositions. These correlations between sedimentary records and sea level behaviors suggest that it was mainly a long-term change in the amplitude and frequency of eustatic cycles that controlled the overall architecture of the deep-water system, whereas it was shorter term, changing sea-level stands that played a role and impacted the deep-water sediment composition.
(Sedimentary Geology. vol. 439, n° 0037-0738, 01/09/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Phenolic fingerprints of the Pacific seagrass Phyllospadix torreyi - Structural characterization and quantification of undescribed flavonoid sulfates
Four undescribed flavonoid sulfates were isolated from Phyllospadix torreyi S. Watson foliar tissue. In addition, nine known flavonoid sulfates and three phenolic acids were isolated from the same extract, of which seven had never been reported for the genus Phyllospadix. Structural elucidation of individual phenolics was assigned using complementary informations from their spectral evidence (HPLC-DAD, LC-MS, NMR, and UV) and chemical behavior. The inter-annual variation in phenolic concentrations was determined by quantitative HPLC-DAD over a three-year period. The results showed a relative constancy of phenolic content over time and the high prevalence of flavonoid disulfates (70–90% of the total flavonoids detected). All samples were found dominated by the unreported nepetin 7, 3′-disulfate and 5-methoxyluteolin 7, 3′-disulfate, followed by luteolin 7, 3′-disulfate. Considering the economic potential of flavonoid sulfates in the pharmaceutical and nutraceutical segments, a sample of detrital leaves was also analyzed. The same phenolic pattern was found and the concentration of the individuals, although lower than in fresh material, makes this abundant biomass of interest for dietary and pharmaceutical applications.
(Phytochemistry. vol. 201, n° 0031-9422, 01/09/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Vers une vision multipression explicative des niveaux de contamination biodisponible et de toxicité des cours d'eau.
(01/09/2022)
RiverLy, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR REVERSAAL, INRAE, UR EABX, INRAE
Wave-Current Impact on Shear Stress Patterns around 3D Shallow Bedforms
Observations from wave basin experiments and wave-resolving numerical simulations demonstrate the effect of wave-current interaction on shear stress around a sandy mound. Observations from the wave basin show that the mound deformation rate and morphological patterns depend on the mixture of waves and currents in the incident flow conditions. A SWASH nonhydrostatic numerical model was used to expand the parameter space of wave-current conditions observed in the flume and characterize the response of the near-bed shear stress to the mound. The model was validated with observations from wave-alone, current-alone, and wave-current flume tests and then ran for a suite of numerical flow conditions which isolate the impact of the ratio of wave-current energy on the bed shear stress. Results show how the current-to-wave ratio impacts the spatial heterogeneity of shear stress across the mound, with the region of shear stress intensification around the mound and the location of the peak shear stress becoming asymmetric with more mixed wave-current flows. These results show the nonlinear response of shear stress patterns to combined wave-current flows and how these patterns may impact eventual sediment transport and mound evolution.
(Journal of Marine Science and Engineering. vol. 10, n° 2077-1312, pp. 1178, 01/09/2022)
TU Delft, OSU, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Global carbon isotopic events in a Campanian–Maastrichtian deltaic succession (Tremp-Graus Basin, Spain) and multiproxy stratigraphy for high sedimentation rate environments
The Campanian to Maastrichtian sedimentary succession of the Tremp-Graus Basin (NE Spain) is characterized by the offshore-to-prodeltaic upper Vallcarga Fm giving way to prograding deltaic units (the Aren Fm), which are overlain by transitional facies (the Grey Unit) that correspond to the basal part of the Tremp Group. This work aims to improve the stratigraphical scheme of these deposits using a new dataset of δ13Ccarb and δ13Corg, δ18O and TOC variations through time, supported by a new biostratigraphical analysis and compiling previous biostratigraphical and paleomagnetic data. The comparison of isotopic signals from marine reference sections where δ13Ccarb is well calibrated in the Tethys realm allows recognition of global isotopic events that can be used as correlative marker events. Significant high-frequency δ13C variations defined in the δ13Ccarb are identified in the studied succession despite the different sedimentary setting and some can be related to global geochemical events such as the Late Campanian Event (LCE) and the Campanian–Maastrichtian Boundary Event (CMBE), in good agreement with the magnetic chrons at the base of the Tremp Group, and with some new biostratigraphic constraints. From multiple geochemical and petrographic analysis of the organic matter we suggest that the geochemical signal corresponds to global changes, but at higher resolution, sedimentary dynamics are also reflected in the geochemical signals, particularly inputs of surface water in the deltaic signal.
(Cretaceous Research. vol. 137, n° 0195-6671, pp. 105222, 01/09/2022)
Bordeaux INP, UBM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CR2P, MNHN, SU, CNRS, iSTeP, INSU - CNRS, SU, CNRS, ITES, ENGEES, UNISTRA, INSU - CNRS, CNRS, EOST, UNISTRA, INSU - CNRS, CNRS
Aluminium in aquatic environments: abundance and ecotoxicological impacts
Aluminium (Al) is a common chemical element released into the aquatic environment from the Earth’s crust and many anthropogenic activities. It may be present in various dissolved and precipitated forms [Al3+, AlOH2+, Al(OH)2+, Al(OH)03, Al(OH)4−, etc.], which are potentially toxic for organisms. This review summarizes information about the concentrations of Al detected in aquatic ecosystems and its effects on both freshwater and marine organisms (such as growth disturbance, reproduction, and respiration alterations). As the chemistry of Al is different in freshwater and marine systems, we discuss the behaviour of aluminium and its effects on marine or freshwater fauna. Therefore, the solubility of Al, as other metals, is highly pH dependent, which increases when pH decreases. We are assuming that ocean acidification, linked to climate change, would affect the Al bioavailability in the aquatic environment, which may increase its ecotoxicological effects on semi-closed (Bays, Mediterranean Sea, etc.) or closed (lakes, etc.) aquatic ecosystems.
(Aquatic Ecology. vol. 56, n° 1386-2588, pp. 751-773, 01/09/2022)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, BiOSSE, UM, IMMM, UM, INC-CNRS, CNRS
Wave runup on composite beaches and dynamic cobble berm revetments
The effects of climate change and sea level rise, combined with overpopulation are leading to ever-increasing stress on coastal regions throughout the world. As a result, there is increased interest in sustainable and adaptable methods of coastal protection. Dynamic cobble berm revetments consist of a gravel berm installed close to the high tide shoreline on a sand beach and are designed to mimic naturally occurring composite beaches (dissipative sandy beaches with a gravel berm around the high tide shoreline). Existing approaches to predict wave runup on sand or pure gravel beaches have very poor skill for composite beaches and this restricts the ability of coastal engineers to assess flood risks at existing sites or design new protection structures. This paper presents high-resolution measurements of wave runup from five field and large-scale laboratory experiments investigating composite beaches and dynamic cobble berm revetments. These data demonstrated that as the swash zone transitions from the fronting sand beach to the gravel berm, the short-wave component of significant swash height rapidly increases and can dominate over the infragravity component. When the berm toe is submerged at high tide, it was found that wave runup is strongly controlled by the water depth at the toe of the gravel berm. This is due to the decoupling of the significant wave height at the berm toe from the offshore wave conditions due to the dissipative nature of the fronting sand beach. This insight, combined with new methods to predict wave setup and infragravity wave dissipation on composite beaches is used to develop the first composite beach/dynamic revetment-specific methodologies for predicting wave runup.
(Coastal Engineering. vol. 176, n° 0378-3839, pp. 104148, 01/09/2022)
BRGM, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UFRN, UC