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See detailStructure, Functioning and Conservation of Coastal Vegetated Wetlands
Richir, Jonathan ULiege; Bouillon, Steven; Gobert, Sylvie ULiege et al

Book published by Frontiers Media S.A. (2020)

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See detailEditorial: Structure, Functioning and Conservation of Coastal Vegetated Wetlands
Richir, Jonathan ULiege; Bouillon, Steven; Gobert, Sylvie ULiege et al

Book published by Frontiers Media S.A. (2020)

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See detailZooplankton dynamics in a changing environment: A 13-year survey in the northwestern Mediterranean Sea
Fullgrabe, Lovina ULiege; Grosjean, P.; Gobert, Sylvie ULiege et al

in Marine Environmental Research (2020), 159

Dynamics of the subsurface (2–3 m) mesozooplankton (i.e., > 200 μm) in the Bay of Calvi (Corsica, France) were explored, combining time series (2004–2016) of 14 zooplankton groups, wind gusts, water ... [more ▼]

Dynamics of the subsurface (2–3 m) mesozooplankton (i.e., > 200 μm) in the Bay of Calvi (Corsica, France) were explored, combining time series (2004–2016) of 14 zooplankton groups, wind gusts, water temperature, nitrate and chlorophyll-a. Zooplankton data was obtained through image analysis. While contrasted group-specific seasonal patterns were observed, the most productive zooplankton annual event occurred in April (spring peak), concentrating on average 25% of the total annual abundance. A “typical” year was defined based on the annual succession of different community states, highlighting particular years (2007, 2015 and 2012) mainly characterized by weak spring peak. Environmental influences on the interannual variability of zooplankton were explored and while relationship between chlorophyll-a and zooplankton abundance was unclear, the availability of nutrients (December–March), potentially mediated via the wind regime (October–January) seemed to be essential to the occurrence of the spring peak. Additionally, we observed an influence of temperature, with winter thermal thresholds (between 12.1 °C and 13.4 °C) conditioning the spring peak. Also, the occurrence of lower annual abundances after 2010 was synchronous with the sharp increase of seawater warming trend, especially regarding winter temperature (0.30 °C.year-1). Finally, winter North Atlantic Oscillation (NAO) was found to be correlated to both winter water temperature and spring peak abundance, which suggests large-scale processes to impact regional zooplankton community. [less ▲]

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See detailTrace elements and oxidative stress in the Ark shell Arca noae from a Mediterranean coastal lagoon (Bizerte lagoon, Tunisia): are there health risks associated with their consumption?
Ghribi, Feriel; Richir, Jonathan ULiege; Bejaoui, Safa et al

in Environmental Science and Pollution Research (2020)

The current study examined the concentrations of ten trace elements (TE) (nickel, chromium, cadmium, iron, zinc, manganese, aluminum, copper, selenium and lead) in the edible tissue of the Ark shell Arca ... [more ▼]

The current study examined the concentrations of ten trace elements (TE) (nickel, chromium, cadmium, iron, zinc, manganese, aluminum, copper, selenium and lead) in the edible tissue of the Ark shell Arca noae (L. 1758) from a Mediterranean coastal lagoon, the Bizerte lagoon during 2013–2014. The analysis of several redox status biomarkers, metallothioneins (MTs), malondialdehyde (MDA), glutathione peroxidase (GPx), reduced glutathione (GSH) and acetylcholinesterase (AChE), was monitored as a response to TE bioaccumulation and environmental parameters variability. Significant differences (p < 0.05) were observed between mean seasonal TE concentrations in A. noae soft tissue. The highest TE concentrations in A. noae soft tissues were recorded during summer, which coincided with the increase of body dry weight (BDW) and the gonad index (GI). During this season, biomarker responses were enhanced, revealing significant increases of MTs, MDA and GSH levels as well as GPx activity in A. noae tissues, while a decrease of AChE activity was observed. The levels of TE analyzed in A. noae and several parameters used to assess the potential human risk (estimated weekly intake, target hazard quotient and target hazard risk) were lower than the permissible limits for safe seafood consumption. Consequently, this shellfish can be considered safe for human consumption. This preliminary study presents prospects for the valorization of this seafood product in Tunisia’s food sector. It also gives basal information for future environmental assessment studies in which A. noae could be used as early warning tools in the field of biomonitoring programs and confirms the usefulness of biomarkers to monitor the health status of aquatic organisms. [less ▲]

