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Cold-water coral (CWC) reefs are numerous and widespread along the Norwegian continental shelf where oil and gas industry operate. Uncertainties exist regarding their impacts from operational discharges to drilling. Effect thresholds obtained from near-realistic exposure of suspended particle concentrations for use in coral risk modeling are particularly needed. Here, nubbins of Desmophyllum pertusum (Lophelia pertusa) were exposed shortly (5 days, 4h repeated pulses) to suspended particles (bentonite BE; barite BA, and drill cuttings DC) in the range of ~ 4 to ~ 60 mg.l-1 (actual concentration). Physiological responses (respiration rate, growth rate, mucus-related particulate organic carbon OC and particulate organic nitrogen ON) and polyp mortality were then measured 2 and 6 weeks post-exposure to assess long-term effects. Respiration and growth rates were not significantly different in any of the treatments tested compared to control. OC production was not affected in any treatment, but a significant increase of OC:ON in mucus produced by BE-exposed (23 and 48 mg.l-1) corals was revealed 2 weeks after exposure. Polyp mortality increased significantly at the two highest DC doses (19 and 49 mg.l-1) 2 and 6 weeks post-exposure but no significant difference was observed in any of the other treatments compared to the control. These findings are adding new knowledge on coral resilience to short realistic exposure of suspended drill particles and indicate overall a risk for long-term effects at a threshold of ~20 mg.l-1. [ABSTRACT FROM AUTHOR]

Chronic oil pollution related to gas and oil drilling activities is increasing in the sea due to the rising offshore petroleum industry activity. Among marine organisms, zooplankton play a crucial role in the marine ecosystem and therefore understanding the effects of crude oil chronic exposure on zooplankton is needed to determine the impact of oil in marine environments. The present study reports on the effect of crude oil on adult northern krill, Meganyctiphanes norvegica , collected during three seasons. Their sensitivity to oil was examined with oil concentration of 0.01 versus 0.1 mg oil L − 1 and photo-modified oil in flowing seawater maintained in the dark for 2 weeks at in situ temperature. Oil (polycyclic aromatic hydrocarbons, PAHs) entered the krill (on average, 350 and 4400 μg·kg − 1 wet weight in low and medium oil treatments respectively) and a larger fraction of the krill exhibited digestive gland pathologies (enhanced apoptosis and pathology of digestive tubules) in oil treatments (27–80%) compared to a significantly lower fraction (7–13%) in treatments that received no oil. However, 2-week oil exposure at these concentrations did not significantly decrease survivorship or impair basic functioning such as feeding and respiration rates. Similarly, there were only limited changes in the transcription of 7 selected genes from head tissue. Additionally, although there was significant seasonal variation in krill total lipid content and fatty acid composition, there was no treatment effect on both these parameters, which suggests limited oxidative stress under experimental conditions. Furthermore, there was no significant treatment effect on two direct measures of oxidative stress (MDA: malondialdehyde and AOPP: advanced oxidation protein products) in any of the seasons. Nevertheless, histology clearly revealed enhanced digestive gland pathologies in krill even at low concentrations. Although krill with such pathologies continue to survive, their accumulation of PAHs may be transferred up the food chain, impacting their predators and the wider ecosystem. [ABSTRACT FROM AUTHOR]

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]

Climate models predict that the average temperature in the North Sea could increase 3-5 °C and surface-waters pH could decrease 0.3-0.5 pH units by the end of this century. Consequently, we investigated the combined effect of decreased pH (control pH 8.1; decreased pH 7.6) and temperature (control 6.7 °C; elevated 9.5 °C) on the hatching timing and success, and the zoeal development, survival, feeding, respiration and growth (up to stage IV zoea) of the northern shrimp, Pandalus borealis. At elevated temperature, embryos hatched 3 days earlier, but experienced 2-4 % reduced survival. Larvae developed 9 days faster until stage IV zoea under elevated temperature and exhibited an increase in metabolic rates (ca 20 %) and an increase in feeding rates (ca 15-20 %). Decreased pH increased the development time, but only at the low temperature. We conclude that warming will likely exert a greater effect on shrimp larval development than ocean acidification manifesting itself as accelerated developmental rates with greater maintenance costs and decreased recruitment in terms of number and size. [ABSTRACT FROM AUTHOR]

• Alpha Max at 1000X dilution of prescribed treatment is lethal to Pandalus borealis. • Only minor effects at the same dilution of the anti-parasitic drug Salmosan. • Combined exposure to Alpha Max and Salmosan caused similar effects as Alpha Max alone. • Delayed effects on larval survival and development after 2 h Alpha Max exposure. • No consequence of an added post-exposure stressor, starvation, on pesticide effects. Anti-parasitic drugs used in the aquaculture industry are discharged to the sea after treatment of salmon. In this study, the effects of azamethiphos (AZA) in the Salmosan® formulation and deltamethrin (DEL) in the Alpha Max® formulation, have been assessed in Northern shrimp larvae (Pandalus borealis) when administered both separately and in combination. The exposure concentrations were 100 ng/L for AZA and 2 ng/L for DEL, each representing a 1000-fold dilution of the prescribed concentrations for salmon. These two chemicals were combined at these concentrations to give a third treatment (AZA + DEL). When larvae were exposed for two hours on the first, second and third days post hatch (dph), significantly increased mortality and reduced swimming activity were observed for larvae from the DEL and combined AZA + DEL treatments 4 dph, though not in larvae from the AZA treatment. A single pulse exposure, delivered on the first day post hatch, caused similar effects on mortality and swimming activity 4 dph as the three-pulse exposure. Mortality was driven by the presence of DEL in both experiments, with no amplification or reduction of effects observed when DEL and AZA were combined. Larvae were observed for 13 days following the single pulse exposure, with food limitation introduced as an additional stressor on day 4. In the DEL and AZA + DEL treatments mortality continued to increase regardless of food level, with no larvae completing development to stage II. The overriding toxicity of DEL masked any potential effects the reduced food ration may have exerted. Swimming activity was lower for AZA treated larvae than Control larvae 13 dph, when both groups were fed daily, though no other significant changes to mortality, development to stage II, feeding rate or gene expression were observed. Food limited Control and AZA larvae had lower swimming activity and feeding rate than daily fed Control larvae, with expression of pyruvate kinase and myosin genes also downregulated. However, there was no negative effect on survival or successful development to stage II in these treatments. In addition, mesencephalic astrocyte-derived neurotropic factor was downregulated in food limited Control larvae when compared with the daily fed Controls. Results from this study together with reported estimates of dispersion plume concentrations of discharged pesticides indicate that toxic concentrations of deltamethrin could reach shrimp larvae several kilometers from a treated salmon farm. [ABSTRACT FROM AUTHOR]

Ocean warming (OW) and acidification (OA) are key features of global change and are predicted to have negative consequences for marine species and ecosystems. At a smaller scale increasing oil and gas activities at northern high latitudes could lead to greater risk of petroleum pollution, potentially exacerbating the effects of such global stressors. However, knowledge of combined effects is limited. This study employed a scenario-based, collapsed design to investigate the impact of one local acute stressor (North Sea crude oil) and two chronic global drivers (pH for OA and temperature for OW), alone or in combination on aspects of the biology of larval stages of two key invertebrates: the northern shrimp (Pandalus borealis) and the green sea urchin (Strongylocentrotus droebachiensis). Both local and global drivers had negative effects on survival, development and growth of the larval stages. These effects were species- and stage-dependent. No statistical interactions were observed between local and global drivers and the combined effects of the two drivers were approximately equal to the sum of their separate effects. This study highlights the importance of adjusting regulation associated with oil spill prevention to maximize the resilience of marine organisms to predicted future global conditions. [ABSTRACT FROM AUTHOR]

