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See detailPOPs in free-ranging pilot whales and sperm whales from the Mediterranean Sea: influence of ecological factors
Pinzone, Marianna ULg; Tasciotti, Aurelie; Ody, Denis et al

Conference (2014, December 13)

The pilot whale Globicephala melas and the sperm whale Physeter macrocephalus are large toothed whales, which permanently inhabit the Northwestern Mediterranean Sea, where they feed mainly on cephalopods ... [more ▼]

The pilot whale Globicephala melas and the sperm whale Physeter macrocephalus are large toothed whales, which permanently inhabit the Northwestern Mediterranean Sea, where they feed mainly on cephalopods. Here they are subjected to numerous anthropogenic threats such as exposure to high levels of contaminants. Selected persistent organic pollutants POPs (29PCBs, 15 organochlorine compounds, 9 PBDEs and 17 PCDD/Fs) were analyzed in blubber biopsies of 49 long-finned pilot whales and 61 sperm whales sampled in NWMS from 2006 to 2013. δ13C, δ15N values and POPs levels were assessed through IR-MS and GC-MS respectively. To assess the toxic potency of the dioxin-like compounds, the TEQ approach was applied. δ15N values were 12.2±1.3‰ for sperm whales and 10.5±0.7‰ for pilot whales, positioning sperm whales at higher trophic levels. δ13C instead was similar and amounted to −17.3±0.4‰ and −17.8±0.3‰ respectively. Pilot whales presented higher concentrations than sperm whales for ΣPCBs (38666±25731ng.g-1 lw and 22849±15566ng.g-1 lw respectively), ΣPBDEs (712±412ng.g-1 lw and 347±173ng.g-1 lw respectively) and ΣDDTs (46081±37506ng.g-1 lw and 37647±38518ng.g-1 lw respectively). Each species was characterized by large inter-individual variations that could probably be more related to sex than trophic level, with males presenting higher contaminant burden than females. The PCA analysis confirmed how p,p’DDT and p,p’DDE were influential in differentiating the two species, as a consequence of their migratory behavior and distribution. Pollutant concentrations of our species were significantly higher than both their Southern Hemisphere and North Atlantic counterparts, possibly due to the particular Mediterranean geomorphology, which influences pollutants distribution and recycle. Dioxin-like PCBs accounted for over 80% of the total TEQ. This study demonstrated (1) an important exposure to pollutants of Mediterranean toothed-whales, often surpassing the estimated threshold toxicity value of 17000ng.g−1 for blubber in marine mammals1; and (2) how the final pollutant burden in these animals is strongly influenced by numerous ecological factors. [less ▲]

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See detailImpact of triclosan on behaviour and neural development of Cyprinodon variegatus
Benichou, Farida; Rahmouni, Chahrazed; Denoël, Mathieu ULg et al

Poster (2014, December 12)

The study focussed on the effects of triclosan (TCS) exposure on mobility and hearing capacities of Cyprinodon variegatus larvae. TCS is an omnipresent antimicrobial and contaminant of aquatic ecosystems ... [more ▼]

The study focussed on the effects of triclosan (TCS) exposure on mobility and hearing capacities of Cyprinodon variegatus larvae. TCS is an omnipresent antimicrobial and contaminant of aquatic ecosystems, which can act as endocrine disruptor, mainly by modifying thyroid functioning. Larval stages are particularly vulnerable to deleterious effects of endocrine disrupters because of potential impairment of fish development and behaviour. Exposure to TCS was conducted at fertilization of eggs at concentrations likely to be found in the environment: 20, 50 and 100 μg.l-1. The analysis of growth parameters of C. variegatus showed no effect of TCS on the fertility of eggs, survival and larval weight. Subsequently, THs concentrations were measured on 15 days post hatching larvae. THs are initially produced as T4 (thyroxine) cells and then converted in the bioactive form of T3 (triiodothyronine) cells. The observed increase of T4 and T3 cells in larvae exposed to 50 and 100 μg.l-1 suggests an increase in THs synthesis as a consequence of TCS exposure. Auditory thresholds of larvae were determined using ABR (Auditory Brainstem Response) technique, and finally larval mobility was measured. For both parameters no significant differences were observed among the three different treatments. Audiograms showed that the auditory system is not yet completely established at 30 days post hatching. However, these results allowed us to consider C. variegatus as an “hearing generalist” because this species have a hearing sensitivity lower than 2000 Hz. Regarding locomotion, our result summarized short time experiences targeting only swimming speed, distance and degree of mobility. It would be interesting to expand the behavioural aspects on other parameters of locomotion and integrate Cyprinodon reaction to different stress (light or touch). In conclusion, our results require an extensive long-term study on the full life cycle of C. variegatus, in order to evaluate the impact of triclosan on neural function and behaviour through several generations. [less ▲]

