The southern Norwegian Sea during the last 45 ka: hydrographical reorganizations under changing ice‐sheet dynamics
The last glacial millennial Heinrich and Dansgaard–Oeschger events have been the subject of many studies in recent decades. However, significant uncertainties remain, notably regarding associated oceanic mechanisms. Here we investigate the evolution of hydrographical conditions in the 3–41 ka cal BP interval of core MD99-2285 located in the southern Norwegian Sea. Our results reveal an unusual scheme with: (i) warm Greenland interstadials marked by a relatively cold and homogeneous upper water column seasonally ice-covered and active deep water formation, (ii) cold Greenland and Heinrich stadials marked by a warm, low-salinity and nearly sea ice-free surface layer with iceberg calving, separated by a strong halocline from a colder and saltier subsurface layer, as well as strongly reduced deep convection, and (iii) close to modern Holocene oceanic conditions, but showing significant differences from interstadial conditions. Hence, our work strongly suggests different deep-water convection modes in the Nordic Seas, with, notably, interstadial deep water formation mainly forced by brine release. According to our results, the transition from the glacial mode of deep water formation to the modern open ocean convection mode might have occurred at the end of deglaciation/beginning of the Holocene, when both modes probably occurred.
(Journal of Quaternary Science. vol. 32, n° 0267-8179, pp. 908-922, 18/09/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Swelling behavior of polymeric membranes to metalworking fluids
In some working places, such as metal manufacturing or automotive services, mechanical hazards commonly occur along with chemical hazards, particularly metalworking fluids (MWFs). The presence of these chemicals could modify the properties of gloves made from polymeric materials and thus reduce their protective properties against chemical contamination (solvent, MWFs) and mechanical risks (puncture and cutting). This work focused on determining the swelling characteristics and the resistance of six polymeric membranes which were exposed to seven industrial MWFs. We found that the swelling tests can be used to classify the potential of coating polymers in descending order of their resistance to MWFs: nitrile, polyurethane>poly(vinyl chloride), neoprene> butyl, latex. The analysis by multiple linear regression showed, for the first time, that the density or the viscosity-gravity constant of the fluid and Hansen’s solubility parameters of the polymers have a significant impact on the swelling of polymer. For the first time, two new multiple regression models have been proposed, to predict the swelling phenomena of polymers under various MWFs with an accuracy of 80%. The effect of temperature on mechanical properties and morphology of material was also examined
(Journal of Applied Polymer Science. vol. 135, n° 0021-8995, pp. 45717, 12/09/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, IRSST
Parasite interactions in the bioturbator Upogebia pusilla (Decapoda: Gebiidae): a case of amensalism?
The mud shrimp Upogebia pusilla is a deep-burrowing bioturbator widespread along the Northeast Atlantic and Mediterranean coasts, where it is recognized as an ecosystem engineer. Parasitism is an important factor impacting such species’ activities, and thus ecosystem functioning. At least two parasite species occur in U. pusilla: the bopyrid isopod Gyge branchialis and an undescribed trematode. This study, carried out in Arcachon Bay, France (44°40′N, 1°10′W), over 2 years (2014–2015), had two goals: (1) to identify the trematode occurring in U. pusilla and (2) to assess the interactions between the two parasites within their host. Using molecular techniques, the trematode was identified as Maritrema sp. (Microphallidae). Monthly samples taken over 2 years at a single site, and a ten-site spatial survey in June 2014 showed that there was a negative association in the occurrence of the two parasites in their host over time and amongst sites: bopyrid-infested mud shrimp harbored lower trematode infections compared to bopyrid-free individuals. In addition, the abundance of trematodes was lower in the bopyrid-infested gill compared to the uninfested gill of bopyrid-infested individuals. It suggests that G. branchialis interferes with Maritrema sp. establishment in the mud shrimp. Conversely, the trematode appeared not to have a negative effect on bopyrid presence. The reduction of Maritrema sp. infection by G. branchialis is mainly due to the alteration of U. pusilla fitness (indirect interaction), and to a lesser extent, to overlap of parasites’ niches (direct interaction). Accordingly, interactions between these two parasites can be classified as amensalism.
(Marine Biology. vol. 164, n° 0025-3162, 11/09/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Quantification of twelve families of emerging pollutants in road and car park runoff
(11/09/2017)
LEESU, ENPC, UPEC UP12, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA
Envenimation par une méduse d’eau douce ( Craspedacusta sowerbii ) en France métropolitaine
Marine envenomations are well known. Freshwater jellyfish, the basic form of swimming medusae, are not as popular as seawater ones. Craspedacusta sowerbii is the only freshwater species in Europe and the only species with a worldwide distribution. We describe the first case report of cutaneous envenomation by the freshwater jellyfish Craspedacusta sowerbii in a French lake, with a favorable evolution. Among other things, water temperature increasing as well as nutrient enrichment of aquatic environment, are favorable for development of the medusae form of Craspedacusta sowerbii. It is suspected that envenomation cases may increase to the future. Several parameters may affect envenomation severity: the cnidocyst, the venom components, affected victim body surface area, initial patient state, contact time, discharged cnidocysts number. These factors can lead to a wide variety of symptoms. No study has been reported about the Craspedacusta sowerbii venom components. Additional studies are warranted to propose effective therapeutics.
(Toxicologie Analytique et Clinique. vol. 29, n° 2352-0078, pp. 325-330, 01/09/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Seasonal variation of transcriptomic and biochemical parameters of cockles ( Cerastoderma edule ) related to their infection by trematode parasites
Bivalve populations are controlled by several biotic and abiotic factors. Parasitism is among the biotic factors but is often neglected. In the present study, we focused on the transcriptomic and biochemical responses of Cerastoderma edule when parasitized as first intermediate host by the trematode Bucephalus minimus (sporocyst, the most damaging stage), and taking into account seasonal patterns. In order to test the hypothesis that the presence of B. minimus compromises cockle regular gene expression and biochemical performance and increases their vulnerability to other parasite species infection, cockles were sampled every other month during one year in Arcachon Bay (French Atlantic coast). Overall, results showed that B. minimus induced its first intermediate host defence mechanism against oxidative stress (mainly at gene level), increased host metabolism and energy demand especially in summer (revealed at both gene and biochemical level, although without significant differences) and was accompanied by a higher metacercariae abundance. Results allowed to accept the posted hypothesis and to conclude that transcriptomic and biochemical markers can provide additional and ecologically relevant information about parasite effects on their hosts, reflecting the invasion effects of pathogens but also the environmental conditions that animals experience.
(Journal of Invertebrate Pathology. vol. 148, n° 0022-2011, pp. 73-80, 01/09/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Traitement de données en sciences environnementales
Traitement de données en sciences environnementales présente les méthodes d’analyses de tableaux de données multivariées les plus couramment utilisées dans les différentes disciplines des sciences environnementales – de la géochimie à l’écologie. Il examine leurs principes, leurs conditions d’application, les moyens de les mettre en œuvre, via l’utilisation du logiciel R, ainsi que la manière de les interpréter justement. La variété des analyses exposées permet le traitement de petits comme de grands jeux de données. L’ouvrage précise les manières d’explorer et de préparer ces données en amont de l’analyse – en accord avec les objectifs et la stratégie scientifiques de l’étude –, de les traiter au préalable, d’établir une structure d’objets (stations/dates) ou de variables d’intérêt et de mettre en avant les paramètres explicatifs de ces structures (la façon, par exemple, dont la physico-chimie influence la structure biologique obtenue).
(01/09/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
First data on three bivalve species exposed to an intra-harbour polymetallic contamination (La Rochelle, France)
Evaluating diffuse sediment contamination in the environment is a major concern with the aim of reaching a good chemical and ecological state of the littoral zone. In this study the risks of chronic chemical contamination and consequences in the bivalves Crassostrea gigas, Mytilus sp. and Mimachlamys varia were evaluated in coastal environments. The objective here was to understand the anthropological phenomena that affect the functioning of the marina of La Rochelle (semi-closed environment). Harbours seeking ecomanagement accreditations (such as the international reference ISO 14001) constitute zones of interest to implement biomonitoring studies. The biological effects of chemical pollution in the Marina of La Rochelle were studied to develop a multi-biomarker biomonitoring approach on specific marine species of this site. Moreover, a genetic (DNA barcoding) approach was applied to validate the species identity of collected bivalves. Of the three species tested the scallop, M. varia, was the most sensitive to metal exposure.