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See detailA 15-Month Survey of Dimethylsulfoniopropionate and Dimethylsulfoxide Content in Posidonia oceanica
Richir, Jonathan ULiege; Champenois, Willy ULiege; Engels, Guyliann et al

in Frontiers in Ecology and Evolution (2020), 7(510), 1-15

Posidonia oceanica is the only reported seagrass to produce significant amount of dimethylsulfoniopropionate (DMSP). It is also the largest known producer of DMSP among coastal and inter-tidal higher ... [more ▼]

Posidonia oceanica is the only reported seagrass to produce significant amount of dimethylsulfoniopropionate (DMSP). It is also the largest known producer of DMSP among coastal and inter-tidal higher plants. Here, we studied (i) the weekly to seasonal variability and the depth variability of DMSP and its related compound dimethylsulfoxide (DMSO) in P. oceanica leaves of a non-disturbed meadow in Corsica, France, (ii) the weekly to seasonal variability and the depth variability of DMSP to DMSO concentration to assess the potential of the DMSP:DMSO ratio as indicator of stress, and (iii) the relationships between DMSP, DMSO, and the DMSP:DMSO ratio with potential explanatory variables such as light, temperature, photosynthetic activity (effective quantum yield of photosystem II), and leaf size. The overall average concentrations of organosulfured compounds in P. oceanica leaves were 130 ± 39 μmol.g−1fw for DMSP and 4.9 ± 2.1 μmol.g−1fw for DMSO. Concentrations of DMSP and DMSO in P. oceanica were overall distinctly higher and exhibited a wider range of variations than other marine primary producers such as Spartina alterniflora, phytoplankton communities, epilithic Cyanobacteria and macroalgae. Concentrations of both DMSP and DMSO in P. oceanica leaves decreased from a maximum in autumn to a minimum in summer; they changed little with depth. Potential explanatory variables except the leaf size, i.e., the leaf age were little or not related to measured concentrations. To explain the seasonal pattern of decreasing concentrations with leaf aging, we hypothesized two putative protection functions of DMSP in young leaves: antioxidant against reactive oxygen species and predator-deterrent. The similar variation of the two molecule concentrations over time and with depth suggested that DMSO content in P. oceanica leaves results from oxidation of DMSP. The DMSP:DMSO ratio remained constant around a mean value of 29.2 ± 9.0 μmol:μmol for the non-disturbed harvested meadow regardless of the time of the year, the depth or the leaf size. As suggested for the salt march plant S. alterniflora, we hypothesized the DMSP:DMSO ratio could be considered as indicator of stress in seagrasses exposed to environmental or anthropogenic stressors. More research would now be needed to confirm the functions of DMSP and DMSO in seagrasses and how the DMSP:DMSO ratio will vary under various disturbances. [less ▲]

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See detailDeep-water Zostera marina meadows in the Mediterranean
Boutahar, Loubna; Espinosa, Free; Richir, Jonathan ULiege et al

in Aquatic Botany (2020), 166

In Morocco, Zostera marina Linnaeus has disappeared from many localities where it was historically reported. The only known remaining meadows along Mediterranean coasts of Morocco, though in North Africa ... [more ▼]