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See detailSpatial variation in the concentrations of mercury and persistent organic pollutants in free-ranging bottlenose dolphins (Tursiops truncatus) from South Florida
Damseaux, France ULg; Kiszka, Jeremy; Heithaus et al

Poster (2014, December 12)

The bottlenose dolphin (Tursiops truncatus) is an abundant apex predator found in nearshore waters of South Florida, especially in the Lower Florida Keys (Key West) and the coastal waters of Everglades ... [more ▼]

The bottlenose dolphin (Tursiops truncatus) is an abundant apex predator found in nearshore waters of South Florida, especially in the Lower Florida Keys (Key West) and the coastal waters of Everglades National Park (ENP). The objective of this study was to assess variation in contamination levels of total mercury (T-Hg) and persistent organic pollutants (NDL-PCBs, PBDEs, DDT, HCH, HCB, PCDD/Fs and DL-PCBs) in bottlenose dolphins found offshore of the densely populated Key West (n = 27) and from undeveloped ENP (n = 20). T-Hg and POPs were analysed in skin and blubber, respectively, by the mean of Direct Mercury analyser (for THg), GC-ECD (POPs) and GC-HRMS (DLCs). The 7 ICES PCBs were the main compounds found in bottlenose dolphins from Key West (8229 ng.g-1 lipids) and the ENP (2289 ng.g-1 lipids), while the concentrations of PCDD/Fs remained low (Key West: 104 pg.g-1 lipids, ENP: 102 ng.g-1 lipids). POP concentrations were higher in individuals from Key West compared to those from the ENP. However, POPs concentrations in Key West dolphins were lower than those from other locations in Florida and around the world. Unlike organic pollutants, T-Hg concentrations were significantly higher in ENP dolphins (Key West: 2941 ng.g-1 dw versus ENP: 9314 ng.g-1 dw) highlighting the specific cycle of Hg in mangrove ecosystems. To conclude, sources of T-Hg and POPs differed between Key West and ENP as reflected by their concentrations in skin and blubber of free-ranging bottlenose dolphins highlighting their role as sentinels of their environment. [less ▲]

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See detailEvaluation of the impact of Triclosan on the functioning of the thyroid system in Cyprinodon variegatus L., 1803.
Rahmouni, Chahrazed; Benichou, Farida; Klaren, PHM et al

Poster (2014, December)

Triclosan (5-chloro-2-[2, 4-dichlorophenoxy] phenol) is an antimicrobial widely used in various industrial products such as textiles, cosmetics and body care products. It is often detected in aquatic ... [more ▼]

Triclosan (5-chloro-2-[2, 4-dichlorophenoxy] phenol) is an antimicrobial widely used in various industrial products such as textiles, cosmetics and body care products. It is often detected in aquatic environments. The presence of the main biotransformation product, methyl TCS, indicates that this compound is not only degraded, but also persistent and accumulates in aquatic organisms. In this study, the effects of TCS on the thyroid system during embryonic and larval stages in Cyprinodon variegatus were evaluated. In particular, whole body thyroid hormone levels and the activity of deiodinases, enzymes involved in the activation of the thyroid prohormone T4, were measured. Couples of three females and two males were placed in breeding chambers designed for this experiment from which 3832 eggs were obtained by reproduction in the laboratory. Eggs were collected and maintained in seawater. Embryos were selected under a dissection microscope, randomly assigned to each of five treatment groups: Control, DMSO control (vehicle), 20 μg/L TCS, 50 μg/L TCS and 100 μg/L TCS and placed in incubation dishes (50 per dish) at 25°C. On day 6, embryos hatched and larvae were transferred to 1L dishes. The larvae were fed on artemia and on flaked fish food till day 15 post hatching when the fish were analyzed. The fertilization and survival rate, as well as the larval dry weight did not vary significantly between individuals exposed to 20, 50 and 100 μg/L TCS. T3 and T4 concentrations increased significantly in larvae exposed to 50 and 100 μg/L TCS. The study of the activity of enzymes involved in the deiodination of thyroid hormones (ORD) represents a new aspect in the study of endocrine disruption in C. variegatus. Unfortunately, we were not able to detect a net enzymatic T4 deiodination activity, most likely due to the very small amounts of protein and low specific enzyme activity in brain homogenates, carcass and liver. [less ▲]

