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Ocean acidification (OA) resulting from anthropogenic emissions of carbon dioxide (CO(2)) has already lowered and is predicted to further lower surface ocean pH. There is a particular need to study effects of OA on organisms living in cold-water environments due to the higher solubility of CO(2) at lower temperatures. Mussel larvae (Mytilus edulis) and shrimp larvae (Pandalus borealis) were kept under an ocean acidification scenario predicted for the year 2100 (pH 7.6) and compared against identical batches of organisms held under the current oceanic pH of 8.1, which acted as a control. The temperature was held at a constant 10°C in the mussel experiment and at 5°C in the shrimp experiment. There was no marked effect on fertilization success, development time, or abnormality to the D-shell stage, or on feeding of mussel larvae in the low-pH (pH 7.6) treatment. Mytilus edulis larvae were still able to develop a shell in seawater undersaturated with respect to aragonite (a mineral form of CaCO(3)), but the size of low-pH larvae was significantly smaller than in the control. After 2 mo of exposure the mussels were 28% smaller in the pH 7.6 treatment than in the control. The experiment with Pandalus borealis larvae ran from 1 through 35 days post hatch. Survival of shrimp larvae was not reduced after 5 wk of exposure to pH 7.6, but a significant delay in zoeal progression (development time) was observed.

The sensitivity of different tissues for assessment of chronic low-dose environmental exposure of fish to alkylphenols (APs) was investigated. We exposed Atlantic cod (Gadus morhua) in the laboratory to tritium labelled 4-tert-butylphenol, 4n-pentylphenol, 4n-hexylphenol, and 4n-heptylphenol via seawater (8 ng/l) and via contaminated feed (5 microg/kg fish per day). Measurements of different fish tissues during eight days of exposure and eight subsequent days of recovery revealed that APs administered via spiked seawater were readily taken up whereas the uptake was far less efficient when APs were administered in spiked feed. AP residues were mainly located in the bile fluid whereas the concentrations in liver were very low, indicating a rapid excretion and the liver-bile axis to be the major route of elimination. The biological half-life of APs in the exposed cod was short, between 10 and 20 h. Our study shows that in connection with biomonitoring of AP exposure in fish, assessment of AP metabolites in bile fluid is a more sensitive tool than detection of parent AP levels in liver or other internal tissues.

Despite the extensive transport of chemicals at sea, there is current lack of knowledge of the fate and effects of many of them on the marine biota. The current regulation that follows the GESAMP-MARPOL classification is mainly based on ecotoxicity assessment from fresh water based studies. Repetitive spills in marine coastal environment from tanker ship loaded with several thousand tonnes of chemicals raised concern about whether the existing freshwater data location can be used to predict the behaviour and the environmental effects of contaminants in marine surroundings. There is a general lack of information of the fate of chemicals at sea. A deviating pattern in marine environment from that in freshwater may have significant consequences for the counteracting actions taken to fight the spill, on staff working on the site of spill as well as on marine life present in the vicinity of the accident. In the present article, an environmental effect study of styrene was conducted as part of the ECOPEL program. We report some biological effects of styrene in laboratory-exposed marine organisms. Styrene was continuously supplied at a nominal concentration of 2mg L(-1) over 7 days to both mussels (Mytilus edulis) and fish (Symphodus mellops). At the end of this period, DNA damage was assessed by the Comet assay performed on blood (fish) and haemolymph (mussel) cells. In mussels, the lysosomal membrane stability was additionally assessed by the neutral red retention time assay (NRRT). Significant biological responses were observed over the studied period in both organisms with these two tests. Hence, the results favour the use of a biomarker-based approach to assess the health conditions in case of spill.

