Here we demonstrate a distributed fibre optic sensor for the detection of liquid hydrocarbons. Two commercially available low-density ethylene-octene polyolefin elastomers with different properties ...are used to coat fibre optic cables, where the swelling of the coating upon absorption of hydrocarbons imparts strain on the fibre. By frequency domain analysis of the backscatter, the location of oil on the fibre is determined with high precision. The elastomer with the highest flexural modulus, hardness and tensile strength (Engage 8150) imposes more than three times more strain on the fibre compared to the softer elastomer (Engage 8180), despite the Engage 8180 expanding more than three times more in volume compared to the Engage 8150. A response occurs within a few seconds following oil interaction, and a maximum response of 700 microstrain (<inline-formula> <tex-math notation="LaTeX">\mu \varepsilon </tex-math></inline-formula>) is achieved with a response time of 1.5 minutes (t63) when a dry fibre is exposed to oil, whereas a maximum response of <inline-formula> <tex-math notation="LaTeX">400~\mu \varepsilon </tex-math></inline-formula> is achieved when the fibre is exposed to oil when submerged in water. The results demonstrate that optical fibres coated in this way are able to detect and locate small quantities of oil with high degree of spatial resolution. The technique could be scaled to fibre covering long distances, and makes the sensor interesting for pipeline leak detection both on -and offshore, as well as for oil production monitoring purposes downhole.
Near-shore areas face multiple stressors, effects of climate change, coastal construction and contamination. Although capping the seabed in these areas with mineral masses can reduce the impact of ...legacy contaminants in sediment, it can also result in the loss of flora and sessile fauna, both of which are vital components of near-shore ecosystems. Eelgrass (Zostera marina) is essential to marine near-shore areas as it supports biodiversity and mitigates the effects of climate change. Therefore, it would be beneficial to modify the top layer of caps to facilitate the reestablishment of these ecosystems when capping near-shore areas. This study describes results from an in situ, six-month field experiment conducted to compare increase in leaf length over the growing season and survival of eelgrass transplanted in two commercially available substrates (Natural sand and Crushed stone) and indigenous sediment (i.e., indigenous control sediment) in a capping project in Horten Inner harbour, Norway. Similar leaf length increase was found in Natural sand and Indigenous control sediment, both significantly higher compared to Crushed stone substrate. Survival was highest in our case in the Indigenous control sediment (120 %), with no significant difference between Crushed stone (20 %) and Natural sand substrates (25 %). These findings emphasize the importance of selecting appropriate substrate for successful seagrass restoration.
•Commercial substrates and indigenous sediment tested for seagrass reestablishment.•Lack of fine grains resulted in low survival of eelgrass in commercial substrate.•Eelgrass growth was low in substrate with chipped grains.•Growth and survival were best in indigenous substrate.
•Zooplankton may contribute to oil fate through ingestion of oil droplets.•Feces were collected from Calanus finmarchicus after exposure to oil dispersions.•Oil-containing feces had high ...concentrations of oil-degrading activity.•Total bacterial communities were similar between clean and oil-containing feces.•Zooplankton feces can contribute to high oil-degrading activity during oil spills.
Zooplankton are suggested to be biotic contributors to the transport and weathering of oil in marine environments due to their ingestion of oil. In the present experiment, feeding activity and microbial communities in feces from Calanus finmarchicus feeding in oil dispersions were characterized. Feeding activity was significantly reduced in oil dispersions. The microbial communities in clean and oil-containing copepod feces were dominated by Rhodobacteraceae family bacteria (Lesingera, Phaeobacter, Rugeria, and Sulfitobacter), which were suggested to be indigenous to copepod feces. The results also indicated that these bacteria were metabolizing oil compounds, as a significant increase in the concentrations of viable oil degrading microorganisms was observed in oil-containing feces. This study shows that bacteria in feces from copepods feeding in dilute oil dispersions have capacity for degradation of oil. Zooplankton may therefore contribute to weathering of oil by excreting feces with microbial communities already adapted to degradation of oil.
To determine biotransformation of components in crude oil dispersions in the presence of feces from marine copepods, dispersed oil was incubated alone, with the addition of clean or oil-containing ...feces. We hypothesized that the feces would contribute with nutrients to bacteria, and higher concentrations of oil-degrading bacteria, respectively. Presence of clean feces resulted in higher degradation of aromatic oil compounds, but lower degradation of n-alkanes. Presence of oil-containing feces resulted in higher degradation of n-alkanes. The effect of clean feces on aromatic compounds are suggested to be due to higher concentrations of nutrients in the seawater where aromatic degradation takes place, while the lower degradation of n-alkanes are suggested to be due to a preference by bacteria for feces over these compounds. Large aggregates were observed in oil dispersions with clean feces, which may cause sedimentation of un-weathered lipophilic oil compounds towards the seafloor if formed during oil spills.
