Investigation on the capabilities of low-cost and smartphone-based coastal imagery for deriving coastal state video indicators : applications on the upper mediterranean
This work deals with the implementation and operational use of low-cost and smartphone-based camera system for the purpose of coastal video monitoring. Capability of such system for coastal remote sensing is described in this study. Particularly, a small network of ©Solarcam has been implemented in Corsica Island (France) for purposes of coastline evolution, sandbar(s) detections and to investigate the influence of the Posidonia banquettes on morphological evolution. A new coastal indicator derived from video observation is presented. Furthermore, the second part deals with the description and application of image semantic segmentation procedures, developed in order to regionalize the main morphologies framed by web-cams. Such techniques can be apply for a range of applications: from shoreline evolution, sandbar(s) detection, algae identification and development of a warning system.
(27/05/2019)
BRGM, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
The Omega-3 Index of macrophytes to improve the assessment of the treatment performance of constructed wetlands receiving treated wastewater
The Omega-3 Index of macrophytes to improve the assessment of the treatment performance of constructed wetlands receiving treated wastewater.
(pp. 1, 26/05/2019)
CNRS, UR REVERSAAL, IRSTEA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IRSTEA
PLASTIC-Seine research project: Microplastic Flux and Impact on biota in the Seine estuary.
Microplastics (MP) pollution is of emerging concern. Although numerous studies were recently carried out on freshwater and biota contamination, studies focused on estuary ecosystems are scarce. Estuaries can indeed play a significant role in the transport and transfer of MP to the ocean and the estuarine hydrodynamics and salinity gradient can greatly affect both MP distribution and concentrations, as well as the occurrence and levels in biotic compartments. In this context, the Plastic-Seine project (2017-2020) involving six French laboratories was launched to study the occurrence and levels of MP in all compartments of the ecosystem of the Seine River estuary (France). The objectives are: i) to study the occurrence and levels of MP in the Seine estuary for abiotic compartments (water column and sediment), ii) to study the ingestion and levels of MP for seven emblematic species of the Seine estuary, i.e, the worm Hediste diversicolor, the copepod Eurytemora affinis, the mussel Mytulis edulis, the prawn Palaemon longirostris and 3 fish species Platichthys flesus, Solea solea and Dicentrarchus labrax and iii) to assess the potential impacts of MP exposure on biology traits, physiology and behavior of three species (Hediste diversicolor, Eurytemora affinis and Solea solea). Preliminary and main results are here presented and discussed. First results on abiotic compartements highlighted the presence of fibers and fragements in both the water colonn and sediments. Particles exhibited different forms depending on their origin and/or fragmentation. Most of particles were inferior to 1 mm and a high proportion of fragments and films was higlighted. Slight MP distribution changes were also observed between surface water and subsurface water. For the seven species, MP including fibers and fragements were found. The others analyses are in progress. For all species, a high variabilities between species and individuals was highligted. High presence of fragments were noticed for seabass and worms in comparison to other species. In the case of prawns, a large amount of MP and especially of fibers were also observed on the cuticle surface. Futher studies will investigate the potential impacts of MP exposure on biology traits, physiology, and behavior of three estuarine species and the MP trophic transfer to common sole’s food chain.
(26/05/2019)
LEESU, ENPC, UPEC UP12, BIOSSE, UCO, MMS, UM, UN UFR ST, UN, UFR SPB, UN, IFREMER, LERN, COAST, IFREMER, UMR MARBEC, IRD, IFREMER, UM, CNRS, LANIE, SEARS, DPC, CEA-DES (ex-DEN), LOG, INSU - CNRS, ULCO, CNRS, IRD [Ile-de-France], ULCO, SEBIO, INERIS, URCA, ULH, NU, URCA, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EPOC
First record of the non-indigenous Isopoda Synidotea laticauda Benedict, 1897 in the Seine Estuary (Normandy, France)
The northeastern Pacific isopod Synidotea laticauda Benedict, 1897 is reported for the first time in the French part of the English Channel. Specimens have been found in 2017 in a pebble habitat of the Seine Estuary (Normandy, France). Its occurrence in the Seine Estuary is probably related to international maritime traffic, which is important around the major seaports of the Seine Estuary: Le Havre and Rouen.
