Typologie des habitats marins benthiques de la Manche, de la Mer du Nord et de l'Atlantique - VERSION 3
Ce rapport présente la version actualisée de la partie « Atlantique » du référentiel national des habitats marins benthiques en expliquant les modifications opérées. La mise à jour de la partie marine du référentiel européen EUNIS ainsi que les échanges avec les benthologues ont conduit à revoir les principes généraux de la typologie. La structure hiérarchique a été modifiée en débutant au premier niveau par des combinaisons de l’étagement et des types de substrat et ce, de manière à être le plus proche possible de la nouvelle version d’EUNIS. A la suite de ce premier niveau, révisé intégralement, les habitats listés dans la précédente version de la typologie ont été replacés au sein de la combinaison étage/substrat pertinente. Un effort particulier a été réalisé pour définir et homogénéiser la terminologie utilisée. La typologie a été complétée par de nouveaux habitats émanant de la bibliographie et de propositions directes d’experts. Enfin, les points nécessitant l’acquisition de nouvelles connaissances scientifiques sont également mentionnés.
(pp. 52 pages, 01/03/2019)
PatriNat, MNHN, CNRS, AFB, AD2M, SU, CNRS, SBR, SU, CNRS, DYNECO, IFREMER, ISYEB, MNHN, EPHE, PSL, SU, CNRS, UA, M2C, UNICAEN, NU, INSU - CNRS, UNIROUEN, NU, CNRS, ABICE, AD2M, SU, CNRS, SBR, SU, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LERAR, COAST, IFREMER, DGD.REVE, MNHN, SBR, SU, CNRS, FR2424, SBR, SU, CNRS, LEP, EEP, IFREMER, LIENSs, INSU - CNRS, ULR, CNRS, ECOMAP, AD2M, SU, CNRS, SBR, SU, CNRS
Transcriptome-wide analysis of wild Asari (=Manila) clams affected by the Brown Muscle Disease: Etiology and impacts of the disease
Recently, we reported an emerging pathology named Brown Muscle Disease (BMD) affecting Asari clams inhabiting the most productive area for this species in France, the Arcachon Bay. The main macroscopic feature of the pathology relies on the atrophy of the posterior adductor muscle, affecting the ability of clams to burry. The research of the etiological agent of BMD privileged a viral infection. Contrary to healthy clams, infected animals are always found at the surface of the sediment and exhibit 30 nm virus-like particles in muscle, granulocytic and rectal cells. In order to get more insights on the etiology and impacts of the BMD on clams, we took advantage in the present study of next generation sequencing technologies. An RNA-Seq approach was used (i) to test whether viral RNA sequences can be specifically found in the transcriptome of diseased animals and (ii) to identify the genes that are differentially regulated between diseased and healthy clams. Contrary to healthy buried animals, in diseased clams one sequence showing extensive homologies with retroviridae-related genes was detected. Among the biological processes that were affected in diseased clams, the synaptic transmission process was the most represented. To deepen this result, a new sampling was carried out and the transcription level of genes involved in synaptic transmission was determined in healthy and diseased clams but also in clams with no visible sign of pathology but located at the surface of the sediment. Our findings suggest that muscle atrophy is a latter sign of the pathology and that nervous system could be instead a primary target of the BMD agent.