•Degradation of oil spills may be enhanced by the addition of inorganic nutrients.•Copepod feces are high in nutrient and contain bacteria that can degrade oil.•Oil dispersions were incubated with clean and oil-containing copepod feces.•Biodegradation was high for dissolved oil compounds in the presence of clean feces.•The indigenous feces bacteria were suggested to be capable of degradation of oil.
Oil droplets may form and disperse in the water column after an accidental spill of crude oil or petroleum products at sea. Micro-sized oil droplets may be available for filter feeding organisms, ...such as the copepod Calanus finmarchicus, which has been shown to filter oil droplets. In the present paper, a modeling approach was used to estimate potential ingestion amounts by copepod filtration of oil droplets. The new model was implemented in the OSCAR (Oil Spill Contingency and Response) software suite, and tested for a series of oil spill scenarios and key parameters. Among these, the size of the filtered droplets was found to be the most important factor influencing the model results. Given the assumptions and simplifications of the model, filtration of dispersed crude oil by C. finmarchicus was predicted to affect the fate of 1−40% of the total released oil mass, depending on the release scenario and parameter values used, with the lower end of that range being more probable in an actual spill situation.
•We model copepod filtration of oil droplets following an oil spill.•Filtration was estimated to affect 1–40 % of the total mass of spilled oil.•Size range of filterable oil droplets was the most important model parameter.
Produced water is a complex mixture discharged to sea in high volumes containing compounds at low concentrations. Compounds in mixtures can modify each other's expected toxic effect predicted from ...single exposure, and to obtain information about potential interactions is important. Carbazole is present in produced water and is suggested to contribute to produced waters potential of modifying cytochrome P450 (CYP) activity. Information on toxic effect of carbazole in relation to produced water is limited. Carbazole is included in this project to study its potential for modifying CYP 1A activity singly and in mixtures. The aromatic and phenolic fractions of produced water are significant contributors to toxicity and concentration of organic compounds in produced water. As representative compounds of these fractions, benzo(a)pyrene (BaP) and 2,5-dimethylphenol (DMP) are included in this master project. Biotransformation of harmful compounds is often initiated by CYPs catalysing oxidation reactions. Modified CYP 1A protein or activity is an indication of interaction between a compound and the biological system. Biotransformation catalysed by CYP 1A can produce reactive oxygen species (ROS) and reactive metabolites. Increased contaminant load can deplete reduced glutathione (GSH) through increase in conjugation reactions. In addition to being an important conjugate, GSH is also an important antioxidant. With potential both to increase extent of DNA damage by increasing levels of ROS and producing reactive metabolites, and interfere with glutathione dependent defence protecting against oxidative stress, compounds interacting with CYP 1A and conjugation enzymes are suggested to contribute to DNA damage. The aims of this master project were to determine carbazoles potential for modifying CYP 1A activity measured as ethoxyresorufin-O-deethylase (EROD) activity, to evaluate interaction in ternary mixtures with carbazole and two compounds representing fractions contributing to toxicity of produced water, and also to study correlation between biotransformation activity and genotoxicity by measuring DNA double strand breaks (DSB). The aims were achieved by studying single compounds and ternary mixture in vitro in the continuous cell line PLHC-1. Concentrations of the three compounds in the ternary mixtures were varied using a statistical design. Results were analysed using partial least squares projection to latent structures (PLS). Concentrations of the compounds included in the design were determined from cytotoxicity results, EROD concentration effect curves for single compounds and concentrations measured in the marine environment. It was hypothesized that compounds will modify EROD activity in PLHC-1 differently when present in ternary mixtures compared to single exposure. It was further suggested that ternary mixtures inducing high EROD activity also will enhance formation of DNA DSB in PLHC-1 cells. Carbazole was suggested to modify EROD activity induced by the other compounds. Exposure of PLHC-1 to BaP singly significant induced EROD activity. Carbazole induced EROD activity slightly, and significant for the highest concentration in one replicate. An overall non-significant decrease in EROD activity was seen in PLHC-1 exposed to DMP. Exposure of PLHC-1 to ternary mixtures resulted in significant and positive PLS regression coefficient for both BaP and carbazole. The crossed term carbazole×DMP decreased EROD activity significantly. Squared terms for all three compounds were significant, equal and negative.The results indicate that potential of carbazole at inducting CYP 1A is different alone compared to when it is present in mixture. Carbazole is suggested to contribute to EROD inducing potency in the ternary mixtures. Effect of carbazole on EROD activity is indicated to be dependent on co-exposed compounds. How EROD activity is modulated when exposed to DMP is suggested to be dependent on exposure conditions. The significant substantial square terms indicate that all three compounds interact with catalytic EROD activity at higher concentrations. Catalytic EROD activity is presumed to be a good indication of potential interaction between compounds and biological systems. Determining extent of DNA damage by electrophoretic separation of DNA did not give consistent result. Electrophoretic separation of DNA from PLHC-1 is assumed to be more pertinent for determining genotoxicity of certain metals in PLHC-1. Statistical design and projection techniques are considered valuable tools when assessing toxicity of mixtures.