(An Aod - Les cahiers naturalistes de l’Observatoire marin. vol. 8, n° 2263-5718, pp. 11-20, 25/05/2019)
PatriNat, MNHN, CNRS, OFB, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, CSLN, ULH, NU
Latitudinal variations in δ30Si and δ15N signatures along the Peruvian shelf: quantifying the effects of nutrient utilization versus denitrification over the past 600 years
Abstract. The stable sedimentary nitrogen isotope compositions of bulk organic matter (δ15Nbulk) and the silicon isotope composition of diatoms (δ30SiBSi) both mainly reflect the degree of past nutrient utilization by primary producers. However, in ocean areas where anoxic and suboxic conditions prevail, the δ15Nbulk signal ultimately recorded within the sediments is also influenced by water column denitrification, causing an increase in the subsurface δ15N signature of dissolved nitrate (δ15NO3-) upwelled to the surface. Such conditions are found in the oxygen minimum zone off the coast of Peru, where, at present, an increase in subsurface δ15NO3- from north to south along the shelf is observed due to ongoing denitrification within the poleward-flowing subsurface waters, while the δ30Si signature of silicic acid (δ30Si(OH)4) at the same time remains unchanged. Here, we present three new δ30SiBSi records between 11 and 15∘ S and compare these to previously published δ30SiBSi and δ15Nbulk records from Peru covering the past 600 years. We present a new approach to calculate past subsurface δ15NO3- signatures based on the direct comparison of δ30SiBSi and δ15Nbulk signatures at a latitudinal resolution for different time periods. Our results show that, during the Current Warm Period (CWP, since 1800 CE) and prior short-term arid events, source water δ15NO3- compositions have been close to modern values, increasing southward from 7 to 10 ‰ (between 11 and 15∘ S). In contrast, during the Little Ice Age (LIA) we calculate low δ15NO3- values between 6 ‰ and 7.5 ‰. Furthermore, the direct δ30SiBSi versus δ15Nbulk comparison also enables us to relate the short-term variability in both isotope compositions to changes in the ratio of nutrients (NO3-:Si(OH)4) taken up by different dominating phytoplankton groups (diatoms and non-siliceous phytoplankton) under the variable climatic conditions of the past 600 years. Accordingly, we estimate a shift from a 1:1 (or 1:2) ratio during the CWP and a 2:1 (up to 15:1) ratio during the LIA, associated with a shift from overall high nutrient utilization to NO3--dominated (and thus non-siliceous phytoplankton) utilization.
(Biogeosciences. vol. 16, n° 1726-4170, pp. 2163-2180, 23/05/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Suivis pluriannuels des transferts verticaux de pesticides dans des sols de vallée alluviale en monoculture de maïs irrigué
(pp. 23p., 21/05/2019)
CA 09, UCLouvain, CRA Occitanie, GET, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, AGIR, Toulouse INP, Comue de Toulouse, INP - PURPAN, Toulouse INP, Comue de Toulouse, INRAE
Caractérisation géochimique des changements paléoenvironnementaux au cours de l’Évènement Océanique Anoxique 2 (~94 Ma) dans le Bassin Vocontien (SE France)
Le passage Cénomanien-Turonien (~94 Ma) au Crétacé supérieur est marqué par une période de diminution de la quantité d’O2 dans les sédiments et la colonne d’eau et de perturbations biogéochimiques appelé Évènement Océanique Anoxique 2 (OAE 2). Comme l’ensemble des OAEs du Crétacé, l’OAE 2 s’est mis en place dans un contexte d’augmentation de la concentration en CO2 dans les océans et l’atmosphère, interprétée comme d’origine volcanique. L’hétérogénéité des réponses à cette perturbation globale suggère que des paramètres environnementaux régionaux ou locaux ont contribué au scénario de mise en place et d’évolution de l’OAE 2. L’objectif cette thèse est ainsi de déterminer le rôle de ces mécanismes à différentes échelles spatiales. La démarche consiste en une comparaison des conditions biogéochimiques associées à l’OAE 2 dans un bassin épicontinental, comme le Bassin Vocontien (SE France), avec les bassins océaniques mondiaux. La comparaison de données de géochimie organique (TOC, HI vs. OI), inorganique (enrichissements en éléments majeurs et traces, spéciation du fer) et isotopique (δ13C, δ15N, δ34S) de deux coupes du Bassin Vocontien semble indiquer que l’augmentation de la quantité de CO2 et de sulfates dans le bassin, associée à l’activité d’une Grande Province Volcanique, fut le facteur déclencheur de l’OAE 2. Par ailleurs, les hétérogénéités des conditions d’oxygénation semblent être majoritairement associées aux configurations géométriques des bassins et au taux de renouvellement des leurs eaux profondes, mais aussi aux conditions de productivité primaire influencés par les cycles de nutriments, et enfin aux paramètres climatiques régionaux.