In Morocco, Zostera marina Linnaeus has disappeared from many localities where it was historically reported. The only known remaining meadows along Mediterranean coasts of Morocco, though in North Africa, are those of Belyounech bay and Oued El Mersa bay, in the marine area of ‘Jbel Moussa’. An in-depth knowledge of these meadows is required for their effective conservation purpose. The Z. marina meadows of Jbel Moussa are deep, the lower limit being 17 m depth with patches extending down to 20 m depth. Seagrass cover of Belyounech bay meadow is continuous whereas that of Oued El Mersa is fragmented. Shoot density and aboveground biomass are higher in Belyounech meadow, with 745 ± 183 shoots.m−2 and 273 ± 40 gDW. m−2 of leaf biomass. During the survey, trawling scars and the invasive algae Caulerpa cylindracea Sonder were observed. Bioavailable Ni, As, Mo, Ag, Cd, Sn, Sb and U measured in the sediment are mainly accumulated in Z. marina roots. Nitrogen level is high in seagrass leaves and low in the sediment. Conversely, sediment is more enriched in phosphorus. Carbon levels and its isotopic ratio value are respectively higher and less negative in leaves when compared to the seagrass belowground compartments. All together, data collected during this survey allows defining the overall good health status of Z. marina meadows of Jbel Moussa. These Moroccan meadows, localized within the warm temperate-southern limit of the species, are well developed compared to many places worldwide. The exceptional presence of deep Z. marina meadows in the Mediterranean requires the implementation of measures as a major priority to ensure the conservation of these ecosystems, since seagrasses are being deeply threatened worldwide. [less ▲]

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See detailPosidonia oceanica, a top producer of dimethylsulfoniopropionate and dimethylsulfoxide
Richir, Jonathan ULiege; Champenois, Willy ULiege; Engels, Guyliann et al

in CIESM WORKSHOP MONOGRAPHS (2019, October 10)

We studied the dynamic of dimethylsulfoniopropionate and its derivative dimethylsulfoxide in Posidonia oceanica. The annual average concentrations in leaves were 129 ± 39 μmol.g for DMSP and 5.0 ± 2.1 ... [more ▼]

We studied the dynamic of dimethylsulfoniopropionate and its derivative dimethylsulfoxide in Posidonia oceanica. The annual average concentrations in leaves were 129 ± 39 μmol.g for DMSP and 5.0 ± 2.1 μmol.g for DMSO. DMSP and DMSO concentrations decreased from a maximum in the fall to a minimum in the summer and were mainly correlated to the seagrass leaf size. The similar variation of the two molecule concentrations suggested that DMSO content results from oxidation of DMSP. The DMSP:DMSO ratio, considered as indicator of stress in Spartina alterniflora, remained constant around a mean value of 27.7 μmol:μmol. More research is now needed to investigate the functions of DMSP and DMSO in seagrasses, how the DMSP:DMSO ratio will vary under disturbance and whether it is useful as indicator of stress. [less ▲]

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See detailClimate Change Impact on Water Column in Corsica
Gobert, Sylvie ULiege; Fullgrabe, Lovina ULiege; Quentin, Fontaine et al

in Ozhan E (Ed.) Proceedings of the Fourteenth International Medcoast Congress on coastal and Marine Sciences, engineering, management and Conservatio, (2019, October)

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See detailReproductive cycle and follicle cleaning process of Mytilus galloprovincialis (Mollusca: Bivalvia) from a polluted coastal site in Algeria
Rouabhi, Y. L.; Grosjean, P.; Boutiba, Z. et al

in Invertebrate Reproduction and Development (2019), 63(4),

This work focused on the reproductive cycle and cleaning process of follicles in Mytilus galloprovincialis and aimed to extend knowledge of the reproductive cycles of Mytilidae. Biometric and histological ... [more ▼]

