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Rising oil and gas activities in northern high latitudes have led to an increased risk of petroleum pollution in these ecosystems. Further, seasonal high UV radiation at high latitudes may elevate photo-enhanced toxicity of petroleum pollution to marine organisms. Zooplanktons are a key ecological component of northern ecosystems; therefore, it is important to assess their sensitivity to potential pollutants of oil and gas activity. As ontogenetic development may be particularly sensitive, the aim of this study was to examine the impact of chronic exposure to oil water dispersion (OWD) on development and feeding of early life stages of the Northern krill,Meganyctiphanes norvegica. In a range of experiments, embryonic, nonfeeding, and feeding larval stages were exposed to concentrations of between 0.01 and 0.1 mg/L of oil or photo-modified oil for 19 and 21 d. No significant effects on egg respiration, hatching success, development, length and larval survival were observed from these treatments. Similarly, evolution of fatty acid composition patterns during ontogenetic development was unaffected. The results indicates a high degree of resilience of these early developmental stages to such types and concentrations of pollutants. However, feeding and motility in later calyptopis-stage larvae were significantly impaired at exposure of 0.1 mg/L oil. Data indicate that feeding larval stage of krill was more sensitive to OWD than early nonfeeding life stages. This might be attributed to the narcotic effects of oil pollutants, their direct ingestion, or accumulated adverse effects over early development. [ABSTRACT FROM PUBLISHER]

Ocean acidification (OA) resulting from anthropogenic emissions of carbon dioxide (CO2) 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 CO2 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 CaCO3), 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. [ABSTRACT FROM AUTHOR]