Provider: - Institution: - Data provided by Europeana Collections- Produced water is a complex mixture discharged to sea in high volumes containing compounds at low concentrations. Compounds in ...mixtures can modify each others expected toxic effect predicted from single exposure, and to obtain information about potential interactions is important. Carbazole is present in produced water and is suggested to contribute to produced waters potential of modifying cytochrome P450 (CYP) activity. Information on toxic effect of carbazole in relation to produced water is limited. Carbazole is included in this project to study its potential for modifying CYP 1A activity singly and in mixtures. The aromatic and phenolic fractions of produced water are significant contributors to toxicity and concentration of organic compounds in produced water. As representative compounds of these fractions, benzo(a)pyrene (BaP) and 2,5-dimethylphenol (DMP) are included in this master project. Biotransformation of harmful compounds is often initiated by CYPs catalysing oxidation reactions. Modified CYP 1A protein or activity is an indication of interaction between a compound and the biological system. Biotransformation catalysed by CYP 1A can produce reactive oxygen species (ROS) and reactive metabolites. Increased contaminant load can deplete reduced glutathione (GSH) through increase in conjugation reactions. In addition to being an important conjugate, GSH is also an important antioxidant. With potential both to increase extent of DNA damage by increasing levels of ROS and producing reactive metabolites, and interfere with glutathione dependent defence protecting against oxidative stress, compounds interacting with CYP 1A and conjugation enzymes are suggested to contribute to DNA damage. The aims of this master project were to determine carbazoles potential for modifying CYP 1A activity measured as ethoxyresorufin-O-deethylase (EROD) activity, to evaluate interaction in ternary mixtures with carbazole and two compounds representing fractions contributing to toxicity of produced water, and also to study correlation between biotransformation activity and genotoxicity by measuring DNA double strand breaks (DSB). The aims were achieved by studying single compounds and ternary mixture in vitro in the continuous cell line PLHC-1. Concentrations of the three compounds in the ternary mixtures were varied using a statistical design. Results were analysed using partial least squares projection to latent structures (PLS). Concentrations of the compounds included in the design were determined from cytotoxicity results, EROD concentration effect curves for single compounds and concentrations measured in the marine environment. It was hypothesized that compounds will modify EROD activity in PLHC-1 differently when present in ternary mixtures compared to single exposure. It was further suggested that ternary mixtures inducing high EROD activity also will enhance formation of DNA DSB in PLHC-1 cells. Carbazole was suggested to modify EROD activity induced by the other compounds. Exposure of PLHC-1 to BaP singly significant induced EROD activity. Carbazole induced EROD activity slightly, and significant for the highest concentration in one replicate. An overall non-significant decrease in EROD activity was seen in PLHC-1 exposed to DMP. Exposure of PLHC-1 to ternary mixtures resulted in significant and positive PLS regression coefficient for both BaP and carbazole. The crossed term carbazole×DMP decreased EROD activity significantly. Squared terms for all three compounds were significant, equal and negative.The results indicate that potential of carbazole at inducting CYP 1A is different alone compared to when it is present in mixture. Carbazole is suggested to contribute to EROD inducing potency in the ternary mixtures. Effect of carbazole on EROD activity is indicated to be dependent on co-exposed compounds. How EROD activity is modulated when exposed to DMP is suggested to be dependent on exposure conditions. The significant substantial square terms indicate that all three compounds interact with catalytic EROD activity at higher concentrations. Catalytic EROD activity is presumed to be a good indication of potential interaction between compounds and biological systems. Determining extent of DNA damage by electrophoretic separation of DNA did not give consistent result. Electrophoretic separation of DNA from PLHC-1 is assumed to be more pertinent for determining genotoxicity of certain metals in PLHC-1. Statistical design and projection techniques are considered valuable tools when assessing toxicity of mixtures.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