This work focused on the reproductive cycle and cleaning process of follicles in Mytilus galloprovincialis and aimed to extend knowledge of the reproductive cycles of Mytilidae. Biometric and histological measurements were taken monthly over 12 months from mussels at a polluted site, the port of Oran in Algeria. Environmental parameters were monitored concomitantly. Mytilus galloprovincialis reproduced throughout the year, with a main spawning period between November and February and a second between March and June. Several follicle cleaning processes were observed throughout the reproductive cycle. They occurred under two circumstances. First, in the absence of reserve tissues, mature gametes were degraded. This happened when spawning was about to end and corresponded to the last stage of reproduction. Second, atresia, gamete degeneration and a cessation of spawning occurred whatever the stage of the gonad development and whatever the environmental parameter values. These disturbances of reproduction may have resulted from pollution in the port of Oran and increased when temperature exceeded critical thresholds for gametogenesis. To conclude, gamete degeneration and spawning cessation because of coastal pollution and global warming could threaten M. galloprovincialis recruitment, and ultimately the shellfish economy, and could distort biomonitoring strategies using mussels. [less ▲]

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See detailStructural Changes of Seagrass Seascapes Driven by Natural and Anthropogenic Factors: A Multidisciplinary Approach
Abadie, Arnaud ULiege; Richir, Jonathan ULiege; Lejeune, Pierre et al

in Frontiers in Ecology and Evolution (2019), 7

Seascape ecology has been widely applied to marine habitats, including seagrass meadows, through various approaches all over the world for the past 30 years. However, these methods mainly study seagrass ... [more ▼]

Seascape ecology has been widely applied to marine habitats, including seagrass meadows, through various approaches all over the world for the past 30 years. However, these methods mainly study seagrass meadows on a single spatial scale and monitor a single driver of heterogeneity. Additionally, few assess the seascape’s structural evolution. This creates gaps between the scientific data provided and those required by environmental managers and stakeholders in charge of seagrass meadow conservation. To meet their expectations, in this paper we developed a new multidisciplinary approach based on the coupling of mapping techniques, particle flux, and biometric investigations in a Mediterranean Bay, the Calvi Bay (Corsica, France), to assess the structural changes of Posidonia oceanica (L.) Delile meadows subject to disturbances. We focused our investigations on the structural characteristics, the spatial dynamics, and the particle fluxes of natural sand areas generated by bottom currents and dead matte patches which ensued from anchoring damages at 10, 15, and 20m depth. Natural sand patches and anchoring patches differed in size, the first the largest. They also displayed different erosion-colonization dynamics. Natural sand patches were eroded at a mean speed of 12 cm.a−1 and colonized at a rate of 7 cm.a−1. Anchoring patches showed a mean erosion speed of 3.5 cm.a−1 and a colonization rate of 6.5 cm.a−1. Regarding particle fluxes, continuous meadow, and natural patch sedimentation and resuspension rates were 3.7 gDW.m−2.d−1 and 4.1 gDW.m−2.d−1 in average, respectively. In contrast, anchoring patches at 20m depth acted as sediment traps (112.60 gDW.m−2.d−1 in winter) and showed a higher particle resuspension rate. Our results highlighted the dichotomous dynamics of seagrass seascapes influenced by natural and anthropogenic factors. Thus, the smallest anchoring patch will take about 27 years to be recolonized while the biggest requires 60 years to be covered by the plant. With an upscaling approach, together with the newest mapping tools of marine habitats, we suggest a new method to study the evolution of seagrass meadows at a large spatial scale. [less ▲]

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See detailDes indices pour la définition de l’état des masses d’eau en milieu marin : mises au point, applications et aide à la gestion
Gobert, Sylvie ULiege; Richir, Jonathan ULiege

in Geo-Eco-Trop (2019), 43(3), 353-364

Four marine water quality indices have been developed in a reference bay in the Mediterranean: a biological quality index for the European Water Directive (Posidonia Rapid and Easy Index, PREI), an ... [more ▼]

Four marine water quality indices have been developed in a reference bay in the Mediterranean: a biological quality index for the European Water Directive (Posidonia Rapid and Easy Index, PREI), an invasive species colonization index (Indice Caulerpa cylindracea, ICar), a landscape heritage value index (indice Littoral Marin, LIMA) and a pollution index (Trace Element Pollution index, TEPI). These indices have been validated scientifically. The environmental quality they express can be easily visualized by simple codes of colors or combinations of figures-letters positioned on a map. These indices were then applied to larger spatial and/or temporal; their calculation principle can be transposed to other regions and/or ecosystems by setting up reference conditions for the ecosystem, the region investigated. [less ▲]

