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Honsvall B.K.,Buskerud and Vestfold University College | Honsvall B.K.,Trilobite Microsystems AS | Altin D.,BioTrix | Robertson L.J.,Norwegian University of Life Sciences
Bioresource Technology | Year: 2016

A new microfluidic chip based on a trilobite structure, designed for continuously concentrating particles in moving fluids, was investigated as a pre-concentration method for microalgal harvesting. The chip has a 5-μm gap limit and was tested for concentrating the microalgae Rhodomonas baltica, Chaetoceros sp. and Thalassiosira weissflogii. The chip was able to concentrate rigid cells and to sort them according to size. However, optimization with respect to cell properties, such as size and flexibility, needs further work. Although no clogging of the chip was seen for R. baltica and Chaetoceros sp., production of exopolymers by T. weissflogii made harvesting challenging for this species. The Trilobite™ microfluidic chip appears to be a promising tool for pre-concentrating microalgae that are difficult to harvest due to their repelling properties or small size. © 2015 Elsevier Ltd.

Olsen A.J.,Norwegian University of Science and Technology | Nordtug T.,Sintef | Altin D.,BioTrix | Lervik M.,Norwegian University of Science and Technology | Hansen B.H.,Sintef
Environmental Toxicology and Chemistry | Year: 2013

Following a 120-h exposure period to 3 concentrations of oil dispersions (0.022mgL-1, 1.8mgL-1, and 16.5mgL-1, plus controls) generated from a North Sea crude oil and a subsequent 21-d recovery, mortality, and several reproduction endpoints (egg production rates, egg hatching success, and fraction of females participating in reproduction) in Calanus finmarchicus were studied. Concentration-dependent mortality was found during exposure, averaging to 6%, 3%, 15%, and 42% for the controls and 3 exposure levels, respectively. At the start of the recovery period, mean egg production rates of surviving females from the highest concentrations were very low, but reproduction subsequently improved. In a 4-d single female reproduction test starting 13 d postexposure, no significant differences in egg production rates or hatching success were found between reproducing control and exposed copepods. However, a significantly lower portion of the surviving females from the highest exposure participated in egg production. The results indicate that although short-term exposure to oil-polluted water after an oil spill can induce severe mortality and temporarily suspend reproduction, copepods may recover and produce viable offspring soon after exposure. The results might imply that for C. finmarchicus populations, the impact from short-term exposure to an oil spill might be predicted from acute mortality and that delayed effects make only a limited contribution to population decrease. © 2013 The Authors.

Hansen B.H.,Sintef | Altin D.,BioTrix | Olsen A.J.,Norwegian University of Science and Technology | Nordtug T.,Sintef
Ecotoxicology and Environmental Safety | Year: 2012

Following oil spills in the marine environment, natural dispersion (by breaking waves) will form micron-sized oil droplets that disperse into the pelagic environment. Enhancing the dispersion process chemically will increase the oil concentration temporarily and result in higher bioavailability for pelagic organisms exposed to oil-dispersant plume. The toxicity of dispersed oil to pelagic organisms is a critical component in evaluating the net environmental consequences of dispersant use or non-use in open waters. To assess the potential for environmental effects, numerical models are being used, and for these to reliably predict the toxicity of chemically dispersed oil, it is essential to know if the dispersant affects the specific toxicity of the oil itself. In order to test the potential changes in specific toxicity of the oil due to the presence of chemical dispersant, copepods (Calanus finmarchicus) were subjected to a continuous exposure of chemically (4 percent Dasic w/w dispersant) and naturally dispersed oil (same droplet size range and composition) for four days. On average the addition of dispersant decreased 96h LC50-values by a factor of 1.6, while for LC10 and LC90 these factors were 2.9 and 0.9, respectively. This indicates that after 96h of exposure the dispersant slightly increased the specific toxicity of the oil at median and low effect levels, but reduced the toxicity at high effect levels. Decreased filtrations for the exposed groups were confirmed using particle counting and fluorescence microscopy. However, no differences in these endpoints were found between chemically and naturally dispersed oil. The ultimate goal was to evaluate if models used for risk and damage assessment can use similar specific toxicity for both chemically and naturally dispersed oil. The slight differences in toxicity between chemically and naturally dispersed oil suggest that risk assessment should be based on the whole concentration response curve to ensure survival of C. finmarchicus. © 2012 Elsevier Inc.

