Water Column Monitoring 2009

The report presents results from the Water Column Monitoring 2009, performed in collaboration between NIVA and IRIS, with sub-contractors. The objective of the survey was to assess the extent to which produced water discharges from Ekofisk affect organisms living in the water column. The study was designed to monitor bio-accumulation and biomarker responses in organisms held in cages in the vicinity of the water discharge point(s). The study design was identical to that carried out at Ekofisk in 2006 and 2008 with only minor modifications where necessary. The implementation of a produced water treatment system (C-Tour), operational in 2008, aimed to reduce the output of potentially toxic chemicals into the surrounding water column. The monitoring surveys performed pre and post implementation of C-Tour, were designed to assess whether changes in animal health status between the different years have occurred. The results of the 2009 survey have shown that caged organisms were exposed to low levels of produced water components with highest tissue concentrations in mussels Mytilus edulis, located closest to the produced water discharge. Mussels located approximately 1-2 km away showed only background concentrations of the organic compounds measured. Concentrations of polycyclic aromatic hydrocarbon (PAH) and alkyl phenol (AP)-metabolites in bile of caged cod Gadus morhua, were slightly elevated suggesting exposure at the Ekofisk stations. There was a signal of exposure with proximity to the discharge for some of the biomarkers measured including CYP1A in fish and micronuclei in mussels. However, all other fish and mussel biomarkers showed no significant exposure effects. The bioaccumulation data and biomarker responses indicated a lower exposure to the produced water effluent than seen previously in 2008 and 2006. The volume of produced water discharged to the investigated area increased in 2009 from 2008 and 2006. However, the amount of oil discharged with the produced water was less, resulting in an overall reduction of oil to the local area. This reduction in oil discharge was reflected in the bioaccumulation and biomarker data, resulting in a general improvement in the health of caged mussels and fish in 2009 compared to 2008 and 2006. Overall, based on the bioaccumulation and biomarker data in 2009, the current environmental risk of the PW on animals living in the water column in proximity to the platforms is low.ConocoPhillips on behalf of the OLF WCM coordination grou

Seawater carbonate chemistry and biological processes of Mytilus edulis during experiments, 2011

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

Seawater carbonate chemistry and biological processes of Pandalus borealis during experiments, 2011

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

Seawater carbonate chemistry and mortality, morphology, feeding rate, metabolic rate and activity of two keystone marine invertebrates

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