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See detailBiomonitoring environmental status in semi-enclosed coastal ecosystems using Zostera noltei meadows
Boutahar, L.; Maanan, M.; Bououarour, O. et al

in Ecological Indicators (2019)

Semi enclosed waters, such as estuaries and lagoons, are vulnerable ecosystems that are experiencing persistent trace element (TE) contamination. Seagrasses have been reported worldwide as valuable ... [more ▼]

Semi enclosed waters, such as estuaries and lagoons, are vulnerable ecosystems that are experiencing persistent trace element (TE) contamination. Seagrasses have been reported worldwide as valuable bioindicator species for coastal contamination monitoring purpose. This is, to our knowledge, the first time the TE contamination of semi-enclosed ecosystems has been monitored along the full latitudinal gradient of the Moroccan Atlantic coast. In these ecosystems, the dominant seagrass species is Zostera noltei. 23 TEs (Fe, Al, Cr, Mn, Co, Ni, V, Cu, Zn, Sr, Li, As, Ag, Cd, Sn, Sb, Mo, Ba, Ti, Pb, U, Bi and Hg) and four major elements (Na, Mg, K, Ca) were measured in sediments and seagrass leaf samples were collected upstream and downstream of five semi-enclosed areas. They contrasted in both climatic conditions and levels of environmental contamination. The Trace Element Pollution Index (TEPI) and the Trace Element Spatial Variation Index (TESVI) were calculated from chemical element concentrations in the samples. Of the five semi-enclosed areas, Sidi Moussa lagoon's sediments were the most contaminated (TEPI = 1.18). The TESVI differed highly between chemical elements among the five water bodies for sediments and seagrass leaves, the highest spatial variability being for Ag (TESVI = 72.01 and 21.05 respectively). For Z. noltei leaves, a latitudinal gradient of TE accumulation was recorded. A high bioconcentration factor (BCF > 1) for Cd, Mo, Sb, Ag, Zn and U indicated that the sediments were efficiently uptaken by the seagrass. Significant correlations (p < 0.05) between levels of Cd, Ag, Fe, Al, Ba, Hg, Mn and Zn in sediments and in Z. noltei leaves indicated similar contamination occurrences in both environmental matrices and their bioavailability for seagrasses. Overall, leaf TE bioconcentration among and within the study sites resulted from differences in element bioavailability and environmental conditions (climatic context, hydrological conditions and human impact). Ultimately, Z. noltei is a useful bioindicator of Cd, Mo, Sb, Ag, Zn, U, Al, Fe, Mn, Ba and Hg contamination in sediments. © 2019 Elsevier Ltd [less ▲]

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See detailPAM fluorometry research in Posidonia oceanica
Richir, Jonathan ULiege; Abadie, Arnaud ULiege; Borges, Alberto ULiege et al

Scientific conference (2018, April 26)

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See detailEvolution et variations à long terme du mésozooplancton de la Baie de Calvi
Fullgrabe, Lovina ULiege; Grosjean, Philippe; Richir, Jonathan ULiege

Conference (2018, April 11)

Une série temporelle de 13 ans (2004-2016) du mésozooplancton de la baie de Calvi a été générée en adoptant une approche d’apprentissage supervisée (machine learning). A partir de méthodes d’analyse ... [more ▼]

