Interspecific variability of fatty acid profiles of the two freshwater diatoms, Gomphonema gracile and Nitzschia palea, in comparison with classical descriptors and in response to herbicides contaminations
Many studies showed the impact of pesticides on diatom's metabolism. Diuron decreases the photosynthetic activity and synthesis of polyunsaturated fatty acid whereas s-metolachlor decreases the synthesis of long chain fatty acids. Fatty acids (FA) are essential elements for the structure of biological membranes and for the storage of metabolic energy. For example polyunsaturated fatty acids (PUFA) play a key role in membrane fluidity. Various studies demonstrated impacts of chemical contamination on fatty acid profiles. Furthermore, variability of fatty acid profiles of marine microalga in response to herbicides has been proved. However, to our knowledge scarce studies showed the interspecific variability of fatty acid profiles of freshwater diatoms especially in response to a pesticide contamination. The aims of this study were to investigate the interspecific variability of two freshwater diatoms on photosynthesis, growth rate, concentration in chlorophyll a and carotene and induction or repression of interest genes; Study this variability on fatty acid profiles; with and without pesticides. To address this issue, two model freshwater diatoms, Gomphonema gracile (GGRA) and Nitzschia palea (NPAL), were exposed separately during seven days to diuron and s-metolachlor at high concentration (C=10 µg/L) and at 20.5°C. For control condition, NPAL had a higher chlorophyll a and carotenoid concentration than GGRA. An interspecific variability of fatty acid profiles was observed with a lower percentage of saturated fatty acid (SFA) and highly unsaturated fatty acid (HUFA) for NPAL than GGRA. However, NPAL had a higher percentage of 22:6n3 than GGRA. Diuron decreased the percentage of chlorophyll a and carotenoid concentration of NPAL while no significant effect was observed for GGRA. Diuron increased percentage of SFA for NPAL whereas a decrease was noted for GGRA; the percentage of 14:0 and 16:0 increased for NPAL while it decreased for GGRA. NPAL had a different fatty acid profile compared to GGRA and seemed to have diverging mechanisms of protection in response to a contamination. This study proved the importance to taking into account interspecific variability of fatty acid profiles of diatoms for further use them as biomarkers of toxic contamination in fresh waters.
(pp. 27, 20/06/2026)
UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CNRS
Fouiller sur l'estran : des contraintes et des opportunités
Sur estran, les vestiges apparaissent très bien conservés et parfois même immédiatement apparents lors de périodes d’érosion. Mais les contraintes s’accumulent à tous les niveaux : temps d’intervention limité, présence de l’eau, alternance des marées, rapidité de l’érosion dans certains secteurs, conditions d’accès ou de fouille, difficulté de mise en place d’infrastructures lourdes. Pour ces raisons, les interventions sur cet espace sont longtemps restées limitées à de simples observations accompagnées de prélèvements. La montée en puissance des problématiques littorales et l’accélération des processus d’érosion a alors motivé la mise au point de véritables projets de prospection et de fouille. Réalisés ni dans des conditions terrestres classiques ni dans des conditions subaquatiques, ces opérations ont souvent nécessité une méthodologie originale et l’appel à de nouveaux outils ou des modalités de prélèvements particulières. Quelques exemples choisis dans des contextes variés illustrent la réactivité et les adaptations nécessaires à des sites généralement bien conservés, souvent dotés de vestiges organiques, voire de restes de poissons ou de crustacés.