Sheepshead minnows (Cyprinodon variegatus) were continuously exposed to two concentrations of polycyclic aromatic hydrocarbons (PAHs) dissolved in seawater (Σ PAH 5 7.57 and 72.31 µg/L) for 36 d, followed by 8 d of depuration. The PAHs studied were naphthalene (NPH or C0-NPH), phenanthrene (PHE or C0-PHE), pyrene (PYR), 2-methylnaphthalene (C1-NPH), 1,3-dimethylnaphthalene (C2-NPH), 2-isopropylnaphthalene (C3-NPH), 9-methylphenanthrene (C1-PHE), and 9-ethylphenanthrene (C2-PHE). Uptake rate constants (k1 ) for NPHs increased with increasing degree of alkylation and log value of the octanol/water partition coefficient (Kow), whereas k1 values for three- and four-ring PAHs were lower despite their high log Kow values. Elimination rate constants (k2) for the homologue series of NPHs and PHEs generally increased with decreasing degree of alkylation and log Kow values. However, the depuration time did not directly correlate with the molecular size for nonalkylated PAHs. Bioconcentration factors (BCFs) were estimated from the ratio of k1 to k2 and also directly from PAH concentrations in fish tissue and water samples, and the factors generated by the two methods were very similar. A significant positive correlation was determined between log BCFs and log Kow values for the series of C0 - through C3-NPH at both low (r² = 0.985, p = 0.0077) and high (r² = 0.956, p = 0.022) exposures, although this correlation was not determined for all the PAHs studied. As a result of increased metabolism and/ or reduced bioavailability with increasing lipophilic character, the estimated BCFs for C0 - through C2-PHE and PYR were generally lower than those for C0- through C3-NPH. The two exposure levels revealed minor variations... [ABSTRACT FROM AUTHOR]

In situ burning (ISB) is an oil spill clean-up option used by oil spill responders to mitigate impacts on the marine environment. Despite advantages such as high efficiency and potential applicability for challenging areas such as the Arctic, the actual environmental side effects are still uncertain. Acute and sublethal effects of the water accommodated fractions (WAFs from 25 g oil/L seawater) of a pre-weathered North Sea crude (Oseberg Blend 200 °C+) and field generated ISB residue were evaluated on Northern shrimp (Pandalus borealis) larvae. The larvae were first exposed for 96 h to a serial dilution of seven concentrations, and then maintained for two weeks in clean seawater post-exposure. No acute (mortality) or sublethal effects (feeding, development, or growth) were detected in any of the ISB residue concentrations. Significant larvae mortality was found in the three highest concentrations of crude oil (96-h LC50:469 μg/L total petroleum hydrocarbon) but no sublethal effects were found in the surviving larvae post-exposure. This study indicates that applying ISB could mitigate acute impacts of spilled oil on shrimp larvae. [Display omitted] • Comparative toxicity of crude oil and in situ burn residue in shrimp larvae. • Crude oil exposure caused mortality but no sublethal effects. • No acute nor long-term effects found after exposure to the in situ burn residue. • Important contribution to Spill Impact Mitigation Assessment. [ABSTRACT FROM AUTHOR]

In this paper, a molecular analytical approach for detecting hydrocarbonoclastic bacteria in water is suggested as a proxy measurement for tracking petroleum discharges in industrialized or pristine aquatic environments. This approach is tested for general application in cold marine regions (freezing to 5 °C). We used amplicon sequencing and qPCR to quantify 16S rRNA and GyrB genes from oleophilic bacteria in seawater samples from two different crude oil enrichments. The first experiment was conducted in a controlled environment using laboratory conditions and natural North Sea fjord seawater (NSC) at a constant temperature of 5 °C. The second was performed in the field with natural Arctic seawater (ARC) and outdoor temperature conditions from −7 °C to around 4 °C. Although the experimental conditions for NSC and ARC differed, the temporal changes in bacterial communities were comparable and reflected oil biotransformation processes. The common bacterial OTUs for NSC and ARC had the highest identity to Colwellia rossensis and Oleispira antarctica rRNA sequences and were enriched within a few days in both conditions. Other typical oil degrading bacteria such as Alcanivorax (n-alkane degrader) and Cycloclasticus (polycyclic aromatic hydrocarbons degrader) were rapidly enriched only in NSC conditions. Both the strong correlation between Oleispira SSU gene copies and oil concentration, and the specificity of the Oleispira assay suggest that this organism is a robust bioindicator for seawater contaminated by petroleum in cold water environments. Further optimization for automation of the Oleispira assay for in situ analysis with a genosensing device is underway. The assay for Colwellia quantification requires more specificity to fewer Colwellia OTUs and a well-established dose-response relationship before those taxa are used for oil tracking purposes. Unlabelled Image • Selection of oil-degrading bacterial OTUs as a proxy for rapid detection of oil in cold seawater • Colwellia OTUs dominant and diverse in all treatments, including control, and not oil-dose dependent • Oleispira response specific and oil-dose dependent • Performance of Oleispira assay appropriate for integration in autonomous real-time genosensing [ABSTRACT FROM AUTHOR]