Une série temporelle de 13 ans (2004-2016) du mésozooplancton de la baie de Calvi a été générée en adoptant une approche d’apprentissage supervisée (machine learning). A partir de méthodes d’analyse d’image et de classification (semi-) automatique, l’abondance mais également le spectre de taille de 14 groupes taxonomiques différents ont pu être déterminés avec un taux de réussite de classification de plus de 90%. L’abondance respective de chacun des groupes est caractérisée par une variation annuelle et/ou interannuelle et différentes corrélations avec des paramètres environnementaux sont soulignées. La caractérisation d’une variation annuelle moyenne par la succession d’ensemble de groupes a permis de décrire une variation interannuelle à l’échelle de communautés. Concernant la variation interannuelle des blooms printaniers, il est mis en évidence que bien que l’intensité du bloom soit corrélée à la température de l’eau, son présence/absence dépend de la concentration en nitrate. Aussi, les périodes et laps de temps caractérisant ces corrélations entre paramètres environnementaux et bloom ont été déterminés. De manière générale, le potentiel contenu dans ces données abondance mais aussi spectre de taille et la biomasse est suggéré. [less ▲]

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See detailContamination par les éléments traces en Méditerranée occidentale, focus sur la baie de Calvi et la Corse. Bilan et perspectives.
Gobert, Sylvie ULiege; Durieux, Eric Dominique Henry; El Idrissi, Ouafa et al

Conference (2018, April 10)

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See detailEtude de la photosynthèse de Posidonia oceanica par fluorimétrie modulée
Richir, Jonathan ULiege; Abadie, Arnaud; Borges, Alberto ULiege et al

Conference (2018, April 10)

Numerous methods for measuring seagrass productivity and growth exist: evolution of O2 or CO2 (incubation chambers, optodes), biomass, shoot leaf elongation, determination of elementary contents … Another ... [more ▼]

Numerous methods for measuring seagrass productivity and growth exist: evolution of O2 or CO2 (incubation chambers, optodes), biomass, shoot leaf elongation, determination of elementary contents … Another possible method relies on pulse amplitude modulation fluorometry (PAM). This technique allows the determination of the photosynthetic quantum yield (Yield) from fluorescence re-emitted by chlorophyll a before and after the application of a saturating light pulse. The Yield determined along a gradient of irradiance draws a light curve (RLC, Rapid Light Curve) similar to photosynthesis-irradiance curves. Since spring 2015 several measurements of Posidonia oceanica photosynthetic activity have been performed at STARESO using diving-PAM fluorometers, for multiple related purposes. The results of these works show that: (i) the absorbance of light by P. oceanica leaves is lower than the average value of terrestrial plants, (ii) the Yield remains constant, being influenced neither by season nor by depth and only the strong light intensities at shallow depths cause its decrease (photoinhibition), (iii) RLCs highlight the high photochemical plasticity of the plant to environmental conditions, (iv) the maximum electron transfer rate modelled from RLCs seems to be a good indicator of the average elongation of shoot leaves and hence of shoot growth and (v) photosynthesis as a biomarker responds to short-term Cu exposures at environmentally relevant levels. Posidonia oceanica photosynthetic activity, which will further be monitored during an in situ shading experiment, is studied in parallel with the development of a new generic biomarker of stress, the ratio of concentrations of organosulfured coumpounds in the plant (dimethylsulfonioproprionate, DMSP and dimethylsulfoxide, DMSO). In conclusion, whether the scientific issue is ecophysiological, environmental, ecotoxicological, PAM fluorometry is a technical approach to consider. [less ▲]

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See detailEtude des séries temporelles : exemple de la température de l’eau
Richir, Jonathan ULiege; Borges, Alberto ULiege; Champenois, Willy ULiege et al

Conference (2018, April 10)

De nombreux paramètres biologiques, environnementaux, climatologiques sont mesurés à et par STARESO depuis des décennies. Les données récoltées sont accessibles via la base de données partagée RACE de ... [more ▼]