(Les Nouvelles de l'archéologie, n° 0242-7702, pp. 48-52, 20/06/2026)
CReAAH, UM, UR, UR2, CNRS, UFR HHAA, UN, MC, DRAC Normandie, MCC, MC, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UP1, CNRS, Inrap, LASCARBX, UB, UBM, LETG - Brest, LETG, UNICAEN, NU, UA, EPHE, PSL, UBO EPE, UR2, CNRS, IGARUN, UN, UBM, CNRS
Spatial variability and sources of platinum in a contaminated harbor – tracing coastal urban inputs
Biogeochemical cycles that include processes to control platinum (Pt) distribution remain widely unknown in aquatic environments, especially in coastal systems. Dissolved Pt concentrations in coastal seawater (PtD) and in suspended particulate matter (SPM, PtP) were measured, together with master variables comprising dissolved oxygen, dissolved and particulate organic carbon, chlorophyll-a, turbidity, and ammonium levels, along two longitudinal profiles in the industrial Genoa Harbor (north-west Italy). Concentrations and spatial distribution of PtD and PtP levels reflect distinct concentration gradients that were attributed to different Pt sources such as hospital, domestic and industrial wastewater, atmospheric deposition, and/or road runoff. Concentrations reaching up to 0.18 ng L−1 PtD and 14 ng g−1 PtP reflect the impact of Pt urban inputs to coastal sites. These first data highlight considerable anthropogenic contamination in a confined harbor compared with the proposed reference value for the western Mediterranean surface seawater measured at external sites. Identified correlations between Pt levels and human pollution signals suggest the potential use of Pt as a new tracer of anthropogenic inputs that can be applied to other urbanised coastal systems. Biogeochemical processes that induce changes in the partitioning and fate of Pt in coastal seawater reflect a spatial variability and highlight the need for comprehensive environmental monitoring at an appropriate spatial scale.
(Environmental Chemistry. vol. 17, n° 1448-2517, pp. 105-117, 20/06/2026)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UNIGE, UniGe
Editorial for the Special Issue "Remote Sensing in Coastal Zone Monitoring and Management-How Can Remote Sensing Challenge the Broad Spectrum of Temporal and Spatial Scales in Coastal Zone Dynamic?
Coastal zones are sensitive areas responding at various scales (events to long-term trends) where the monitoring and management of physico-chemical, biological, morphological processes, and fluxes are highly challenging. They are directly affected by anthropization (urbanization, industrialization, agri-and aquaculture) and climate change (e.g., river discharges, waves, sea-level rise). Coastal waters only represent 15% of the global ocean, but concentrate 90% of commercial fisheries, contribute to 25% of global biological productivity, and represent 80% of the marine biodiversity, while being associated with an intensive tourism-related economy. The monitoring and management of coastal zones require past, present, and future observations adapted to quite diverse and dynamic environments. To complement field measurements, the use of remote sensing data provides useful information to map the hydromorphological (freshwater discharge, currents, shoreline evolution), physico-chemical (water transparency, temperature, salinity, oxygen, nutrients, and pollutants), and biological (habitats, phytoplankton blooms) properties of the coastal zones. This special issue highlights how the monitoring of coastal zones benefits from both long-term (~40 years) and recent capabilities of remote sensing observations. It also provides new methodologies to optimize the combined use of multi-mission satellite/airborne data and field measurements for an integrated approach. Considering different types of coastal environments (bays, estuaries, sandy and muddy systems), several key land and water quality (vegetation, temperature, concentrations of suspended particulate matter and polychlorinated biphenyl, aquatic plants) and morphological (shorelines, mudbanks, wetlands) parameters can be remotely sensed at various spatial and temporal scales, using innovative methods and providing validated products.
(Remote Sensing. vol. 11, n° 2072-4292, pp. 1028, 20/06/2026)
LOV, INSU - CNRS, SU, CNRS, IMEV, INSU - CNRS, SU, CNRS, EBD, CSIC, IAFE, CONICET, UBA, CSIRO, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Shaping adaptive governance in estuarine cities Bordeaux Metropole and Gironde estuary facing global change
URBEST research project examine emergent adaptive governance in estuarine cities in a context of climate change.