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See detailThe thyroid gland and thyroid hormones in sheepshead minnow (Cyprinodon variegatus) during early development and metamorphosis
Schnitzler, Joseph ULg; Benichou, Farida; Klaren, PHM et al

Poster (2014, December)

The sheepshead minnow is widely used in ecotoxicological studies that recently, begin to focus on potential disruption of the thyroid axis by xenobiotics and endocrine disrupting compounds. However ... [more ▼]

The sheepshead minnow is widely used in ecotoxicological studies that recently, begin to focus on potential disruption of the thyroid axis by xenobiotics and endocrine disrupting compounds. However, reference levels of thyroxin (T4) and 3,5,3’-triiodothyronine (T3) and their developmental patterns are unknown. This study set out to describe the ontogeny and morphology of the thyroid gland in sheepshead minnow, and correlate these with whole body concentrations of thyroid hormones during early development and metamorphosis. Couples of three females and two males were placed in breeding chambers designed for this experiment. More than 1000 eggs were collected and maintained in seawater. Embryos were selected under a dissection microscope and placed in incubation dishes (50 per dish) at 25°C. On day 6, embryos hatched and larvae were transferred to 1L beakers. For one week after hatching, larvae were fed on artemia, and from 8 to 30 days post-hatch they were fed on flaked fish food. Embryos were sampled on day 0, 3, 6 post-fertilization and larvae and juveniles were sampled every three days from day 0 to 28 days post-hatch. The pooled samples were taken from several incubation dishes and divided in three replicate batches of 10-30 individuals. T4 and T3 were extracted from whole fish bodies and an enzyme-linked immunoassay was used to measure whole-body hormone levels. At each sampling point 5 individuals were placed in formalin fixative for histology. Length and body mass were measured. Hatching success, gross morphology, thyroid hormone levels and histology data were recorded. The onset of metamorphosis at 12 days post-hatching coincided with surges in whole body T4 and T3 concentrations. Thyroid follicles were first observed in pre-metamorphic larvae at hatching, and were detected exclusively in the subpharyngeal region, surrounding the ventral aorta. Follicle size and epithelial cell heights varied during the developmental phase, indicating fluctuations in thyroid hormone synthesis activity. The increase in the whole body T3/T4 ratio was indicative of an increase in outer ring deiodination. This study establishes a baseline for thyroid hormones in sheepshead minnows, which will be vital for the understanding of thyroid hormone functions and in future studies of thyroid toxicants in this species. [less ▲]

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See detailThe effects of Triclosan on the metabolism of developing Sheepshead minnow (Cyprinodon variegatus) larvae
Lallemand, Lise; Voisin, Anne-Sophie; Darchambeau, François ULg et al

Poster (2014, December)

The aquatic environment represents the final sink for many chemicals, including bactericidal agents. Among them Triclosan (TCS) has been shown to affect the thyroid system of teleost. Thyroid hormones are ... [more ▼]