De nombreux paramètres biologiques, environnementaux, climatologiques sont mesurés à et par STARESO depuis des décennies. Les données récoltées sont accessibles via la base de données partagée RACE de l’Université de Liège. Dans le cas de séries temporelles, les paramètres suivis sont mesurés de manière séquentielle au cours du temps. La plus représentative est sans aucun doute la série des données de température de l’eau acquise depuis près de 40 ans. La température est un paramètre important qui permet de mettre en évidence sur le long-terme des changements notamment liés au réchauffement climatique, changements qui affectent le fonctionnement des océans tant dans la physique que dans la biologie. L’analyse des séries temporelles de données nécessitent souvent un important travail préparatoire de standardisation (intervalles de mesure irréguliers, trous dans la série, évolution des méthodes d’acquisition des données …). Une fois standardisées, les séries de données peuvent être analysées avec les outils et approches statistiques propres aux séries temporelles : décomposition de la série pour en extraire la tendance générale, statistiques glissantes, calcul des anomalies, analyse des quantiles, mise en évidence d’évènements extrêmes tels les vagues de chaleurs … Tout ce travail, conséquent, doit pouvoir être partagé, vérifié, validé et permettre la mise à jour ultérieure de l’analyse. C’est le concept même de science reproductible. Cette reproductibilité est rendue notamment possible par l’utilisation du langage de programmation R. Cette communication illustre, à travers l’exemple clef de l’évolution de la température de l’eau, l’analyse des séries temporelles de données dans le cadre de STARECAPMED. [less ▲]

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See detailSuivi de la bioaccumulation de métaux traces dans la moule Mytilus galloprovincialis dans la région ouest algérienne
Rouabhi, Yamina Leila; Grosjean, Philippe; Rouane Hassene, Omar et al

Conference (2018, March 21)

L’Algérie est un pays côtier qui n’échappe pas aux pressions anthropiques multiples dont la pollution environnementale liée au développement démesuré de son littoral. Les contaminants notamment issus des ... [more ▼]

L’Algérie est un pays côtier qui n’échappe pas aux pressions anthropiques multiples dont la pollution environnementale liée au développement démesuré de son littoral. Les contaminants notamment issus des rejets urbains, agricoles et industriels impactent de manière croissante les écosystèmes aquatiques algériens. Ainsi, au niveau de la baie d’Oran, près de 80% des eaux usées sont rejetés en mer ou dans les oueds sans traitement préalable. A travers cette étude, nous avons évalué le degré de contamination du littoral algérien par les métaux traces : Zn, Cu, Pb, Fe et Ni. Nous avons réalisé un suivi saisonnier en 2010 de leurs bioaccumulation dans la moule Mytilus galloprovincialis prélevées en deux sites contrastés : le port d’Oran (site contaminé) et Ain Defla (Kristel) (site de référence). Les concentrations en métaux traces ont été mesurées par spectrophotométrie d’absorption atomique dans les branchies et les gonades de moules de 3 à 6 cm et dans des individus entiers (n = 30). Les résultats obtenus montrent que le port d’Oran est un site très contaminé, spécialement pour le Fe, le Zn et le Ni avec des concentrations de l’ordre de 66.57 ± 0.18, 31.31 ± 0.37 et 13.68 ± 0.07 ppm, respectivement dans les deux organes confondus. Les concentrations mesurées à Ain Defla pour ces mêmes métaux sont de 54.48 ± 0.15, 29.52 ± 0.63 et 2.92 ± 0.03 ppm, respectivement. Des différences du même ordre entre les deux sites ont été mesurées également dans les organismes entiers. Seul le Pb présente des concentrations plus élevées dans les branchies des moules prélevées à Ain Defla, soit 3.91 ± 0.29 ppm. Il existe une différence significative (p < 0.05) entre la bioaccumulation des métaux dans les deux organes du site de référence. Ainsi, à Ain Defla, le Fe, le Zn et le Cu sont plus concentrés dans les branchies (46.91 ± 1.60, 25.6 ± 1.07 et 2.68 ± 0.50 ppm, respectivement) que dans les gonades (29.06 ± 1.07, 21.76 ± 1.46 et 1.44 ± 0.20 ppm, respectivement). Dans le site contaminé du port d’Oran, seul le Zn présente des concentrations significativement différentes (p < 0.05) entre les deux tissus, avec des niveaux plus élevés dans les gonades. Chaque métal présente un cycle saisonnier de variation, avec des niveaux élevés durant les saisons hivernales et printanières dans les branchies et la moule entière et durant la saison printanière dans les gonades. La cinétique de bioaccumulation dans les branchies est par ailleurs similaire à celle de l’organisme entier (concentrations plus élevée en hiver) . La forte contamination du port d’Oran par les métaux traces révèle la nécessité d’un suivi écotoxicologique à plus grande échelle du littoral algérien. Or, un tel suivi y est actuellement quasi inexistant. Les branchies jouent un rôle dans la respiration, la filtration et l’excrétion. En tant qu’organe le plus exposé aux contaminants. On lui attribue donc souvent le rôle de tissu le plus approprié pour la biosurveillance. Dans des conditions de fortes contaminations telles que mesurées dans le port d’Oran, les différences tissulaires s’estompent néanmoins. Par ailleurs, M. galloprovincialis étant consommée par les populations locales, le suivi des teneurs en contaminants dans l’organisme entier est une problématique phytosanitaire à considérer. Quant à l’augmentation saisonnière des teneurs en éléments métalliques, elle peut s’expliquer à la fois par des changements de leur biodisponibilité dans le milieu et par le cycle éco physiologique de la moule. Notre étude démontre que M. galloprovincialis se révèle un bioindicateur approprié pour le monitoring de la contamination métallique des côtes algériennes, en prenant soin de normaliser son utilisation (taille, tissu, saison). [less ▲]