(pp. 12, 20/06/2026)
UR ETBX, IRSTEA, UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
EStimating Contaminants tRansfers Over Complex food webs (ESCROC): An innovative Bayesian method for estimating POP's biomagnification in aquatic food webs
Pollution greatly impacts ecosystems health and associated ecological functions. Persistent Organic Pollutants (POPs) are among the most studied contaminants due to their persistence, bioaccumulation, and toxicity potential. Biomagnification is often described using the estimation of a Trophic Magnification Factor (TMF). This estimate is based on the relationship between contamination levels of the species and their trophic level. However, while the estimation can be significantly biased in relation to multiple sources of uncertainty (e.g. species physiology, measurement errors, food web complexity), usual TMF estimation methods typically do not allow accounting for these potential biases. More accurate and reliable assessment tool of TMFs and their associated uncertainty are therefore needed in order to appropriately guide chemical pollution management. The present work proposes a relevant and innovative TMF estimation method accounting for its many variability sources. The ESCROC model (EStimating Contaminants tRansfers Over Complex food webs), which is implemented in a Bayesian framework, allows for a more reliable and rigorous assessment of contaminants trophic magnification, in addition to accurate estimations of isotopes trophic enrichment factors and their associated uncertainties in food webs. Similar to classical mixing models used in food web investigations, ECSROC computes diet composition matrices using isotopic composition data while accounting for contamination data, leading to more robust food web descriptions. As a demonstration of the practical application of the model, ESCROC was implemented to revisit the trophic biomagnification of 5 polyfluoroalkyl substances (PFAS) in a complex estuarine food web (the Gironde, SW France). In addition to the TMF estimate and 95% confidence intervals, the model provided biomagnification probabilities associated to the investigated contaminants.
(Science of the Total Environment. vol. 658, n° 0048-9697, pp. 638-659, 20/06/2026)
UR EABX, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LPTC, UB, CNRS, ISM, UB, INC-CNRS, CNRS
Correlating three centuries of historical and geological data for the marine deposit reconstruction of two depositional environments of the French Atlantic coast
This paper details a high-resolution record of French Atlantic coast extreme wave events using a multi-proxy analysis of dated sedimentary deposits. Two lagoons 1) the Petite Mer de Gâvres and 2) the Traicts du Croisic were chosen to identify damaging storm events from the last 300 years with Beeker sampling, 210Pb and 137Cs dating and sedimentary analysis. Using two new geochemical proxies in the French Atlantic coast, Sr/Fe and Ca/Ti, shows that several storminess events are reported in the nine cores drilled. By correlation with historical archives, seven major storms are confirmed: 1924 CE, 1940 CE, 1972 CE, 1977 CE, 1990 CE, 1999 CE, and an 1896 CE highly damaging event. Four other XIXth and XVIIIth century extreme wave event correlations are also proposed from this multi-proxy analysis: 1775 CE, 1811 CE, 1838 CE and 1876 CE. Societal and natural impacts caused by these coastal floods are revealed using our dense and varied historical archives.
(Marine Geology. vol. 407, n° 0025-3227, pp. 181-191, 20/06/2026)
OSUNA, UA, UN UFR ST, UN, IFSTTAR, INSU - CNRS, Cnam, CNRS, IMT Atlantique, IMT, LETG - Nantes, UNICAEN, NU, EPHE, PSL, UBO EPE, UR2, CNRS, IGARUN, UN, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Plant interactions shape pollination networks via nonadditive effects
Plants grow in communities where they interact with other plants and with other living organisms such as pollinators. On the one hand, studies of plant–plant interactions rarely consider how plants interact with other trophic levels such as pollinators. On the other, studies of plant–animal interactions rarely deal with interactions within trophic levels such as plant–plant competition and facilitation. Thus, to what degree plant interactions affect biodiversity and ecological networks across trophic levels is poorly understood. We manipulated plant communities driven by foundation species facilitation and sampled plant–pollinator networks at fine spatial scale in a field experiment in Sierra Nevada, Spain. We found that plant–plant facilitation shaped pollinator diversity and structured pollination networks. Nonadditive effects of plant interactions on pollinator diversity and interaction diversity were synergistic in one foundation species networks while they were additive in another foundation species. Nonadditive effects of plant interactions were due to rewiring of pollination interactions. In addition, plant facilitation had negative effects on the structure of pollination networks likely due to increase in plant competition for pollination. Our results empirically demonstrate how different network types are coupled, revealing pervasive consequences of interaction chains in diverse communities.