The aquatic environment represents the final sink for many chemicals, including bactericidal agents. Among them Triclosan (TCS) has been shown to affect the thyroid system of teleost. Thyroid hormones are involved in the control of metabolism, so changes in hormone levels induced by triclosan may affect respiratory rates and antioxidant stress in exposed fish. Couples of three females and two males were placed in breeding chambers designed for this experiment. Eggs were collected and maintained in seawater. Embryos were selected under a dissection microscope, randomly assigned to each of five treatment groups: Control, DMSO control, 20 μg/L TCS, 50 μg/L TCS and 100 μg/L TCS and placed in incubation dishes (50 per dish) at 25°C. On day 6, embryos hatched and larvae were transferred to 1L dishes. The larvae were fed on artemias and on flaked fish food till day 15 and 30 post hatching when the fish were analyzed. Respiratory rate measurements were carried out by respirometry and assays of antioxidant enzymes, Glutathionreductase (GR), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) were conducted to determine the presence of oxidative stress. Respirometry showed that TCS exposed fish exhibited decreased the metabolism at 15 dph, whereas no differences in respiration rate could be observed between control and exposed larvae at 30 dph. At 15 dph no difference was observed for any of the antioxidant enzymes, whereas at 30 dph a sharp increase in the activity of GR was observed between the control and TCS exposed fish. The activity of GST and Gpx remained stable. Thyroid hormones are major factors controlling the metabolic rate related to respiration and oxidative stress. TCS reduced the metabolism at 15 dph that corresponds to the moment where larvae to juvenile transition of Sheepshead minnows occur. Previous experiments showed that TCS induces an increase in thyroid hormone concentrations and hyperthyroidism induces oxidative stress. So our observed increase of antioxidant protection mechanisms could be a way to compensate oxidative stress. On the other hand, the changes in GR activity observed at 30 dph, may also be related to the reduced metabolism at 15 dph. [less ▲]

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See detailHarbour seals as sentinels for the marine environment
Das, Krishna ULg

Scientific conference (2014, November 25)

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See detailSeals as sentinels for the marine environment
Das, Krishna ULg

Scientific conference (2014, November 25)

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See detailApplications of stable isotopes in trophic ecology and ecotoxicology
Lepoint, Gilles ULg; Remy, François ULg; Michel, Loïc ULg et al

Scientific conference (2014, September 19)

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See detailDiscrimination of two geographically distinct populations of sea bass Dicentrarchus labrax, using stable isotopic signatures of mercury (δ202Hg, Δ199Hg)
Cransveld, Alice ULg; Amouroux, David; Koutrakis, Emmanuil et al

Poster (2014, May 15)

Despite the reduction of mercury (Hg) emissions in Europe in the last decades, Hg emissions are increasing worldwide and concentrations found in some marine predators remain high. This raises questions on ... [more ▼]

Despite the reduction of mercury (Hg) emissions in Europe in the last decades, Hg emissions are increasing worldwide and concentrations found in some marine predators remain high. This raises questions on mercury's biogeochemical cycle at both local and global scale. In the present work, we investigate the possibility to use mercury isotopic signature in fish as a tool to discriminate different polluted areas and potential pollution sources. Indeed, Hg can exhibit both mass-dependent (MDF) and mass-independent fractionation (MIF). While MDF may occur during biological cycling inter alia and could be used to understand bioaccumulation processes, MIF provides a unique fingerprint of specific chemical pathways, such as photochemical transformations. In this context, information provided by Hg isotopes would help to improve environmental management strategies. A preliminary set of four and ten juvenile common sea bass, Dicentrarchus labrax were collected from the North Sea and the Aegean Sea respectively. T-Hg was analysed by direct mercury analyser (DMA), speciation by gas chromatography inductively coupled plasma mass spectrometer (GC-ICP-MS) and Hg isotope analysis were performed using cold vapour generation with multicollector ICP-MS. Total Hg concentrations in all tissues were higher in individuals from the North Sea ( Hgtot muscle=1,14 ± 0,48 mg.kg-1 dw) than from Greece (0,60 ± 0,06 mg.kg-1 dw). Speciation analysis shows that MeHg is the predominant form of Hg in muscle (89% MeHg on average) but not in liver (51% MeHg on average). Isotopic mass dependent values (δ202Hg) values were always higher in muscle than in liver and related to Hg species distribution. For mass independent isotopic signature, sea bass from the Aegean Sea had a systematically higher Δ199Hg value than individuals from the North sea (e.g.: 0,56 ± 0,05‰ and 0,32 ± 0,06‰ respectively in muscle). While mass dependent isotopic signature probably reflects some internal Hg metabolism, mass independent isotopic signature seems definitely site dependent. Such isotopic discrimination might be in agreement with difference in both mercury sources and cycling in the North and Aegean Seas. These preliminary results indicate that Hg isotopes may thus help to discriminate fish from different areas. This promising outcome must be further confirmed by extending the number of individuals and locations to be investigated. [less ▲]