(Fish and Shellfish Immunology. vol. 86, n° 1050-4648, pp. 179-185, 01/03/2019)
µVIS X-ray Imaging Centre, VIM (UR 0892), INRA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Quantifying the impacts of artisanal gold mining on a tropical river system using mercury isotopes
Total mercury (Hg) concentrations, speciation and isotopic composition were analyzed in soils and sediments along the Oyapock River (French Guiana), subjected to intense artisanal and small-scale gold-mining (ASGM). As a large part of these mining activities is illegal, amalgamation of gold with liquid Hg(0) is the main exploitation process. Further chemical analyses were performed along the same river, in bedrocks, waters, suspended matter, sediments and soils in both pristine and gold-mining areas. Physico-chemical parameters and Hg isotopic composition measured in the different matrices of the pristine area allowed us to trace the origin and fate of the natural Hg. We find that Hg in tropical topsoils preferentially originates from gaseous Hg(0) uptake by plants rather than from wet deposition. A strong negative mass independent fractionation (MIF) between topsoils and deeper horizons was attributed to pre-anthropogenic atmospheric Hg deposition with low MIF that leached to deeper horizons. Hg isotopic composition in pristine sediments confirmed that Hg in river sediments mainly originates from deep soil erosion and is subjected to aquatic photochemical reduction. Combining a Hg-isotope binary mixing model with a multiple linear regression based on physico-chemical parameters, we determined that the currently mined creek sediments are contaminated in Hg. This excess of Hg, which can represent more than half of the total Hg concentration, mainly originates from liquid
(Chemosphere. vol. 219, n° 0045-6535, pp. 684-694, 01/03/2019)
LEFE, INEE-CNRS, CNRS, UT3, Comue de Toulouse, CNRS, Toulouse INP, Comue de Toulouse, LMTG, UT3, Comue de Toulouse, CNRS, GET, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS, LMV, UBP, INSU - CNRS, UJM, UJM EPE, CNRS, GFZ, MIO, IRD, AMU, INSU - CNRS, UTLN, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, GIS, GET, IRD, UT3, Comue de Toulouse, INSU - CNRS, CNES, CNRS
A Cool, Nutrient‐Enriched Eastern Equatorial Pacific During the Mid‐Pleistocene Transition
The emergence of high-amplitude, low-frequency glacial-interglacial cycles during the mid-Pleistocene climate transition (MPT; 800–1,200 ka) is associated with global cooling. In the eastern equatorial Pacific, sea surface temperatures cooled, and the upwelling-induced cold tongue expanded significantly during the MPT. Here we use sedimentary records of iron, biogenic silica, and nutrient-nitrogen consumption to evaluate biogeochemical changes hypothesized to accompany the cold tongue expansion. Our results suggest that the eastern equatorial Pacific of the MPT hosted surface waters with higher nitrate contents and biogenic silica production relative to the last 600 ka. Increased production occurred despite low iron supply. We attribute this to enhanced upwelling and nutrient enrichment of thermocline waters, both likely related to the northward migration of Southern Ocean fronts. The return of these fronts to their southward positions after the MPT may be associated with stronger drawdown of nutrients and, potentially, atmospheric CO2 in the Southern Ocean.
(Geophysical Research Letters. vol. 46, n° 0094-8276, pp. 2187-2195, 28/02/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Comparative biomarker responses in Japanese medaka (Oryzias latipes) exposed to benzo[a]pyrene and challenged with betanodavirus at three different life stages
It is now well documented that several contaminants can modulate the fish immune system, leading to disrupted host resistance against pathogens and increased incidence of disease. Since fish are usually co-exposed to chemicals and pathogens in the natural environment, analysis of the immunotoxic effects of pollutants is particularly relevant. The authorities in the European Union have recommended the development of toxicity assays on cell cultures and embryos, as an alternative to testing in vertebrates. This is why in our study, a fish immune challenge assay was developed for the early life stages of Japanese medaka to evaluate and compare the relevance of new biomarkers. Fish were exposed to benzo[a]pyrene (BaP), a model pollutant, for 8days at the embryonic stage, or for 48h at the larvae and juvenile stages, and fish were infected with betanodavirus by bath-challenge of 10TCID/mL. Biometric changes and induction of malformations were observed after embryonic exposure. DNA damage and induction of EROD activity were recorded at the end of all chemical exposures. Viral infection increased the mortality rate significantly and disturbed the behavior of fish after light stimulation. While BaP exposure increased swimming speed, betanodavirus infection slowed swimming activity. In larvae co-exposed to BaP and the virus, the viral titer in the whole body was higher than in fish infected only with the virus. This study highlighted the sensitivity and usefulness of the immune challenge assay on the early life stages of Japanese medaka to evaluate the toxic effects of pollutants.
(Science of the Total Environment. vol. 652, n° 0048-9697, pp. 964-976, 20/02/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ANSES, VIMEP, ANSES
Interactive effects of climate and topography on soil salinity and vegetation zonation in North‐African continental saline depressions
Questions: Complex distal factors such as climate and topography can interact to drive direct proximal ecological gradients and vegetation zonation in geographical and ecological space, in particular salinity and soil moisture in arid climates. We pose the following questions: (a) Does increasing climate aridity alter direct water and salinity gradients along topography gradients in saline depressions in arid climates? (b) Do these effects of increasing climate aridity in turn alter vegetation life-form zonation? (c) Does increasing climate aridity alter community composition along the zonation? Study site: Continental saline depressions of the Mediterranean arid climate of central and southern Tunisia. Methods: We sampled vegetation structure, diversity, and composition and environmental variables at five positions along the topography gradient of continental saline depressions in wet and dry conditions. Results: Climate aridity altered salinity gradients and vegetation structure but not diversity and community composition. Salinity increased with increasing aridity at the lowest positions of the depressions but decreased with increasing aridity at their highest positions. Total vegetation cover and relative abundance of therophytes decreased, whereas relative abundance of chamaephytes increased with increasing climate aridity at the upper habitats. Conclusions: Ecological factors acting at a regional scale can alter the spatial variation of other ecological factors acting at smaller spatial scales, ultimately explaining vegetation zonation in continental saline depressions. Salinity collapses with increasing aridity.