Nordtug T.,Sintef | Olsen A.J.,Norwegian University of Science and Technology | Altin D.,BioTrix | Overrein I.,Sintef | And 3 more authors.
Science of the Total Environment | Year: 2011

Oil exploration and production in the Atlantic moves northwards towards spawning and nursery areas of fish species that sustain some of the world's largest fisheries. Models are therefore needed that can simulate the effects of accidental oil spills on early life stages of these fish. In this study, we combined an individual based model and a microcosm approach to infer effects of the water soluble fraction (WSF) and of an oil dispersion (WSF and droplets) on two key endpoints of North East Arctic cod (Gadus morhua) larvae: food assimilation rate and survival probability. Both exposure types (WSF and dispersion) decreased assimilation rate (control: 0.4d -1) and survival probability (control: 0.96) in a concentration-dependent fashion, with EC 50s of about 2 (feeding) and 40μg/L ∑PAH in the WSF (survival probability). No consistent differences were found between the ECs from the two exposure types indicating no additional oil droplet effects in the oil dispersion. During post exposure, effects on the two endpoints disappeared, which was confirmed by an image analyses we performed of gut content fluorescence. Our results also show that the larvae model fitted the experimental data from the two exposure types equally well, indicating that the presence of oil droplets did not affect model performance. More complex models that explicitly consider possible mechanisms of oil droplet toxicity - in addition to the toxicity of the WSF - on the two examined endpoints during a 17day time frame do therefore not have a higher accuracy than simpler models that neglect oil droplet toxicity. © 2011 Elsevier B.V.

Nordtug T.,Sintef | Olsen A.J.,Norwegian University of Science and Technology | Salaberria I.,Norwegian University of Science and Technology | Overjordet I.B.,Sintef | And 3 more authors.
Environmental Toxicology and Chemistry | Year: 2015

The rates of ingestion of oil microdroplets and oil fouling were investigated in the zooplankton filter-feeder Calanus finmarchicus (Gunnerus, 1770) at 3 concentrations of oil dispersions ranging from 0.25 mg/L to 5.6 mg/L. To compare responses to mechanically and chemically dispersed oil, the copepods were exposed to comparable dispersions of micron-sized oil droplets made with and without the use of a chemical dispersant (similar oil droplet size range and oil concentrations) together with a constant supply of microalgae for a period of 4 d. The filtration rates as well as accumulation of oil droplets decreased with increasing exposure concentration. Thus the estimated total amount of oil associated with the copepod biomass for the 2 lowest exposures in the range 11 mL/kg to 17 mL/kg was significantly higher than the approximately 6 mL/kg found in the highest exposure. For the 2 lowest concentrations the filtration rates were significantly higher in the presence of chemical dispersant. Furthermore, a significant increase in the amount of accumulated oil in the presence of dispersant was observed in the low exposure group. © 2015 SETAC.

Bergvik M.,Norwegian University of Science and Technology | Leiknes O.,Norwegian University of Science and Technology | Altin D.,Biotrix | Dahl K.R.,Norwegian University of Science and Technology | Olsen Y.,Norwegian University of Science and Technology
Lipids | Year: 2012

Calanus finmarchicus is the dominant zooplankton species in the North Atlantic. This zooplankton is also of interest for commercial harvesting due to its high abundance and biochemical contents. In the present study, copepodite stage V of C. finmarchicus was sampled at different depths from January to June in 2009, 2010 and 2011 in the Trondheimsfjord (63°29′N 10°18′E). The fatty acid composition was analyzed in individual copepods and in the seston. It was found that the fatty acid profile of copepods was related to the fatty acid profile of potential food sources. This study indicates that the onset of vertical migration of stage V, which was observed in May, has a strong link to the production of phytoplankton and lipid accumulation in C. finmarchicus. The content of 14:0 and 16:0 fatty acids in the specimens did not increase from February to May in surface waters. This suggests that these fatty acids in the diet were used as precursors for the biosynthesis of 20:1n-9 and 22:1n-11 fatty acids and fatty alcohols. A potential harvesting season of C. finmarchicus could be when the species is abundant in surface waters; the content of n-3 fatty acids will vary throughout this season. The peak abundance of C. finmarchicus in the spring varied substantially between the years studied. © AOCS 2012.

Hansen B.H.,Sintef | Altin D.,BioTrix | Overjordet I.B.,Sintef | Jager T.,VU University Amsterdam | Nordtug T.,Sintef
Science of the Total Environment | Year: 2013

The use of marine diesels in Arctic areas is expected to increase due to increased shipping transport, oil and gas activities, and the ban of heavy bunker oils in many areas. This project aimed at gathering information regarding the sensitivity of an Arctic copepod to marine diesel. The approach undertaken was to study the effects on survival (LC50s) and gene expression of a known detoxification gene (glutathione S-transferase [GST]) in Calanus glacialis following exposure to water soluble fractions (WSFs) of marine diesel (at 2°C). We compared the observed LC-values of C. glacialis to the identical experimental data of the boreal Calanus finmarchicus (at 10°C), and to the predicted LC50-values using regression models. The C. glacialis appeared more tolerant to the acute effects of marine diesel WSF compared to the "average pelagic crustacean" as predicted by regression models, and compared to C. finmarchicus. Although these results may be explained by a slower equilibration of petrogenic chemicals from the WSF at lower temperatures, C. glacialis also displayed higher GST expression following exposure than C. finmarchicus. In addition, the lipid content of the test organisms appears to be an important factor for the determination of acute toxicity, as copepods with high lipid content survived longer than copepods with low lipid content. © 2013 Elsevier B.V.