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See detailMicroplastics contamination in two planktivorous and commercial fish species
Collard, France ULg; Parmentier, Eric ULg; Das, Krishna ULg

Poster (2014, May 13)

Plastic pollution is a huge environmental concern and affects each marine ecosystem. Plastics are produced by millions of tonnes each year in the world and finally accumulate in oceans. They adsorb many ... [more ▼]

Plastic pollution is a huge environmental concern and affects each marine ecosystem. Plastics are produced by millions of tonnes each year in the world and finally accumulate in oceans. They adsorb many persistent organic pollutants, cause external and internal wounds and provoke blockage of the digestive tract of marine mammals, birds and turtles. Plastics can also threaten marine organisms of small size class in the same way by fragmenting in smaller parts that result in microplastics of less than five millimetres. These microplastics are of the same order of magnitude than plankton and can thus be ingested by filter-feeders, suspension-filters and planktivorous organisms such as fish. Few studies deal with microplastics ingestion by fish and even less by commercial fish species. The herring (Clupea harengus) and the sardine (Sardina pilchardus) were respectively the third and the eighth most caught fish species in the world in 2009. We focused our research on these two species which are of economic importance. We sampled around thirty individuals of each species in the Channel and in the North Sea in January 2013. The stomach contents were digested by sodium hypochlorite and then analyzed. Microplastics were characterized by size, colour and shape. The results of these analyses will highlight the need for studies about microplastics ingestion by planktivorous species. [less ▲]

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See detailHabitat use of a population of bottlenose dolphins, Tursiops truncatus gephyreus, analyzed by means of Kernel Density Estimation (KDE) method
Cransveld, Alice ULg; Denoël, Mathieu ULg; Das, Krishna ULg et al

Poster (2014, April 09)

The San Antonio Bay (SAB), in Patagonia, Argentina, harbors a resident population of bottlenose dolphins (Tursiops truncatus gephyreus). It seems a privileged area to give birth and nurse calves. In the ... [more ▼]

The San Antonio Bay (SAB), in Patagonia, Argentina, harbors a resident population of bottlenose dolphins (Tursiops truncatus gephyreus). It seems a privileged area to give birth and nurse calves. In the context of declining populations worldwide and more particularly in South America, preserving the SAB population takes a considerable significance. Yet the SAB is facing human population growth and touristic development, which represent potential threats for the dolphin population, especially dolphin-watching activities. In this context, the aim of this study was to understand the bottlenose dolphin’s habitat use within the bay, and to consider how this information could be used in prospective management strategies. Particularly, we aimed at using the Kernel Density Estimation (KDE) method to map the intensity of space use for essential behavioural patterns. To this end, we collected behavioural information on dolphins during 25 boat-based surveys in the bay in 2011. The habitat use of the bay was heterogeneous: some areas were more intensely used than others. Dolphins spent most of their time traveling and diving. Variables associated to resting behaviours, e.g. school size and depth, indicated that the SAB would be a safer place compared to other known residency areas, confirming its suitability for conservation purposes. KDE analyses showed that behaviours are not evenly distributed inside the bay. Bottlenose dolphins being more sensitive to anthropogenic disturbances while engaged in resting or socializing behaviours, it is crucial to locate these behaviours. In SAB, the KDE shows that resting and socializing areas are located in the Northern part of the bay, indicating that it should constitute a priority protected area in potential future management strategies. Furthermore, our results show that the KDE method is an appropriate and advantageous tool when determining critical habitats, worth being more widely used. [less ▲]

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See detailMicroplastics caught in herring gill rakers: illustration by scanning electron microscopy
Collard, France ULg; Das, Krishna ULg; Parmentier, Eric ULg

Conference (2014, March 07)

Plastics are produced in huge quantity (280 million of tons in 2012) and more than 10% end up in the oceans. It is estimated that between 60 and 80% of all marine debris are plastics. Plastics are ... [more ▼]

Plastics are produced in huge quantity (280 million of tons in 2012) and more than 10% end up in the oceans. It is estimated that between 60 and 80% of all marine debris are plastics. Plastics are persistent and have accumulated in the oceans for several decades. Plastics may adverse wildlife in many ways: they can be ingested by marine vertebrates and cause internal wounds in the digestive tract. Plastics are also vectors of organic pollutants including. Once ingested, plastics may release these pollutants in the organism. Plastics present in the marine environment fragment in small pieces by mechanical stress and UV radiation leading to the so-called microplastics smaller than 5 mm. Little is known about microplastics ingestion and toxicity in planktivorous fish such as the herring, Clupea harengus. Planktivorous fish have gill rakers, which may function as a trap for microplastics. This study aims to describe and characterise microplastics present on gill rakers of the herring, Clupea harengus. Ten gill cavities were sampled in January 2013 in the Channel and the North Sea during a fishery campaign organized by the IFREMER. Gills cavities were placed in a fixating solution until preparation for scanning electron microscopy (SEM). SEM was used in order to detect microplastics which are too small to be observed by a dissection microscope, to compare them with the distance between gill rakers and to characterise the surface and the shape of microplastics. Scanning electron microscopy revealed large variety of microplastics, which lengths ranged from 0.05 to 5mm. Relationship between microplastics length and distance between gill rakers was analysed on the same branchial arch. The present study revealed the presence of microplastics in an edible species of high economic value and raise question about potential impact on the herring and its consumers, including human beings. [less ▲]

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See detailUsing features of mercury and methylmercury to discriminate contamination profiles between sea bass, Dicentrarchus labrax, populations
Cransveld, Alice ULg; Amouroux, David; Koutrakis, Emmanuil et al

Poster (2014, March 07)

Despite many efforts consented in the last decades, Mercury (Hg) emissions have kept rising worldwide. Currently, anthropogenic inputs dominate Hg emissions to the atmosphere by far, natural releases ... [more ▼]

Despite many efforts consented in the last decades, Mercury (Hg) emissions have kept rising worldwide. Currently, anthropogenic inputs dominate Hg emissions to the atmosphere by far, natural releases accounting only for a 4th of the total. Because Hg has a stable gaseous form (Hg0) with a long residence time in the atmosphere (~1year), both natural and industrially produced Hg can be transported far from point sources. Therefore, many uncertainties remain in our knowledge about Hg biogeochemistry. Our study aims at identifying the different Hg forms found in marine predators in order to discriminate different polluted areas and potential pollution sources. More specifically, we seek to discriminate contaminations of local origins versus contamination of global origins. To achieve this, we are currently studying different sea bass, Dicentrarchus labrax, populations from the Atlantic Ocean and Mediterranean. In muscle, liver, kidney and brain tissues, we analyze total Mercury (THg) and methylmercury (MeHg). We are also testing the discrimination power of Hg's stable isotopes (199Hg, 201Hg and 202Hg). Indeed, recent findings show that Hg isotopes can exhibit both mass-dependent (MDF) and mass-independent fractionation (MIF). This means that Hg isotopes provide two different types of information at once, both on biological cycling of Hg, including bioaccumulation (MDF), and on chemical pathways such as photochemical transformations (MIF). Eventually, we are planning to extend our results with compound specific isotope analysis (CSIA) on the carbon of methylmercury. Preliminary analysis performed on 14 juvenile specimens from the North Sea and the Aegean Sea indicate that THg concentrations are higher in individuals from the North Sea than from Greece. The lack of correlation with size and weight indicate that it is likely linked to a difference in contamination levels between the two areas. MeHg is the predominant form of Hg in muscle, while the same cannot be asserted for liver. Mass dependent isotopic values (δ202Hg), were always higher in muscle than in liver and, for each tissue, values were similar between the two areas. This is probably related to the species distribution and to some internal Hg metabolism. For mass independent isotopic signature (MIF), sea bass from the Aegean Sea had a systematically higher Δ201Hg value than individuals from the North Sea. Thus, mass independent values seem definitely site dependent and might be in agreement with differences in both mercury sources and cycling in the North and Aegean Seas. These preliminary results consequently indicate that Hg isotopes may help to discriminate fish from different areas. This promising outcome must be further confirmed by extending our sampling and will be coupled to other results obtained through CSIA. [less ▲]