(Ecology. vol. 100, n° 0012-9658, pp. e02619, 20/06/2026)
UZH, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UNIROMA, UAL, OUMNH, LSV Angers, LSV, ANSES, UNIBO
Environmental fate of chlordecone in coastal habitats: recent studies conducted in Guadeloupe and Martinique (Lesser Antilles)
The organochlorine pollution by chlordecone, an insecticide spread in the past in banana plantations, is now recognized as a major ecological, economic and social crisis in Guadeloupe and Martinique Islands. Due to its physical and chemical properties, this molecule is particularly persistent in the natural environment. Volcanic soil of Guadeloupe and Martinique contain allophanes (amorphous clays), which favor chlordecone trapping due to their structure and physical properties. Thus, with this trapping ability, allophanes could constitute a vector allowing chlordecone to contaminate runoff waters, and finally the sea. In the present publication, several studies recently conducted in the Lesser Antilles have been compiled in order to evaluate the desorption of chlordecone from allophanes when arriving in the estuarine environment and to determine the transfer of chlordecone along marine trophic food webs. The experiments showed that 20% of the initial quantity of chlordecone was released from allophones in estuarine conditions and 10% in marine environment. These results could explain the high level of contamination found in the suspended organic matter and zooplankton in the coastal areas located downstream the contaminated watersheds. The contamination of the marine food webs of mangroves seagrass beds and coral reefs, is dominated by a contamination 'by bath" in littoral waters containing chlordecone and by bioamplification seawards.
(Environmental Science and Pollution Research, n° 0944-1344, 20/06/2026)
BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IFREMER, ISM, UB, INC-CNRS, CNRS, ULiège
Temporal variability of lagoon–sea water exchange and seawater circulation through a Mediterranean barrier beach
The subterranean flow of water through sand barriers between coastal lagoons and the sea, driven by a positive hydraulic gradient, is a net new pathway for solute transfer to the sea. On the sea side of sand barriers, seawater circulation in the swash‐zone generates a flux of recycled and new solutes. The significance and temporal variability of these vectors to the French Mediterranean Sea is unknown, despite lagoons constituting ~ 50% of the coastline. A one‐dimensional 224Raex/223Ra reactive‐transport model was used to quantify water flow between a coastal lagoon (La Palme) and the sea over a 6‐month period. Horizontal flow between the lagoon and sea decreased from ~ 85 cm d−1 during May 2017 (0.3 m3 d−1 m−1 of shoreline) to ~ 20 cm d−1 in July and was negligible in the summer months thereafter due to a decreasing hydraulic gradient. Seawater circulation in the swash‐zone varied from 10 to 52 cm d−1 (0.4–2.1 m3 d−1 m−1), driven by short‐term changes in the prevailing wind and wave regimes. Both flow paths supply minor dissolved silica fluxes on the order of ~ 3–10 mmol Si d−1 m−1. Lagoon–sea water exchange supplies a net dissolved inorganic carbon (DIC) flux (320–1100 mmol C d−1 m−1) two orders of magnitude greater than seawater circulation and may impact coastal ocean acidification. The subterranean flow of water through sand barriers represents a significant source of new DIC, and potentially other solutes, to the Mediterranean Sea during high lagoon water‐level periods and should be considered in seasonal element budgets.
(Limnology and Oceanography. vol. 64, n° 0024-3590, pp. 2059-2080, 20/06/2026)
LEGOS, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, CEREGE, IRD, INRA, AMU, CdF (institution), INSU - CNRS, CNRS, GET, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, TropWATER, JCU, SBU, SUNY, GEOMAR