Impact of flow field resolution on produced water transport in Lagrangian and Eulerian models.

During offshore petroleum production, large volumes of produced water are continuously discharged. The environmental impact from such discharges is typically assessed with numerical models, which simulate the transport and dilution of the produced water plume in order to predict environmental concentrations of its chemical constituents. In this study we investigate the effects of model resolution (800 m and 4 km) on produced water dispersion. We also compare two different types of models, a Lagrangian particle model, and an Eulerian grid-based ocean model to assess the Eulerian consistency of the Lagrangian model. We consider a point source off the coast of mid-Norway, during two different seasons (winter and spring). In general, the two models are in reasonable agreement. We find a substantial difference in tracer distribution and concentrations between the two resolutions, and to a lesser extent between seasons; in particular, the 800 m model shows lower concentrations along the coast.

Sea ice decline drives biogeographical shifts of key Calanus species in the central Arctic Ocean.

In recent decades, the central Arctic Ocean has been experiencing dramatic decline in sea ice coverage, thickness and extent, which is expected to have a tremendous impact on all levels of Arctic marine life. Here, we analyze the regional and temporal changes in pan-Arctic distribution and population structure of the key zooplankton species Calanus glacialis and C. hyperboreus in relation to recent changes in ice conditions, based on historical (1993-1998) and recent (2007-2016) zooplankton collections and satellite-based sea ice observations. We found strong correlations between Calanus abundance/population structure and a number of sea ice parameters. These relationships were particularly strong for C. glacialis, with higher numbers being observed at locations with a lower ice concentration, a shorter distance to the ice edge, and more days of open water. Interestingly, early stages of C. hyperboreus followed the same trends, suggesting that these two species substantially overlap in their core distribution area in the Arctic Ocean. Calanus glacialis and C. hyperboreus have been historically classified as shelf versus basin species, yet we conclude that both species can inhabit a wide range of bottom depths and their distribution in the Arctic Ocean is largely shaped by sea ice dynamics. Our data suggest that the core distribution patterns of these key zooplankton are shifting northwards with retreating sea ice and changing climate conditions.

Simulating crude oil exposure, uptake and effects in North Atlantic Calanus finmarchicus populations.

A simulation model framework (SYMBIOSES) that includes a 3-dimensional ocean physics and biology model and a model for transport and fate of oil was used to investigate the potential for bioaccumulation and lethal/sublethal effects of oil components in the copepod Calanus finmarchicus in the Lofoten-Vesterålen archipelago of Norway. The oil model is coupled with the biology model by way of a bioaccumulation model, from which mortality and reduction in reproduction are calculated via a total body burden (TBB). The simulation results indicate that copepod body burden levels are affected by the spill type (surface spill, subsea blowout) and the spill timing (spring, autumn). The effects of oil component bioaccumulation on the copepod population for all scenarios are small, though greatest in the subsea blowout scenarios. We attribute this to the limited spatial and temporal overlap between copepods and oil in the environment simulated by the model. The coupling of the processes of oil transport, bioaccumulation/excretion and the associated effects are discussed in the context of the model framework and with a view towards applications for Ecological Risk Assessment (ERA).

Toward adaptive robotic sampling of phytoplankton in the coastal ocean.

Currents, wind, bathymetry, and freshwater runoff are some of the factors that make coastal waters heterogeneous, patchy, and scientifically interesting-where it is challenging to resolve the spatiotemporal variation within the water column. We present methods and results from field experiments using an autonomous underwater vehicle (AUV) with embedded algorithms that focus sampling on features in three dimensions. This was achieved by combining Gaussian process (GP) modeling with onboard robotic autonomy, allowing volumetric measurements to be made at fine scales. Special focus was given to the patchiness of phytoplankton biomass, measured as chlorophyll a (Chla), an important factor for understanding biogeochemical processes, such as primary productivity, in the coastal ocean. During multiple field tests in Runde, Norway, the method was successfully used to identify, map, and track the subsurface chlorophyll a maxima (SCM). Results show that the algorithm was able to estimate the SCM volumetrically, enabling the AUV to track the maximum concentration depth within the volume. These data were subsequently verified and supplemented with remote sensing, time series from a buoy and ship-based measurements from a fast repetition rate fluorometer (FRRf), particle imaging systems, as well as discrete water samples, covering both the large and small scales of the microbial community shaped by coastal dynamics. By bringing together diverse methods from statistics, autonomous control, imaging, and oceanography, the work offers an interdisciplinary perspective in robotic observation of our changing oceans.

Net primary productivity estimates and environmental variables in the Arctic Ocean: An assessment of coupled physical-biogeochemical models.

