In the early 1970s, studies of marine litter first appeared in the scientific literature. Fifty years later, knowledge of several coastal areas of the Atlantic, the driving forces of oyster farmers ...and aquaculture, is lacking. This work documents a pilot study on an Atlantic coastal area (France). This study aims to (i) characterize the abundance of macroplastics related to aquaculture tools; (ii) microplastics present in beach sediments and (iii) characterization of pollutants present on aquaculture plastics collected. First, it was observed that 70% of the plastics collected on the beach were characteristic of aquaculture materials. In sediments, MPs most found were Polyamide between 10 and 20 μm, with a total MP concentration of 397–457 MPs.kg−1. Pipes collectors (PVC), frequently used in aquaculture, have been shown to have concentrations of dimethylphthalates and naphthalene. Waste management and support policies can then base their actions on such studies, in order to improve their knowledge.
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•Significant presence of aquaculture macroplastics on the beach studied•Microplastics found in surface and semi-depth sediments, between 397 and 457 MPs/kg•Polyamide microplastics of 10–20 μm found mainly in beach sediments•Characterization of additives and PAHs on aquaculture plastics•Detection of dimetylphthalate and naphthalene on aquaculture PVC materials
Coral reefs around the world are under threat due to anthropogenic impacts on the environment. It is therefore important to develop methods to monitor the status of the reefs and detect changes in ...the health condition of the corals at an early stage before severe damage occur. In this work, we evaluate underwater hyperspectral imaging as a method to detect changes in health status of both orange and white color morphs of the coral species Lophelia pertusa. Differing health status was achieved by exposing 60 coral samples to the toxic compound 2-methylnaphthalene in concentrations of 0 mg L-1 to 3.5 mg L-1. A machine learning model was utilized to classify corals according to lethal concentration (LC) levels LC5 (5% mortality) and LC25 (25% mortality), solely based on their reflectance spectra. All coral samples were classified to correct concentration group. This is a first step towards developing a remote sensing technique able to assess environmental impact on deep-water coral habitats over larger areas.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Understanding the effects of chronic chemical contamination on natural populations of marine organisms is complex due to the combined effects of different types of pollutants and environmental ...parameters that can modulate the physiological responses to stress. Here, we present the effects of a chronic contamination in a marine bivalve by combining multiple approaches that provide information on individual and population health. We sampled variegated scallops (Mimachlamys varia) at sites characterized by different contaminants and contamination levels to study the short and long-term (intergenerational) responses of this species to physiological stress. We used biomarkers (SOD, MDA, GST, laccase, citrate synthase and phosphatases) as indicators of oxidative stress, immune system alteration, mitochondrial respiration and general metabolism, and measured population genetic diversity at each site. In parallel, concentration of 14 trace metals and 45 organic contaminants (PAHs, PCBs, pesticides) in tissues were measured. Scallops were collected outside and during their reproductive season to investigate temporal variability in contaminant and biomarker levels. Our analyses revealed that the levels of two biomarkers (Laccase-type phenoloxidase and malondialdehyde) were significantly correlated with Cd concentration. Additionally, we observed significant seasonal differences for four of the five biomarkers, which is likely due to the scallop reproductive status at time of sampling. As a source of concern, a location that was identified as a reference site on the basis of inorganic contaminant levels presented the same level of some persistent organic pollutants (DDT and its metabolites) than more impacted sites. Finally, potential long-term effects of heavy metal contamination were observed for variegated scallops as genetic diversity was depressed in the most polluted sites.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
To investigate fungal diversity and biosurfactant-producing fungi in four oil-contaminated sites.
Water and sediment samples were collected from four sites in Brittany (France), over two periods, in ...winter/spring and summer. Fungal diversity was investigated using a metagenetic approach targeting the ITS2 region. Surface-active compound production of 701 fungal isolates collected from these samples after direct plating or following enrichment was assessed using oil spreading and Parafilm M tests. Fungal communities were highly diverse and the main dominant fungal taxa were members of the Cladosporium, Penicillium, Pseudeurotium, Phoma, Aspergillus, and Trichoderma as well as Ochroconis, Fusicolla, and Aureobasidium genera in specific sites. A total of 179 isolates (25.5% of total isolates) were positive to at least one of the screening tests, while 105 were positive to both tests. Major genera among the positive isolates were Fusarium, Trichoderma, Candida, and Penicillium. Six isolates belonging to Aureobasidium pullulans, Mucor griseocyanus, Trichoderma citrinoviride, Trichoderma harzianum, Trichodermalongibrachiatum, and Diaporthe eres showed promising activities.
The present study highlighted the fungal diversity of oil-contaminated environments and the fact that surface-active compound production is widespread in fungi originating from these habitats.