(13/05/2019)
ISTerre, IFSTTAR, INSU - CNRS, USMB [Université de Savoie] [Université de Chambéry], CNRS, UGA [2016-2019]
Coupled ocean and atmospheric changes during Greenland stadial 1 in southwestern Europe
Paleoclimate reconstructions suggest that the complex variability within the Greenland stadial 1 (GS-1) over western Europe was governed by coupled ocean and atmospheric changes. However, few works from the North Atlantic mid-latitudes document both the GS-1 onset and its termination, which are often considered as single abrupt transition events. Here, we present a direct comparison between marine (alkenone-based sea surface temperatures) and terrestrial (pollen) data, at very high resolution (28 years mean), from the southwestern Iberian shelf record D13882. Our results reveal a rather complex climatic period with internally changing conditions. The GS-1 onset (GS-1a: 12890-12720 yr BP) is marked by a progressive cooling and drying; GS-1b (12720-12390 yr BP) is the coldest and driest phase; GS-1c (12390-12030 yr BP) is marked by a progressive warming and increase in moisture conditions; GS-1 termination (GS-1d: 12030-11770 yr BP) is marked by rapid switches between cool wet, cold dry and cool wet conditions. Although hydroclimate response was very unsteady throughout the GS-1 and in particular during its termination phase, the persistence of an open temperate and Mediterranean forest in southwestern Iberia during the entire episode suggests that at least some moisture was delivered via the Westerlies. We propose coupled ocean and atmospheric mechanisms to reproduce these scenaria. Changes in the strength of the Atlantic Meridional Overturning Circulation (AMOC) as well as variations in the North Atlantic sea-ice growth have favoured the displacement of the polar jet stream's latitudinal position and contributed to a complex spatial pattern and strength of the Westerlies across western Europe.
(Quaternary Science Reviews. vol. 212, n° 0277-3791, pp. 108-120, 01/05/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Moderate temperature elevation increase susceptibility of early-life stage of the Mediterranean mussel, Mytilus galloprovincialis to metal-induced genotoxicity.
The present study aims to evaluate the effects of copper and silver alone or along with a moderate temperature increase on embryonic development, DNA integrity and target gene expression levels in early life stages of Mytilus galloprovincialis. For this purpose, upon fertilized embryos were exposed to a sub-lethal concentration of Cu (9.54 μg/L), Ag (2.55 μg/L) and to the mixture of the two metals (Cu (6.67 μg/L) + Ag (1.47 μg/L)) along with a temperature gradient (18, 20 and 22 °C). In all experiments, larvae were exposed to stressors for 48 h except for those designed to DNA damage analysis exposed only for 24 h (before shell formation).Our results showed a significant increase in the percentage of malformed D-larvae (p < 0.05) with increasing temperature and exposure to silver and copper alone or in a mixture. Moreover, metal toxicity increased significantly (p < 0.05) with the temperature rise. Genotoxicity was evaluated using classic and modified with Formamidopyrimidine DNA glycosylase (Fpg) Comet assay. Results suggest that co-exposure to metals and temperature significantly increased DNA damage on mussel larvae with a more accentuated oxidative damage. A significant transcription modulation was observed for genes involved in DNA repair and DNA replication (p53, DNA ligase II and topoisomerase II) when larvae are exposed to a single stressor. However, in the case of multiple stresses, caspase involved in the cell apoptosis pathway was overexpressed. Our study suggests that mussel larvae exposed to a moderate increase in temperature may have a compromised ability to defend against genotoxicity. This is particularly relevant in the context of global warming and thermal pollution.
(Science of the Total Environment. vol. 663, n° 0048-9697, pp. 351-360, 01/05/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Evaluation des effets écotoxiques des rejets de STEP sur embryons de truite fario (Salmo trutta fario) encagés in situ
(01/05/2019)
ECOBIOP, INRA, UPPA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS