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
A new species of Chaetozone (Polychaeta, Cirratulidae) from the Bay of Biscay offshore France, together with a review of Chaetozone species from the North Atlantic and adjacent waters
A new cirratulid species of the genus Chaetozone has been discovered offshore in fine muddy sediments in the Bay of Biscay, France. This species is unusual in having an expanded fusiform anterior body region and numerous subdermal glands along the entire body that produce an elaborate and distinctive pattern when stained with Methyl Green. The new species is compared with closely related congeners and a review of Chaetozone species from the North Atlantic Ocean is presented.
(Zootaxa. vol. 4312, n° 1175-5326, pp. 565, 30/08/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Biotransformation, antioxidant and histopathological biomarker responses to contaminants in European and American yellow eels from the Gironde and St. Lawrence estuaries
Since the early 1980s, populations of American (Anguilla rostrata) and European eels (Anguilla anguilla) have suffered a sharp decline. The causes of their decline are likely multifactorial and include chemical pollution. A field study was conducted in eight sites varying in organic and metal contamination along the St. Lawrence (Eastern Canada) and Gironde (France) systems to investigate the relationships among contaminants, biological characteristics and biotransformation, antioxidant and histopathological biomarkers in eels from both species. For A. rostrata, no major influences of persistent organic contaminants on biomarkers were identified. For A. anguilla, eels from the most contaminated site expressed higher surface of MelanoMacrophage Centers (MMCs) and eels from another contaminated site expressed higher amount of spleen lipofuscin pigment. These two histopathological biomarkers were also associated with aging. Compared to eels from the cleanest French site, higher hepatic catalase activity and density of MMC in eels from contaminated sites was related to higher concentration of organic (DDT and metabolites, sum of PCBs, sum of PBDEs) and inorganic (Hg and Cd) contaminants. In both species, a higher deposition of spleen hemosiderin pigment was measured in eels from the most brackish sites compared to eels living in freshwater environments. Our results suggest an association between higher hemosiderin pigment and metal contamination (As for A. anguilla and Pb for A. rostrata). Parasitism by A. crassus was observed in European eels from freshwater sites but not in eels from brackish habitats. Overall, contamination may pose a greater risk for the health of European compared to American eels.
(Chemosphere. vol. 188, n° 0045-6535, pp. 292-303, 28/08/2017)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS