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•Plastic particles crossing the intestinal barrier is debated.•PS-NP particles were tested in ex-vivo time series experiments using Ussing chambers.•Two PS-NP concentrations were ...tested on two locations of adult Seabass guts.•PS-NP directly crossed the intestinal barrier of adult Seabass within few minutes.•PS-NP translocation was confirmed by 3 complementary techniques.
Plastic pollution in marine ecosystems constitutes an important threat to marine life. For vertebrates, macro/microplastics can obstruct and/or transit into the airways and digestive tract whereas nanoplastics (NPs; < 1000 nm) have been observed in non-digestive tissues such as the liver and brain. Whether NPs cross the intestinal epithelium to gain access to the blood and internal organs remains controversial, however. Here, we show directly NP translocation across the intestinal barrier of a fish, the European seabass, Dicentrarchus labrax, ex vivo. The luminal side of median and distal segments of intestine were exposed to fluorescent polystyrene NPs (PS-NPs) of 50 nm diameter. PS-NPs that translocated to the serosal side were then detected quantitatively by fluorimetry, and qualitatively by scanning electron microscopy (SEM) and pyrolysis coupled to gas chromatography and high-resolution mass spectrometry (Py-GC-HRMS). Fluorescence intensity on the serosal side increased 15–90 min after PS-NP addition into the luminal side, suggesting that PS-NPs crossed the intestinal barrier; this was confirmed by both SEM and Py-GC-HRMS. This study thus evidenced conclusively that NPs beads translocate across the intestinal epithelium in this marine vertebrate.
Purpose
At the vicinity of metallurgical and steel activities, notable contamination of Potentially Toxic Elements (PTE) is measured in discrete environmental compartments (soils, biosphere, ...atmosphere). The main question addressed in this study pertains to the influence of industrial dust fallout on PTE concentrations in soils. The study was conducted near the seaport of Dunkerque, belonging to one of the most industrialised and dust-emitting sites of France.
Materials and methods
A composite sample of dust fallout was collected over a 4-month-period in urban areas downwind of nearby industries. SEM-EDS and ICP-AES/MS analyses were conducted on this sample to identify metallurgical particles and highlight the main tracer elements of industrial activities. Then, a comprehensive characterization of soils was conducted to map the spatial distribution of metallic pollution levels in the study area. Nearby soil parameters analysis (grain-size distribution, pH, CEC, SOM, calcium carbonates and water contents), the soil chemical composition was identified using XRF and ICP-AES/MS analyses.
Results and discussion
We quantified the proportion of particles of industrial origin in the composite dust sample at 88% of the total fraction, stressing the importance of metallurgical activities near the seaport of Dunkerque. This dust sample shows particularly high enrichment factors (EF) for Cd, Cr, Ni, and Mo with values of 235, 108, 78 and 169 respectively. The use of different pollution assessment indexes evidences that Mo-Cr-Ni associations appear particularly interesting to trace the incorporation of metallurgical sedimentable dusts into soils. Thus, we identified the presence of distinct high-PTE patches related to industrial dust deposition in the studied soils, with a parallel decrease in their quality index (
i.e.
Mo Geo Accumulation Index indicating moderate to heavy contamination).
Conclusions
Our study revealed that the soils located close to the industrial area are the most affected by industrial dust deposition. Several factors explaining the spatial distribution of the soil contamination levels are examined, and it seems that distance from emission sources is not necessarily the most relevant. The study suggests that distribution of plant cover or buildings may act as barriers preventing soils from being exposed to dust deposits.
► Juveniles flounders (5–10cm) were collected in three anthropogenic estuaries. ► Correlations were found between metal contents in sediment and in flounder liver. ► Condition index was lower in fish ...from anthropogenic estuaries than from reference. ► A significant decrease in lipid index was observed in fish from contaminated estuaries. ► Usefulness of metal bioaccumulation and juvenile fish condition combined measures.
Condition indices and metal bioaccumulation of early life stages of juvenile flounder (5–10cm) were determined in three anthropogenic estuaries (the Scheldt, Seine and Loire) and compared to a reference site (the Canche). Significant correlations were found between metal concentrations in sediment and (i) fish liver for Cd, Cu, Ni, Pb, V and Zn and (ii) fish gills for Cd and Mn. Metal accumulation in juvenile flounder from the three anthropogenic estuaries coincided with significantly lower Fulton’s K indices (from 0.99±0.03 to 1.06±0.01mgmm−3) compared to those from the Canche estuary (from 1.02±0.01 to 1.13±0.01mgmm−3). This discrepancy in fish condition index increased with fish size and therefore, strongly depends on the time juvenile spend in estuary. Muscle lipid contents and Triacylglycerol to Sterol ratios were significantly lower in fish collected in the Scheldt (lipid content: 21.3±3.6%), Seine (17.9±19.8%) and Loire (19.5±2.4%) estuaries compared to those originating from the Canche (38.3±4.6%). This study highlights that combined measures of both fish metal contents and condition indices gives a relevant assessment of juvenile fish health growing in anthropogenic estuaries.
The Arctic polychaete,
Oligobrachia haakonmosbiensis
(Family Siboglinidae), is the most abundant symbiotic species inhabiting the Haakon Mosby Mud Volcano (Norwegian Sea, depth 1250 m). Different ...aspects of gametogenesis, fecundity, embryogenesis, and larval development were studied using biometric measurements, classical histology, and scanning electron microscopy on specimens (
n
= 15) collected in July 2009 at two sites (72° 00.28′ N, 14° 43.36′ E; 72° 00.33 ′N, 14° 43.22′ E). Several cohorts of oocytes, from oogonia to mature oocytes were observed in brooding females. Embryos with 16–64 cell divisions, trochophore and metatrochophore larvae, were found, in sequence, in female tubes, from just above the tentacles to the anterior end of the tube. Trochophores had both a prototroch and a telotroch; metatrochophores had an additional ciliary band, the neurotroch, but lacked a down-stream feeding system. All female reproductive stages, oocytes, embryos, and larvae, were recovered in a single specimen suggesting the release of different batches of oocytes at least on the date of collection, which coincided with the boreal summer. Only one brooding female contained exclusively germ cells in the gonad suggesting a pause in reproduction. Fecundity was low: a maximum of 60 mature oocytes per female was counted, and if all the different stages of oocytes, embryos, and larvae were combined, a total fecundity of ~ 250–300 propagules was found in each female. This study advances knowledge of the reproductive biology of
O. haakonmosbiensis
and has particular significance for understanding the distribution of this ecologically important deep-sea chemosymbiotic species in the Arctic region. The new data on life-history traits are critical for modeling, and predicting dispersal potential and connectivity among cold seeps in the Arctic, which is an essential component of marine spatial management.
This study presents an application of the Cytosense flow cytometer (CytoBuoy b.v., NL) for the analysis of the optical properties of phytoplankton cells. For the first time, the forward, sideward and ...backward cross sections (σFSC, σSSC and σ
) were derived for two species morphologically different (Chlamydomonas concordia and Thalassiosira pseudonana). The objective of this work is to check the validity of the estimates before any applications in the frame of marine optics studies. Thus, estimates of σFSC and σSSC are tested with radiative transfer computations as no in situ measurements are available. A synthetic database is built considering homogeneous, multi-layered spheres, aggregates and cylinders. Scanning electron micrographs were performed to investigate the cell morphology to simulate particles as close as possible to the real cells. This set of numerical results represents a valuable database for many kinds of applications dealing with marine optics. Comparisons showed that the Cytosense estimates for the cultures are consistent with values predicted by the theory. In average, more than 92% of the Cytosense estimates were encompassed by predicted values. The backscattering cross section and the backscattering efficiency were compared with in situ measurements found in the literature wherever possible. Results showed that σ
and Q
estimations fall within the range of the referenced values.
Since sediments have the potential to form associations with several classes of pollutants, they have been recognized as a possible and significant source of contamination for the benthic ...environment. Flatfish maintain a close association with sediments for food and cover, and are therefore more likely to be exposed to contaminated sediments, especially in coastal areas (e.g. nursery grounds). The assessment of these potential biological effects involves the use of adapted biomonitoring tools. The main objective of this study was to assess and compare the response of several physiological biomarkers measured on juvenile turbot (
Scophthalmus maximus) exposed to contaminated sediments. Sediments were collected from three stations in a harbour in northern France (Boulogne-sur-Mer), in an anthropogenic French estuary (the Seine), and in a reference site (exposed sandy beach of Wimereux). Unexposed lab-reared juvenile turbots were exposed to sediments for 7 and 21 days in laboratory conditions. Sediments were analysed for metals, PAH and PCB contamination. Several fish growth and condition indices were individually analysed in fish according to the chemical contaminant availability in sediment, the metal concentrations in gills and the estimation of PAH metabolites in their bile. Significant decreases in growth rates, morphometric index, RNA:DNA ratio and the lipid storage index, based on the ratio of the quantity of triacylglycerols on sterols (TAG:ST), were observed with increasing level of chemical contamination. This decrease in the fish's physiological status could be related to the significant increase of several metal concentrations in contaminated fish gills and the significant increase of PAH metabolites in bile. In a field situation, such a reduction in growth and energetic status of juvenile fish could dramatically decrease their over-winter survival in contaminated nursery grounds.