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See detailChronic exposure to copper and zinc induces DNA damage in the polychaete Alitta virens and the implications for future toxicity of coastal sites
Watson, G. J.; Pini, J. M.; Richir, Jonathan ULiege

in Environmental Pollution (2018)

Copper and zinc are metals that have been traditionally thought of as past contamination legacies. However, their industrial use is still extensive and current applications (e.g. nanoparticles and ... [more ▼]

Copper and zinc are metals that have been traditionally thought of as past contamination legacies. However, their industrial use is still extensive and current applications (e.g. nanoparticles and antifouling paints) have become additional marine environment delivery routes. Determining a pollutant's genotoxicity is an ecotoxicological priority, but in marine benthic systems putative substances responsible for sediment genotoxicity have rarely been identified. Studies that use sediment as the delivery matrix combined with exposures over life-history relevant timescales are also missing for metals. Here we assess copper and zinc's genotoxicity by exposing the ecologically important polychaete Alitta virens to sediment spiked with environmentally relevant concentrations for 9 months. Target bioavailable sediment and subsequent porewater concentrations reflect the global contamination range for coasts, whilst tissue concentrations, although elevated, were comparable with other polychaetes. Survival generally reduced as concentrations increased, but monthly analyses show that growth was not significantly different between treatments. The differential treatment mortality may have enabled the surviving worms in the high concentration treatments to capture more food thus removing any concentration treatment effects for biomass. Using the alkaline comet assay we confirm that both metals via the sediment are genotoxic at concentrations routinely found in coastal regions and this is supported by elevated DNA damage in worms from field sites. However, combined with the growth data it also highlights the tolerance of A. virens to DNA damage. Finally, using long term (decadal) monitoring data we show stable or increasing sediment concentrations of these metals for many areas. This will potentially mean coastal sediment is a significant mutagenic hazard to the benthic community for decades to come. An urgent reappraisal of the current input sources for these ‘old pollutants’ is, therefore, required. Chronic exposure of zinc and copper via sediment at environmentally relevant concentrations induces DNA damage in a marine polychaete. © 2018 Elsevier Ltd [less ▲]

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See detailMetal bioaccumulation and Oxydatif stress in A. noae.
Ghribi, Feriel; Aouini, Fatma; Bejaoudi, Safa et al

Conference (2017, December)

Detailed reference viewed: 23 (1 ULiège)