(Journal of Vegetation Science. vol. 30, n° 1100-9233, pp. 312-321, 15/02/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Overtide generation by wind-induced waves in a tidal inlet of SW France
Quarter-diurnal tidal constituents are linked to tidal asymmetries and play a role in the morphodynamic evolution of inlets, estuaries and lagoons. A two-year non-continuous dataset of current velocities and waves was used to improve understanding on the generation of quarter-diurnal harmonics. Data analysis provides evidence for the generation of quarter-diurnal harmonics by wind-induced waves. Data were collected at the entrance to the Arcachon Lagoon, a mixed-energy tidal inlet in Southwest France. Temporal variability of the quarter-diurnal tidal current was identified through wavelet analysis of the main velocity component (alongshore velocity). Quarter-diurnal velocity amplitudes, bottom and wave stresses, and significant wave height suggested a linkage between quarter-diurnal amplification and wave action. Both significant wave height and wave stress were coherent with quarter-diurnal current amplitudes at synoptic frequencies, most markedly in winter months of both years observed. These coherences corroborated the hypothesis that wind-induced waves enhance bottom stresses that can generate and augment quarter-diurnal currents in this region.
(Continental Shelf Research. vol. 174, n° 0278-4343, pp. 66-75, 15/02/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
A dual nanosecond-pulsed laser setup for nanocomposite synthesis—Ag nanoparticles in Al 2 O 3 /VO 2 matrix
(Journal of Applied Physics. vol. 125, n° 0021-8979, pp. 054301, 07/02/2019)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IRCER, IPAM, UNILIM, INC-CNRS, CNRS, IRCER-AXE2, IRCER, IPAM, UNILIM, INC-CNRS, CNRS
Where has the pollution gone? A survey of organic contaminants in Ho Chi Minh city / Saigon River (Vietnam) bed sediments
A wide range of persistent organic chemicals, including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), some insecticides, as well as polybrominated diphenyl ethers (PBDEs) and some perfluoroalkyl substances (PFASs) were analyzed in 17 bed sediments collected along the Saigon River and at adjacent canal mouths from upstream to downstream in Ho Chi Minh City (Vietnam). Concentrations were rather low for PAHs, as well as for legacy PCBs and dichloro-diphenyl-trichlorethane and metabolites (DDTs), or below detection limits for several PFASs and all PBDEs measured. Several insecticides (chlorpyrifos-ethyl, and the pyrethroids cypermethrin and λ-cyhalothrin) displayed rather high concentrations at a few sites within the city. There was no distinct upstream – downstream trend for PAHs, (DDTs) or PCBs. Although adjacent canal sediments tended to be more contaminated than Saigon River sediments, the differences were not significant. Emissions are almost certainly substantial for PAHs, and probably also for other contaminants such as PBDEs and some PFASs. During the dry season, contaminants are presumably stored in the city, either in canals or on urban surfaces. Heavy rainfall during the monsoon period carries away contaminated particle flows into the canals and then the Saigon River. The strong tidal influence in the river channel hinders the accumulation of contaminated particles. Contaminated deposits should accordingly be investigated further downstream in depositional environments, such as the mangrove.
(Chemosphere. vol. 217, n° 0045-6535, pp. 261-269, 01/02/2019)
IRSTEA, LEHNA, UCBL, ENTPE, CNRS, GéHCO, UT, NEOLAiA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, EPFL, HCMUS, CARE, HCMUT, VNU-HCM, IGE, IRD, Grenoble INP, INSU - CNRS, CNRS, UGA [2016-2019], Fédération OSUG
High-resolution foraminifer stable isotope record of MIS 19 at Montalbano Jonico, southern Italy: A window into Mediterranean climatic variability during a low-eccentricity interglacial
(Quaternary Science Reviews. vol. 205, n° 0277-3791, pp. 106-125, 01/02/2019)
LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, PALEOCEAN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, CEREGE, IRD, INRA, AMU, CdF (institution), INSU - CNRS, CNRS, LBP, CNRS, UNISTRA, Université de Haute-Alsace (UHA), CNRS, HNHP, MNHN, UPVD, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS