Long-term impact of dredging and beach nourishment works on benthic communities
Dredging and rainbowing techniques are commonly used to replenish sandy beaches and protect the coast against erosion. Since 2003, such operations have been conducted every other year on Pyla Beach, Arcachon Bay (French Atlantic Coast). The evolution of macrobenthic communities subjected to regular disturbance was analyzed once in springtime at dredging and disposal sites, as well as in a control area, over 21 years. The overall benthic community was dominated by the same few species. The dredged area harbors a benthic community whose characteristics suggest the maintenance of a disturbed status, compared to the control area, whose community follows a trajectory possibly influenced by the general decrease of organic matter in the sediment. Regarding the disposal site, species richness is slowly declining. In both disturbed areas, the community was dominated by species able to recolonize rapidly (polychaetes, peracarid crustaceans), while the control area rather favored bivalves.
(Estuarine, Coastal and Shelf Science. vol. 313, n° 0272-7714, pp. 109119, 01/02/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Is reducing phosphorus inputs sufficient to reduce hypoxia in estuaries? The example of the Loire estuary
Coastal deoxygenation is mainly attributed to excessive nutrient and organic matter inputs from anthropogenic activities. However, although mitigation strategies have been implemented to reduce nutrient inputs, the recovery of estuarine systems has often been limited. By examining long-term data from the turbid Loire estuary, which is prone to summer hypoxia, we aimed to understand the influence of these initiatives on nutrient and dissolved oxygen levels. The data showed that despite the reduction of dissolved phosphorus in the inner estuary, summer hypoxia persisted. By integrating high spatial resolution datasets, we identified nutrient sources, particularly ammonium, in the estuarine turbidity maximum zone. Nutrient recycling is likely to maintain summer hypoxia and hinder ecosystem recovery from hypoxia. A comprehensive understanding of estuarine geochemistry and internal nutrient cycling is essential to develop targeted remediation strategies and mitigate the ongoing threat of hypoxia.
(Estuarine, Coastal and Shelf Science. vol. 313, n° 0272-7714, pp. 109110, 01/02/2025)
LPG, UM, UA, INSU - CNRS, CNRS, Nantes univ - UFR ST, Nantes Univ, Bordeaux INP, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IPREM, UPPA, INC-CNRS, CNRS, LPG-ANGERS, LPG, UM, UA, INSU - CNRS, CNRS, Nantes univ - UFR ST
Distribution of organic matter and diatom frustules (diversity, flux) along the western Indian continental shelf related to contrasting physicochemical settings
The western Indian continental shelf (eastern Arabian Sea) exhibits contrasting biogeochemical features. This area becomes highly productive due to summer monsoon-driven coastal upwelling in the south and winter monsoon-induced convective mixing in the north. Additionally, in the northern self, the eastern boundary of the Oxygen Minimum Zone (OMZ) persists but is absent in the south. Phytoplankton blooms are dominated by diatoms that contribute to sedimentary phytodetritus flux supplying major elements (C, N, Si) and food for benthic biota and hence important to address. Here we present the data on organic matter content, diatom frustule flux, abundance, and diversity using surface sediments (core tops collected using a multicorer) from 6 locations (11-21° N) along the shelf in a 2° interval at 200 m isobaths. The organic matter retrieved from the core top was relatively fresh (nearly 4.5 years old) as evident from 210 Pb profiles Frustule abundance and diversity (the maximum at 15° N and minimum at 19° N) varied from 0.10-18.46 ×10 4 valves g -1 and 0.79-2.32, respectively. A total of 36 diatom genera were found with two centric (Thalassiosira and Coscinodiscus), and one pennate (Nitzschia) diatoms as major contributors. The higher contribution of Thalassiosira was observed throughout the shelf dominating the south (11, 13, 15° N), whereas, in the north (17, 19, 21° N) Coscinodiscus was dominant.
The highest organic matter content (3.4%) and frustule abundance (18.46 × 10 4 valves g -1 ) were seen at 15° N despite low diatom valve flux (3.3 × 10 3 valves cm -2 yr -1 ) and could be due to the influence of OMZ, where organic matter is well preserved. Contrarily, the upwelling-influenced station in the south (at 11° N) exhibited the highest diatom valve flux (10.14 × 10 3 valves cm -2 yr -1 ) however low organic matter content (1.6 %) and frustule abundance (4.99×10 4 valves g -1 ) was attributed to faster mineralization. This study suggested that the preservation potential of organic matter varies across the shelf and is likely to control its recycling, impacting nutrient release and resources for the benthic community.
(Marine Environmental Research. vol. 204, n° 0141-1136, pp. 106940, 01/02/2025)
NIO, AcSIR, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Source of rainfall above Mediterranean caves (Chauvet and Orgnac) and long-term trend of cave dripping oxygen isotopes based on 20 years monitoring records: Importance for speleothem-based climate reconstructions
(Quaternary Science Reviews. vol. 349, n° 0277-3791, pp. 109145, 01/02/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GLACCIOS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, GEOTRAC, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
Correction to: Main conclusions and perspectives from the collective scientific assessment of the effects of plant protection products on biodiversity and ecosystem services along the land–sea continuum in France and French overseas territories
The default Competing Interests statement has been published when in fact the following information is missing: Since 2022, Stéphane Pesce has held the position of Vice-Chairman of the evertéa Foundation, which since 2013 has been chaired by Philippe Garrigues, Editor-in-Chief of Environmental Science and Pollution Research. These Vice-Chairman and Chairmanship functions are performed on a purely voluntary basis, with no compensation of any kind. Stéphane Pesce co-authored this article as part of his role as scientific lead for the collective scientific assessment on the effects of plant protection products on biodiversity and ecosystem services along the land–sea continuum in France and French overseas territories, on which this work is based. The other authors declare no competing interests.
(Environmental Science and Pollution Research. vol. 32, n° 0944-1344, pp. 4927-4928, 31/01/2025)
RiverLy, INRAE, ECOSYS, INRAE, IFREMER, INRAE, UCA, LPED, IRD, AMU, INERIS, EMMAH, AU, INRAE, ICE, VAS, CRIOBE, UPVD, EPHE, PSL, CNRS, URCA, CNELIAS, AU, AMU, MMSH, AMU, CNRS, CNRS, UCBL, LCE, CNRS, UMLP, UBFC, UMR SAVE, UB, Bordeaux Sciences Agro, INRAE, DECOD, IFREMER, INRAE, Institut Agro, Institut Agro, OFB - DRAS, OFB, UniCA, ENSFEA, LEREPS, UT Capitole, Comue de Toulouse, UT2J, Comue de Toulouse, ENSFEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR Eco&Sols, Cirad, IRD, INRAE, Institut Agro, IODE, UR, CNRS, UPR HORTSYS, Cirad, UMR MARBEC, IRD, IFREMER, CNRS, UM, INRAE, Institut Agro, UBE, AMURE, IRD, IFREMER, UBO EPE, CNRS, UR EABX, INRAE, AU, ICRA, UdG, PHYTOX, IFREMER, URAFPA, UL, INRAE, UR HYCAR, INRAE
Impact of land cover and climate change on Aquifer Thermal and Energy Storage (ATES) system performance
This study investigates the impact of climate change and intense urbanization on Low-Temperature Aquifer Thermal Energy Storage (LT-ATES) systems. A synthetic groundwater model was developed to consider transient thermal boundary conditions due to climate change, urbanization, and evolving building thermal demands. Four scenarios were analyzed, showing potentially significant influences on subsurface thermal conditions, leading to distinct aquifer temperature profiles. The results for conditions with strong ground heat gain indicate pronounced subsurface warming and imbalanced thermal plume extensions and decreasing ATES performance over time. Recommendations include incorporating realistic surface boundary conditions in ATES modeling and strategies to mitigate adverse thermal impacts from urbanization.
(Geothermics. vol. 127, n° 0375-6505, 30/01/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR G-EAU, Cirad, BRGM, IRD, INRAE, Institut Agro, UM, MLU
Hydration of 3-Methyl-1,2,3-butanetricarboxylic Acid (MBTCA) Evidenced by Matrix-Isolation Infrared Spectroscopy
Hydration mechanism of 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), a relevant marker of secondary organic aerosol formation from the atmospheric oxidation of -pinene, has been investigating using matrix isolation infrared spectroscopy technique. The experimental results were supported by theoretical calculations. Monomers of MBTCA and heterocomplexes MBTCA-n(H2O) were identified. The presence of intramolecularly H-bonded monomers was experimentally identified in accordance with the calculations. Hetero-complexes i.e., aggregates with water, were found much more stable than homo complexes. The results clearly demonstrate the affinity of MBTCA carboxylic functions for water molecules and thus, its ability to form H-bond network leading to the solvation of the molecule. This is the first experimental observation evidencing the primary hydration stages of one relevant marker of SOA (Secondary Organic Aerosols) formation and ageing. Although fundamental, such a molecular study helps in a better understanding of critical steps in cloud condensation nuclei formation.
(Journal of Physical Chemistry A, n° 1089-5639, 24/01/2025)
PIIM, AMU, CNRS, ISM, UB, INC-CNRS, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LASIRE, INC-CNRS, CNRS
biolutoxR: An R-Shiny package for easy performing data analysis of a toxicity test based on bacterial bioluminescence inhibition
In the 21st century, in the context of an environmental crisis, chemical pollution has become a major global concern. In addition to chemical analysis, many bioassays have been developed and have proved to be interesting tools for considerably improve our understanding of the effects of human activities on species and ecosystems. Compared with animal or plant bioassays, bacterial bioassays based on bioluminescence inhibition have the advantage of being relatively economical and reproducible. This toxicity test uses the bioluminescent metabolic response of bacteria exposed for a short time to a solution of interest in the aim of assessing and quantifying its toxicity. Although routine tools are available to pre-process the data obtained, to our knowledge no flexible research tool is available for the data analysis following these tests, which could limit the access to the results for novices or experienced people unfamiliar with data processing software. To overcome this lack of tools for this bioassay, an R-Shiny package is proposed to generalise data analysis following a toxicity test based on bacterial bioluminescence inhibition. The traditional paper-based working environment is reproduced digitally in this package, which ultimately facilitates data entry and cleaning, makes the creation of relevant dynamic graphs, and simplifies access to toxicity data (e.g. dose-response curve and median effective concentration, i.e. EC 50 ). The aim of this tool is to provide the target community with a high-performance tool that can be used to obtain toxicity test results based on the inhibition of bacterial bioluminescence.
(SoftwareX. vol. 29, n° 2352-7110, 24/01/2025)
LIENSs, INSU - CNRS, ULR, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UR EABX, INRAE
A remote monitoring approach for coastal engineering projects
High costs and project-based (short-term) financing mean that coastal engineering projects are often undertaken in the absence of appropriate post-construction monitoring programmes. Consequently, the performance of shoreline-stabilizing structures or beach nourishments cannot be properly quantified. Given the high value of beaches and the increase in erosion problems and coastal engineering responses, managers require as much accurate data as possible to support efficient decision-making. This work presents a methodological approach to characterise coastline position changes as a result of engineering actions. We describe a new, low-cost method based on satellite remote sensing to monitor shoreline evolution at high temporal and spatial resolution pre-, during and post-implementation. Initially, satellite-derived waterlines are identified and extracted from publicly available satellite imagery of the Landsat 5, 7, 8, and 9, and Sentinel-2 constellations using the automatic shoreline extraction tool SHOREX. The waterline positions are then compiled, differences over time are quantified, and a matrix is constructed that allows easy depiction and interpretation of spatial and temporal patterns of erosion/accretion. This allows the access and the comprehension of the morphological data by the non-expert. Two examples of application on the Valencian coast of Spain at different spatial scales demonstrate how beach response to coastal engineering actions can be characterised at different levels of detail (from local to regional) and over different periods of time. These applications evidence the utility of the approach as it allows analysis of pre-and postintervention coastal change and offers a means to overcome the widespread lack of monitoring and hence to improve coastal engineering practice.
(Scientific Reports. vol. 15, n° 2045-2322, 23/01/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Deciphering tidal signature in a fluvial-dominated delta using digital outcrop models (Roda Sandstone, Eocene, South Pyrenean Basin)
Deltaic environments are crucial depositional systems for georesources, often studied for their excellent reservoir quality in both ancient and modern contexts. However, while mixed river tide-influenced deltas are complex and important, they remain underexplored in the ancient sedimentary record. This study focuses on the Roda Sandstone, a Lower Eocene fluvial-dominated, tide-influenced delta system in the Graus-Tremp foreland basin, to address gaps in understanding the interaction between fluvial and tidal processes within these environments. Fieldwork and core analysis were conducted to investigate the Roda Sandstone. Nineteen sedimentological sections were logged, and palaeocurrents were measured in the field. A Digital Outcrop Model (DOM) was created using 11,000 drone-captured images, georeferenced with DGPS data. The Digital Outcrop Model was processed with photogrammetry and analysed using a specialised for detailed stratigraphic and facies interpretation. Additionally, five well cores, totalling 340 m, were described and integrated with the Digital Outcrop Model. The sedimentological and stratigraphic study combined with the Digital Outcrop Model interpretation led to the identification of 10 facies grouped into five facies associations and the recognising of 7 deltaic lobes, representative of fifth-order sequences. The 3D evolution of these lobes reveals variations in progradation directions and the intensity of tidal reworking. This shows a gradual shift to a tidally dominated-deflected delta front as they were prograde. This work enabled the characterization of tidal sedimentary bodies, including the dimensions of tidal dunes and bars, paleo-bathymetries, and their specific locations within both progradational and retrogradational sequences. During regressive periods, the preservation of tidal dunes and bars intercalated in the delta foresets depends on the fluvial sediment supply and autocyclic factors. Whereas the preservation of larger tidal bars on bottomsets is permitted by the lower river sediment supply during transgressive periods of fourth-order cycles. This research advances our understanding of ancient mixed deltas by providing a depositional model that clarifies the preservation of tidal features. Additionally, it underscores the value of DOMs in enhancing correlations, distinguishing different sedimentary structures generated by competing currents, and offering detailed facies mapping for improved paleoenvironmental interpretations.
(03/01/2025)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GEOPS, INSU - CNRS, CNRS, IFPEN, IUF, M.E.N.E.S.R., LIENSs, INSU - CNRS, ULR, CNRS