Ocean acidification (OA) is widely recognized as an increasing threat to marine ecosystems. Many marine invertebrates have dual-phase life cycles in which planktonic larvae connect and sustain otherwise disconnected benthic adult populations. Many planktonic larvae are particularly sensitive to environmental stresses including OA. Here, we compared the developmental dynamics, survivorship, and swimming behaviours of plutei of two ecologically important echinoderm species that naturally experience variability in ambient pH: the purple urchin Strongylocentrotus purpuratus and the infaunal brittlestar Amphiura filiformis. Sensitivity to decreased pH differed between these two species and between maternal lineages. Larvae of both species experienced increased mortality and reduced growth rate under low pH conditions. However, larval brittlestars appeared more sensitive and experienced over 80% mortality after 7-d exposure to pH 7.7. Larval urchins from one maternal lineage underwent highly synchronized budding (release of blastula-like particles) at low pH. Observed budding temporarily increased numerical density and reduced individual size, leading to differences in growth and mortality rates between the two half-sibling groups and another population. Swimming speeds of larval brittlestars were reduced in decreased pH. In contrast, acidification had either no effect or positive effect on swimming speeds of larval urchins. The observed differences between species may be a reflection of pre-exposure in their natural habitats: larval brittlestars experience a relatively stable in situ pH environment, whereas larval urchins are occasionally exposed to low pH in upwelling regions. Urchins may therefore exhibit short-term compensatory responses such as budding and increased swimming speed. Natural selection could act upon the significant variations we observed between maternal lineages, resulting in more resilient populations confronting chronic exposure to OA. [ABSTRACT FROM AUTHOR]

Ocean acidification (OA), the reduction of ocean pH due to hydration of atmospheric CO, is known to affect growth and survival of marine invertebrate larvae. Survival and transport of vulnerable planktonic larval stages play important roles in determining population dynamics and community structures in coastal ecosystems. Here, we show that larvae of the purple urchin, Strongylocentrotus purpuratus, underwent high-frequency budding (release of blastula-like particles) when exposed to elevated pCO level (>700 μatm). Budding was observed in >50 % of the population and was synchronized over short periods of time (~24 h), suggesting this phenomenon may be previously overlooked. Although budding can be a mechanism through which larval echinoids asexually reproduce, here, the released buds did not develop into viable clones. OA-induced budding and the associated reduction in larval size suggest new hypotheses regarding physiological and ecological tradeoffs between short-term benefits (e.g. metabolic savings and predation escape) and long-term costs (e.g. tissue loss and delayed development) in the face of climate change. [ABSTRACT FROM AUTHOR]

Increasing use of fish feed containing the chitin synthesis inhibiting anti-parasitic drug diflubenzuron (DFB) in salmon aquaculture has raised concerns over its impact on coastal ecosystems. Larvae of Northern shrimp ( Pandalus borealis ) were exposed to DFB medicated feed under Control conditions (7.0 °C, pH 8.0) and under Ocean Acidification and Warming conditions (OAW, 9.5 °C and pH 7.6). Two weeks’ exposure to DFB medicated feed caused significantly increased mortality. The effect of OAW and DFB on mortality of shrimp larvae was additive; 10% mortality in Control, 35% in OAW, 66% in DFB and 92% in OAW + DFB. In OAW + DFB feeding and swimming activity were reduced for stage II larvae and none of the surviving larvae developed to stage IV. Two genes involved in feeding ( GAPDH and PRLP ) and one gene involved in moulting ( DD9B ) were significantly downregulated in larvae exposed to OAW + DFB relative to the Control. Due to a shorter intermoult period under OAW conditions, the OAW + DFB larvae were exposed throughout two instead of one critical pre-moult period. This may explain the more serious sub-lethal effects for OAW + DFB than DFB larvae. A single day exposure at 4 days after hatching did not affect DFB larvae, but high mortality was observed for OAW + DFB larvae, possibly because they were exposed closer to moulting. High mortality of shrimp larvae exposed to DFB medicated feed, indicates that the use of DFB in salmon aquaculture is a threat to crustacean zooplankton. [ABSTRACT FROM AUTHOR]

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]