Accidental spills are pervasive pollution in aquatic ecosystems. Resorting to chemical dispersant is one of the most implemented strategies in response to oil spills, but it results in an increase in ...the bio-availability of oil compounds known to disturb fish neurosensory capacities and hence fish habitat use. While it has become well established that acute oil exposure can cause a range of physiological defects, sub-lethal consequences on animal behaviour have only received recent attention. Here we investigated the effect of an exposure to a 62 h- dispersant treated oil on the exploration tendency (exploratory activity, and avoidance of unfamiliar open areas) of juvenile European sea bass. Three different concentrations of chemically dispersed oil were tested, low and medium conditions bracketing the range of likely situations that fish encounter following an oil spill, the high dose representing a more severe condition. Fish recovery capacities were also evaluated during 2 weeks post-exposure. Our results suggest a dose-response relationship; the low dose (0.048 ± 0.007 g L-1 of total petroleum hydrocarbons (TPH)) had no effect on sea bass behavioural response to a novel environment while medium (0.243 ± 0.012 g L-1 TPH) and high (0.902 ± 0.031 g L-1 TPH) doses altered fish exploratory activity and their typical avoidance of unfamiliar open areas. Our experiment also suggest signs of recovery capacities in the first 10 days following oil exposure even if fish might need more time to fully recover from observed alterations. We discuss the possibility that observed alterations may result from a neurosensory or physiological known defects of oil exposure, causing anaesthetic-like sedative behaviours. Altogether, this study shows that juvenile sea bass exposed to oil spill exhibit transient behavioural impairments that may have major population-level consequences given the high mortality experienced by juveniles.
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•Dispersant treated oil exposure affected fish behaviour in a dose-dependent way.•Only the lowest concentration tested did not alter sea bass behaviour.•Fish exposed to high and medium conditions had altered exploratory activity.•Fish spent more time in the central and riskier area of the open field test.•Recovery was observed within 10 days when returned to clean unpolluted seawater.
•Pacific oysters were exposed for 24 days to HDPE microplastics and Chlortoluron.•HFNI valvometry technology allowed both valve activity and daily growth measurements.•Microplastics exposure induced ...an increase of micro-closure frequency•Microplastics exposure induced an decrease of valve opening duration.•Microplastics alone and in a cocktail with chlortoluron reduced the shell growth.
Nowadays, pesticides and microplastics (MPs) are commonly found in coastal waters worldwide. Due to their widespread use, their persistence and toxicity, they may induce adverse effects on physiology and behaviour of marine organisms such as the Pacific oyster (Crassostrea gigas). This study explored the growth and valve activity of juvenile oysters exposed for 24 days to two frequently detected pollutants in the Pertuis Charentais (South West, France): a herbicide (chlortoluron, 85 µg.L−1) and high-density polyethylene microparticles (HDPE 20-25 µm, 112 MP.mL−1) alone or in combination (cocktail condition; 97 µg.L−1 of chlortoluron + 108 MP. mL−1). The valve activity of juvenile oysters recorded by using a High Frequency and Non-Invasive valvometer (HFNI) was characterized by three parameters: the number of valve micro-closures (VMC), the Valve Opening Amplitude (VOA), and the Valve Opening Duration (VOD). Additionally, daily shell growth and the oyster daily rhythm were assessed. The exposure to MPs of oysters led to a significant increase of VMC and a decrease of VOD and shell growth. The exposure to chlortoluron showed a significant increase of VOA and a decrease of VMC. In combination with MPs, chlortoluron still increased VOA and decreased VMC but also reduced the shell growth. Chronobiological analysis did not reveal any effects on the daily rhythm of both contaminants. This work highlighted significant effects of high environmental concentrations of MPs and Chlortoluron on the behaviour and growth of the Pacific oyster.
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Pollution particularly affects coastal ecosystems due to their proximity to anthropic sources. Among those environments, harbours are subjected to marine traffic but also to accidental and chronic ...pollution. These areas are thus exposed to complex mixtures of contaminants such as trace elements and organic contaminants which can impact marine species, habitats, and ecosystem services. The monitoring of these compounds is thus a crucial issue for assessment of environmental health. In this context, the aim of the present work was to evaluate the chemical contamination of harbours in Corsica (NW Mediterranean) by measuring the bioaccumulation of trace elements, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls in mussels, limpets, and sea cucumbers. The human health risks associated with seafood consumption were also assessed. Results reveal a relatively low contamination in the Corsican harbours studied compared to larger Mediterranean ports and suggest that the potential health risk for consumers eating seafood is low.