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See detailMetallothioneins pattern during ontogeny of coastal dolphin, Pontoporia blainvillei, from Argentina
Polizzi, P.S.; Romero, M.B.; Chiodi Boudet, L.N. et al

in Marine Pollution Bulletin (2014)

Metallothioneins are signals of metal exposure and widely used in biomonitoring. Franciscana dolphin is an endemic cetacean from the Southwestern Atlantic Ocean, classified as Vulnerable A3d by the IUCN ... [more ▼]

Metallothioneins are signals of metal exposure and widely used in biomonitoring. Franciscana dolphin is an endemic cetacean from the Southwestern Atlantic Ocean, classified as Vulnerable A3d by the IUCN. Metallothionein, copper and zinc in Franciscana were assessed in two geographic groups; one inhabits La Plata River estuary, anthropogenically impacted, and the other inhabits marine coastal ecosystems, with negligible pollution. Despite the environment, hepatic and renal MT concentrations were similar, but there was a declining trend from early to later developmental stages. Metallothionein K/L, Cu and Zn levels corresponded to normal reported ranges. MT was not related with Cd. Fetal concentrations were higher than its mother. These results and the health status of dolphins are suggesting that MT correspond to physiological ranges for the species, and they are closely to homeostasis of Zn and Cu, according to its ontogenetic changes. The information constitutes the first MT information on Franciscana dolphin and can be considered as baseline for the species conservation. [less ▲]

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See detailUSING TOP PREDATORS AND DR-CALUX TO SCREEN COASTAL ENVIRONMENTS FROM THREE DIFFERENT BRAZILIAN REGIONS FOR DIOXINS AND RELATED COMPOUNDS
Dorneles; Lailson-Brito; Bisi et al

in Organohalogen Compounds (2014), 76

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See detailMobilisation of lipophilic pollutants from blubber in northern elephant seal pups (Mirounga angustirostris) during the post-weaning fast
Louis, Caroline; Dirtu, Alin C.; Stas, Marie et al

in Environmental Research (2014), 132

Northern elephant seals (NES) (Mirounga angustirostris) from the Año Nuevo State Reserve (CA, USA) were longitudinally sampled during the post-weaning fast in order to study the mobilisation and ... [more ▼]

Northern elephant seals (NES) (Mirounga angustirostris) from the Año Nuevo State Reserve (CA, USA) were longitudinally sampled during the post-weaning fast in order to study the mobilisation and redistribution of various classes of persistent organic pollutants (POPs), such as polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (p,p′-DDE) and hexachlorobenzene (HCB) between blubber and blood. Inner and outer blubber layers were analysed separately. Organohalogenated compounds were detected in all blubber samples in the decreasing order of their concentrations: p,p′-DDE>PCBs⪢HCB>PBDEs. The concentrations of all studied compounds were homogeneously distributed in the blubber layer at early fast, since the concentrations of POPs were statistically not different in the inner and outer layers. With the progression of the fast, the concentrations of PBDEs, PCBs and p,p′-DDE increased more sharply in inner blubber than in outer blubber. As a result, their levels became significantly higher in inner blubber as compared to outer blubber at late fast. The rise of pollutant concentrations in blubber might result from a less efficient mobilisation than triglycerides and/or a reuptake by adipocytes of some of the pollutants released into the circulation. The mobilisation of pollutants from blubber was higher at late fast. An increase of pollutant concentrations was observed in serum between early and late fast. Lower halogenated congeners (i.e. tetra-CBs) were present in higher proportions in serum, whereas the higher halogenated congeners (i.e. hepta-CBs) were mainly found in the inner and outer blubber layers. The transfer ratios of both PBDEs and PCBs from inner blubber to serum decreased with the number of chlorine and bromine atoms. In addition, the distribution of both types of compounds between serum and blubber was strongly influenced by their lipophilic character (log Kow values), with more lipophilic compounds being less efficiently released from blubber to serum. [less ▲]