Olsvik P.A.,National Institute of Nutrition And Seafood Research | Nordtug T.,Sintef | Altin D.,Biotrix | Lie K.K.,National Institute of Nutrition And Seafood Research | And 2 more authors.
Chemosphere | Year: 2010

Polycyclic aromatic hydrocarbons (PAHs) and other oil compounds are known to induce stress and impact health of marine organisms. Water-soluble fractions of oil contain components known to induce glutathione S-transferases (GSTs), one of the major classes of phase II detoxifying enzymes present in essentially all eukaryotic organisms. In this study, the transcriptional responses of six GSTs (GST pi, GST mu, GST omega, GST theta, GSY zeta and GST kappa) were examined in early larvae of Atlantic cod Gadus morhua exposed to five concentrations of dispersed oil (containing oil droplets and water-soluble fraction) and water-soluble fractions (WSF) of oil. When Atlantic cod larvae were exposed to WSF (containing 1.31 ± 0.31 μg ∑PAH/L for 4 days), expression of GSTM3 and GSTO1 was significantly increased, whereas no differences in GST expression were observed in larvae exposed to a corresponding 50% lower amount of dispersed oil (containing 0.36 ± 0.10 μg ∑PAH/L for 4 days). The study suggest that although the oil clearly had severe negative effects on the larvae (i.e. concentration-dependent lethality and growth reduction), only minor effects on GST transcription could be observed using RNA obtained from pooled whole-larvae homogenates. This result indicates that the expression of these important detoxification enzymes is only moderately inducible at such an early developmental stage either reflecting low tolerance of cod larvae to dispersed oil or alternatively that using whole-larvae homogenates may have masked tissue-specific mRNA induction. © 2010 Elsevier Ltd. All rights reserved.

Pedersen S.A.,Norwegian University of Science and Technology | Hansen B.H.,Sintef | Altin D.,BioTrix | Olsen A.J.,Norwegian University of Science and Technology
Biogeosciences | Year: 2013

The impact of medium-term exposure to CO2-acidified seawater on survival, growth and development was investigated in the North Atlantic copepod Calanus finmarchicus. Using a custom developed experimental system, fertilized eggs and subsequent development stages were exposed to normal seawater (390 ppm CO2) or one of three different levels of CO 2-induced acidification (3300, 7300, 9700 ppm CO2). Following the 28-day exposure period, survival was found to be unaffected by exposure to 3300 ppm CO2, but significantly reduced at 7300 and 9700 ppm CO2. Also, the proportion of copepodite stages IV to VI observed in the different treatments was significantly affected in a manner that may indicate a CO2-induced retardation of the rate of ontogenetic development.Morphometric analysis revealed a significant increase in size (prosome length) and lipid storage volume in stage IV copepodites exposed to 3300 ppm CO2 and reduced size in stage III copepodites exposed to 7300 ppm CO2. Together, the findings indicate that a pCO2 level ≤2000 ppm (the highest CO 2 level expected by the year 2300) will probably not directly affect survival in C. finmarchicus. Longer term experiments at more moderate CO2 levels are, however, necessary before the possibility that growth and development may be affected below 2000 ppm CO2 can be ruled out.©Author(s) 2013 CC Attribution 3.0 License.

Hansen B.H.,Sintef | Altin D.,BioTrix | Rorvik S.F.,Norwegian University of Science and Technology | Overjordet I.B.,Norwegian University of Science and Technology | And 2 more authors.
Science of the Total Environment | Year: 2011

Extrapolation of ecotoxicological data from temperate species for use in risk assessment in the polar environments may be difficult since polar organisms as a rule differ from temperate species in terms of life span length, developmental time, surface-to-volume ratios, metabolic rates, total energy usage and lipid content for energy storage. In the current work we performed a comparative study where two closely related and morphologically similar copepod species, Calanus finmarchicus (temperate-boreal) and Calanus glacialis (arctic), were exposed to water accommodated fractions (WAF) of oil in a series of parallel experiments. The two species, adapted to 10°C and 2°C, respectively, were compared on the basis of acute ecotoxicity (LC50) and the WAF-mediated induction of the gene encoding glutathione S-transferase (GST). In addition, an experiment was conducted in order to reveal relationships between lipid content and acute toxicity. LC50 values differed between the two species, and the Arctic copepod appeared less sensitive than the temperate-boreal species. The lipid contents of the two species, measured biometrically, were comparable, and the relationships between lipid content and response (reduced survival) to acute WAF exposure followed the same trend: Lipid-rich copepods survived longer than lipid-poor copepods at the same exposure concentration. In terms of GST expression, both species showed concentration-dependent and exposure time-dependent trends. However, as for the acute toxicity data, the Arctic copepod appeared to respond slower and with a lower intensity. From the study it can be concluded that temperature and lipid content are important factors for assessing differences between temperate and Arctic species, and that a delayed response in organisms adapted to low temperatures needs to be corrected for when extrapolating toxicity data from species with other temperature optimums for use in Arctic environments. © 2010 Elsevier B.V.

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