(Comparative Biochemistry and Physiology - Part C: Comparative Pharmacology and Toxicology. vol. 199, n° 0742-8413, pp. 28 - 37, 01/09/2017)
LIENSs, INSU - CNRS, ULR, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Vegetation and environmental changes at the Middle Stone Age site of Wonderkrater, Limpopo, South Africa
Abstract Wonderkrater, a Middle Stone Age site in the interior of South Africa, is a spring and peat mound featuring both paleoclimatic and archaeological records. The site preserves three small MSA lithic assemblages with age estimates of 30 ka, >45 ka and 138.01±7.7 ka. Here we present results of the pollen analysis of a core retrieved from the middle of the peat mound, which covers, with hiatuses, the timespan between ca. 70±10 ka and 30 ka. Pollen percentages of terrestrial, local aquatic, and semi-aquatic plants reveal changes in the regional climate and in the water table of the spring. Results identify regional wet conditions at ca. 70±10 ka, followed by a dry and a wet period between 60 ka and 30 ka. Superimposed on these three phases, recurring changes in the size and depth of the water table are observed between >45 ka and 30 ka. Wet conditions at 70 ka and 30 ka are tentatively correlated here with Marine Isotope Stage 4 and Heinrich Stadial 3, respectively. A warm and dry savanna landscape was present during human occupation older than 45 ka, and a wet phase was contemporaneous with the final occupation, dated at ~30 ka.
(Quaternary Research. vol. 88, n° 0033-5894, pp. 313-326, 01/09/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, PACEA, UB, CNRS, EPHE, PSL, WITS
Link between Indian monsoon rainfall and physical erosion in the Himalayan system during the Holocene
Mineralogical and geochemical analyses conducted on cores located on the active channel-levee system of the northern Bengal Fan are used to establish changes in the weathering pattern and the sediment transport of the Himalayan system, and evaluate the effect of Indian summer monsoon rainfall during the Holocene. Our data indicate that during the Holocene, sediments from the northern Bengal Fan originate mainly from the G-B river system without any significant changes in the relative contribution of these rivers. From 9.8 to around 6 ka, relatively low smectite/(illite1chlorite) ratios and relatively high K/Si* ratios indicate high physical denudation rates of the Himalayan highlands together with a rapid transfer of the detrital material to the Bengal Fan. The period between 9.2 and 7 ka is associated to lower values of K/ Si* and corresponds to the maximum of Indian monsoon rainfall which indicates a more important chemical weathering material that rapidly transits by the G-B river system without a long storage in the Indo-Gangetic plain. From 6.0 ka to present day, higher smectite/(illite1chlorite) ratio and lower K/Si* ratio document a gradual increase of sediments originated from the Indo-Gangetic plain, characterized by higher degree of chemical weathering. During the last 2.5 ka, the drastic increase in the smectite/(illite1chlorite) ratio could be associated to enhanced alteration of the plain soils due to anthropogenic activity. The comparison of mineralogical and geochemical data with previous reconstructions of the Indian monsoon dynamic indicates a rapid response of erosion and sediment transfer of the G-B river system to changes of monsoon rainfall intensity.
(Geochemistry, Geophysics, Geosystems. vol. 18, pp. 3452 - 3469, 01/09/2017)
GEOPS, UP11, CNRS, EMBS, iSTeP, UPMC, CNRS, CR2P, MNHN, UPMC, CNRS, MNHN, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA, IPGP, INSU - CNRS, UPD7, UR, IPG Paris, CNRS, PALEOCEAN, LSCE, UVSQ, INSU - CNRS, CNRS, DRF (CEA), CEA