•Trace elements, PAHs, and PCBs were monitored in Corsican harbours.•The bioindicators considered were native limpets, sea cucumbers, and caged mussels.•Heavy metals, PCBs and PAHs were detected in seafood samples.•The contaminant levels were below their maximum allowable concentrations.•The study suggests low contamination compared to other Mediterranean ports.
Chronic concentrations of polycyclic aromatic hydrocarbons (PAHs) have been commonly detected in international estuaries ecosystems. Reliable indicators still need to be found in order to properly ...assess the impact of PAHs in fish. After an in vivo chronic exposure to hydrocarbons, the enzymatic activity of 7-ethoxyresorufin O-deethylase (EROD) and the antioxidant defense system were assessed in sea bass, Dicentrarchus labrax. A total of 45 fish were exposed to the water-soluble fraction of Arabian crude oil, similar to a complex pollution by hydrocarbons chronically observed in situ, while 45 other control fish sustained the same experimental conditions in clean seawater. Fish samples were made after a 21-day exposure period and after a 15-day recovery period in clean fresh water. Throughout the experiment, liver EROD activity was significantly higher in contaminated fish than in control fish. In addition, nonenzymatic (total glutathione) and enzymatic (GPx, SOD, and CAT) antioxidant defense parameters measured in liver were not significantly different in fish. Furthermore, in gills, glutathione content had significantly increased while SOD activity had significantly decreased in contaminated fish compared to controls. On the other hand, CAT and GPx activities were not affected. Chronic exposure to PAHs disturbing the first step (SOD) and inhibiting the second step (GPx and CAT) could induce oxidative stress in tissues by the formation of oxygen radicals. After the postexposure period, there was no significant difference between control and contaminated fish in any of the antioxidant defense parameters measured in gills, attesting to the reversibility of the effects.
A test program was conducted at laboratory and pilot scale to assess the ability of clays used in drilling mud (calcite, bentonite and barite) to create oil-mineral aggregates and disperse crude oil ...under arctic conditions. Laboratory tests were performed in order to determine the most efficient conditions (type of clay, MOR (Mineral/Oil Ratio), mixing energy) for OMA (Oil Mineral Aggregate) formation. The dispersion rates of four crude oils were assessed at two salinities. Dispersion was characterized in terms of oil concentration in the water column and median OMA size. Calcite appeared to be the best candidate at a MOR of 2:5. High mixing energy was required to initiate OMA formation and low energy was then necessary to prevent the OMAs from resurfacing. Oil dispersion using Corexit 9500 was compared with oil dispersion using mineral fines.
•The ability of mineral fines to create oil-mineral aggregates was investigated under arctic conditions•Four crude oils were tested at laboratory and pilot scale to assess theinfluence of the type of mineral fines, MOR, water salinity on OMA formation•Tests at pilot scale indicated that barite was not a good candidate for OMA formation.•Best results were obtained with calcite, followed by bentonite while barite produced very limited dispersion.•Due to high MOR required to observe oil dispersion, the use of mineralfines could be limited to small spills
Hypoxia and petrogenic hydrocarbon contamination are two anthropogenic stressors that coexist in coastal environments. Although studies have estimated the impact of each stressor separately, few ...investigations have assessed the effects of these stressors in interaction. We therefore investigated the impact of these combined stressors on sea bass, (Dicentrarchus labrax) physiology. After experimental contamination with physically dispersed oil, fish were exposed to hypoxia or normoxia, and active/standard metabolic rates (AMR and SMR, respectively), and metabolic scope (MS) were estimated. At the protocol’s end, the uptake of polycyclic aromatic hydrocarbons (PAHs) was estimated by evaluating relative concentrations of bile metabolites. In terms of bile metabolites, our results validated the uptake of PAHs by contaminated fish in our experimental settings, and further suggest that the hypoxic period after contamination does not reduce or increase compound metabolization processes. Our data showed significant effects of hypoxia on all metabolic rates: a significant drastic AMR reduction and significant SMR diminution led to decreased MS. We also found that oil contamination significantly impacted AMR and MS, but not SMR. These results suggested that when evaluated separately, hypoxia or oil affect the metabolic rate of sea bass. On the other hand, when evaluated in combination, no cumulative effects were observed, since fish exposed to both stressors did not show a stronger impact on metabolism than fish exposed to hypoxia alone. This suggests that oil impacts fish metabolism when fish occupy normoxic waters, and that oil does not magnify hypoxia-induced effects on fish metabolism.
•This study investigates the effects of oil and hypoxia on fish metabolism.•Variables measured were active, standard metabolic rates as well as metabolic scope.•Results revealed an effect of hypoxia on all metabolic variables.•Dispersed oil affected active metabolic rate and metabolic scope.•Combination of both stressors did not induce synergistic nor additive effects
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