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See detailTrophic Relationships and Habitat Preferences of Delphinids from the Southeastern Brazilian Coast Determined by Carbon and Nitrogen Stable Isotope Composition
Bisi, Tatiana; Dorneles, Paulo; Lailson-Brito, José et al

in PLoS ONE (2013), 8(12),

To investigate the foraging habitats of delphinids in southeastern Brazil, we analyzed stable carbon (δ13C) and nitrogen (δ15N) isotopes in muscle samples of the following 10 delphinid species: Sotalia ... [more ▼]

To investigate the foraging habitats of delphinids in southeastern Brazil, we analyzed stable carbon (δ13C) and nitrogen (δ15N) isotopes in muscle samples of the following 10 delphinid species: Sotalia guianensis, Stenella frontalis, Tursiops truncatus, Steno bredanensis, Pseudorca crassidens, Delphinus sp., Lagenodelphis hosei, Stenella attenuata, Stenella longirostris and Grampus griseus. We also compared the δ13C and δ15N values among four populations of S. guianensis. Variation in carbon isotope results from coast to ocean indicated that there was a significant decrease in δ13C values from estuarine dolphins to oceanic species. S. guianensis from Guanabara Bay had the highest mean δ13C value, while oceanic species showed significantly lower δ13C values. The highest δ15N values were observed for P. crassidens and T. truncatus, suggesting that these species occupy the highest trophic position among the delphinids studied here. The oceanic species S. attenuata, G. griseus and L. hosei had the lowest δ15N values. Stable isotope analysis showed that the three populations of S. guianensis in coastal bays had different δ13C values, but similar δ15N results. Guiana dolphins from Sepetiba and Ilha Grande bays had different foraging habitat, with specimens from Ilha Grande showing more negative δ13C values. This study provides further information on the feeding ecology of delphinids occurring in southeastern Brazil, with evidence of distinctive foraging habitats and the occupation of different ecological niches by these species in the study area. [less ▲]

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See detailSeals as sentinel species for the marine environment
Das, Krishna ULg

Conference (2013, October)

Detailed reference viewed: 24 (3 ULg)
Peer Reviewed
See detailDevelopment of an analytical strategy to measure major selenium-containing species in juvenile turtles (Trachemys scripta scripta) by SAX-HPLC-ICP MS
Far, Johann ULg; Dyc, Christelle; Das, Krishna ULg et al

Poster (2013, July)

Sea turtles are exposed to many environmental elements such as selenium (Se). Sea turtles are listed under the Red List of threatened species by the International Union for Conservation of Nature. It is ... [more ▼]

Sea turtles are exposed to many environmental elements such as selenium (Se). Sea turtles are listed under the Red List of threatened species by the International Union for Conservation of Nature. It is thus mandatory to use low-invasive tissue collection (skin, carapace, blood ) for estimating Se exposure in these highly protected turtles. For this purpose, a biological modal Trachemys scripta scripta (or slider turtle) was selected. For two months, juvenile turtles were dietary exposed to Se by spiking the food with Selenomethionine (SeMet) or Methionine as control groups. Individuals were sacrificed after different time of exposure and tissues (skin, liver, muscle, carapace and blood) collected to perform Se speciation and determine some biological endpoints. An analytical strategy was developed to cope with the very low amount of available sample. It is briefly consisting by reduction, alkylation and proteolysis of the entire freeze-dried tissues followed by sample clean-up using ultra-filtration membrane. Then anion exchange HPLC using salt and pH gradient was developed to prevent the introduction of organic solvents, which cause severe fooling of ICP MS and avoid ultra-trace analyses of sea water in routine analysis. This method successfully achieved the detection and quantification at ppm level of expected species (i.e SeMet, selenocysteine, inorganic Se) and also unknown species but their relative amounts were time and tissues dependent. [less ▲]

Detailed reference viewed: 59 (2 ULg)