A 45-day exposure experiment was carried out to assess whether the harmful algal blooming Pseudo-nitzschia delicatissima (i.e. needle shaped diatom and potential domoic acid producer) is involved in ...recurrent mass mortality events at a coastal fish farm in the southern North Sea. Juvenile sea bass (Dicentrarchus labrax) were exposed to different concentrations of P. delicatissima, ranging from 1×106 to 5×106cellsL−1. Despite exposure to high concentrations of P. delicatissima, sea bass weight and length based growth rates (0.05±0.02gd−1 and 0.18±0.05mmd−1, respectively) and condition (Fulton K=0.98±0.06mgmm−3) were not significantly reduced suggesting that the fish were not affected during the 45-day exposure period. However, signs of gill mucosa irritation (i.e. mucus overproduction) were observed, showing that this diatom induced a mechanical stress, which can affect gill functions or increase susceptibility of fish to secondary infections (e.g. bacterial and viral infections, parasitism). Results are discussed with regard to consequences for wild and farmed fish, and possible synergic noxious effects when P. delicatissima is associated with other potentially harmful taxa (e.g. Phaeocystis globosa) during the phytoplankton spring bloom in the eastern English Channel–North Sea ecosystem.
•45-day exposure experiment in controlled conditions•Juvenile sea bass exposed to increasing densities of Pseudo-nitzschia delicatissima•P. delicatissima induced a stress response (gill irritation).•P. delicatissima did not impact fish condition and growth.
Field caging experiments were conducted on 0-group juvenile sea bass (Dicentrarchus labrax) and turbot (Scophtalmus maximus) in a polluted area. The fish were caged for 38 days in a northern French ...harbour (Boulogne sur Mer) at three locations with varying levels of contamination. Sediment from each location was analysed for PAHs, PCBs and metal contents, and their respective bioavailability. In the most heavily contaminated station, all the fish died during the two first weeks. At the two other stations, fish recovery was at least 75%. Growth and several health indices were individually measured on the tagged fish and metal bioaccumulation was measured in the fish gills. Juvenile sea bass physiological performance showed significantly higher growth rates, RNA:DNA ratio and Fulton's K condition index in the least contaminated station. The growth in weight and the condition index of the turbot caged in the less contaminated station were also higher. Similarly, for both species, lipid storage index based on the ratio of the quantity of triacylglycerols to sterols (TAG:ST), was significantly higher in the less contaminated station. This general decrease of growth and condition indices, associated with a metal accumulation in gills, reflected the adverse effects of contaminated sediment on the health of the fish. Species-specific responses to chemical contamination were recorded since a stronger relationship between physiological biomarkers and chemical contamination was observed in the sea bass. Therefore, this study supports the use of sea bass as model species and recommends measurements of physiological biomarkers for monitoring complex exposure.
Shallow coastal waters act as nurseries for various fish species and have been recognized as essential fish habitat. We studied heavy metal concentrations in four fish species (plaice, dab, flounder ...and cod) as an indicator of large-scale habitat quality. The study took place along the French coasts between the Eastern English Channel and the Southern Bight of the North Sea.
All species show different concentrations of measured metals (e.g., Cd, Cu, Mn and Pb) in liver but not in muscle. The highest concentrations are found for the flounder and the lowest for cod which is consistent with their habitat and diet. Although our results do not highlight levels of appreciable pollution within the study area, inter-site differences are mainly observed in the muscle tissues and are generally in agreement with the known environmental data (e.g., anthropogenic pressure). However, in the Bay of Seine, one of the most contaminated estuaries in Europe, metal concentrations are in the same range or even lower than those found in fish collected from areas distant from any anthropogenic pressures.
At one site, the comparisons of the Cd, Cu and Pb concentrations between healthy and diseased dabs have been carried out on the muscle and liver tissues. The results of this preliminary study show a relationship between metal concentrations and the pathological status of the fish. The use of fish health as indicator of habitat quality is discussed.
The diversity, toxicity and seasonality of Pseudo-nitzschia sp. were investigated from February to November 2012 in the southern Bight of the North Sea (SBNS) along the French coast. The ...identification of Pseudo-nitzschia species in this area was addressed for the first time in this study. Our results revealed a low species richness (3 distinct species) in association with moderate (102 pg mL−1) to high (263 pg mL−1) domoic acid (DA) levels in autumn and spring, respectively.
Pseudo-nitzschia succession corresponded to the dominance of P. delicatissima in April–May (86% of total diatoms) as a co-occurring species of the Phaeocystis globosa bloom. Following the Phaeocystis bloom (May–September), P. pungens dominated markedly over P. fraudulenta and P. delicatissima and was the only species present in autumn, although at low abundance (<1000 cell L−1). The results of this study support the idea that Pseudo-nitzschia seasonality in the SBNS relies principally on temperature and nutrient availability (DIN and silicates), which, in turn, depend on locally fluctuating environmental conditions (rainfalls and winds). This study highlights the potential for the SBNS to be a potential risk area in regard to the possible impacts of DA on marine resources and the DA transfer through marine food webs. This is of particular concern since DA concentration in seawater was not systematically correlated to potentially toxic Pseudo-nitzschia abundance.
•Low Pseudo-nitzschia sp. diversity (three species) in the southern North Sea.•Domoic acid levels reached 263 pg mL−1 in May 2012, 83% as dissolved DA.•Strong species seasonality driven by temperature and nutrient availability (DIN and silicates).•Autumnal DA concentrations could be attributed to P. pungens.•DA concentration was not systematically correlated to Pseudo-nitzschia spp. abundance.
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