The relative skill of 21 regional and global biogeochemical models was assessed in terms of how well the models reproduced observed net primary productivity (NPP) and environmental variables such as nitrate concentration (NO3), mixed layer depth (MLD), euphotic layer depth (Zeu), and sea ice concentration, by comparing results against a newly updated, quality-controlled in situ NPP database for the Arctic Ocean (1959-2011). The models broadly captured the spatial features of integrated NPP (iNPP) on a pan-Arctic scale. Most models underestimated iNPP by varying degrees in spite of overestimating surface NO3, MLD, and Zeu throughout the regions. Among the models, iNPP exhibited little difference over sea ice condition (ice-free versus ice-influenced) and bottom depth (shelf versus deep ocean). The models performed relatively well for the most recent decade and toward the end of Arctic summer. In the Barents and Greenland Seas, regional model skill of surface NO3 was best associated with how well MLD was reproduced. Regionally, iNPP was relatively well simulated in the Beaufort Sea and the central Arctic Basin, where in situ NPP is low and nutrients are mostly depleted. Models performed less well at simulating iNPP in the Greenland and Chukchi Seas, despite the higher model skill in MLD and sea ice concentration, respectively. iNPP model skill was constrained by different factors in different Arctic Ocean regions. Our study suggests that better parameterization of biological and ecological microbial rates (phytoplankton growth and zooplankton grazing) are needed for improved Arctic Ocean biogeochemical modeling.

The influence of long-term awareness of hyperlipidemia and of 3 years of dietary counseling on depression, anxiety, and quality of life.

OBJECTIVE: The purpose of this study is to investigate the long-term effects of participation in a cardiovascular screening program and of dietary counseling on self-reported psychosocial outcomes and health concerns. METHODS: High-risk subjects (n=563) with hyperlipidemia from the Oslo Diet and Antismoking Study (1972-1977) were reexamined after 25 years and randomly assigned to a new 3-year prospective 2x2 factorial placebo-controlled study in 1997 of n-3 polyunsaturated fatty acids and/or dietary counseling. Hospital Anxiety and Depression Scale (HADS), Life Satisfaction Index (LSI), and a new questionnaire on health concerns and behavior in response to risk information were collected at the 25-year follow-up. Hospital Anxiety and Depression Scale and LSI were evaluated at the end of the 3-year Diet and Omega-3 Intervention Trial on atherosclerosis (DOIT) in 505 subjects. RESULTS: Twenty-five years after the screening program, HADS-anxiety was similar to the Norwegian norms (3.3 vs. 3.5), while HADS-depression was significantly lower (3.6 vs. 4.1, P<.01). Patients reported that 25 years of awareness of hyperlipidemia had influenced health concerns through a moderate change in diet habits, some restriction in life conduct, but an improvement of the total life situation. After a novel 3-year intervention in DOIT, there was no difference between the dietary counseling and control group with regard to anxiety, depression, or life satisfaction, but HADS-anxiety increased significantly (4.0 vs. 3.3, P<.001) in both groups. CONCLUSION: Compared to the general population, screening-positive subjects did not have increased mental distress 25 years after screening, and beneficial health behavior persisted. Dietary counseling did not affect psychosocial outcomes.

Vitamin C consumption is associated with less progression in carotid intima media thickness in elderly men: A 3-year intervention study.

BACKGROUND AND AIM: Plant foods may lower the risk of cardiovascular disease. METHODS AND RESULTS: We assessed changes in the intima media thickness (IMT) of the carotid artery and diet in elderly men. Men (n=563) aged 70+/-5 years were randomly assigned to 1 of 4 groups (dietary intervention, omega-3 supplementation, both or neither) using a 2 x 2 factorial design. B-mode ultrasound of the carotid arteries and calculation of dietary intake were performed at baseline and after 3 years. We previously showed that omega-3 supplementation did not influence the IMT, thus the dietary intervention (n=233) and no dietary intervention (n=231) groups were pooled. The dietary intervention group had less progression in the carotid IMT compared with the controls (0.044+/-0.091 mm versus 0.062+/-0.105 mm; P=0.047). This group increased their daily vitamin C intake (P=0.005) and intake of fruit, berries and vegetables (P

Prevention of oil spill from shipping by modelling of dynamic risk.

This paper presents a new dynamic environmental risk model, with intended use within a new, dynamical approach for risk based ship traffic prioritisation. The philosophy behind this newly developed approach is that shipping risk can be reduced by directing efforts towards ships and areas that have been identified as high priority (high risk), prior to a potential accident. The risk model proposed in this paper separates itself from previous models by drawing on available information on dynamic factors and by focusing on the ship's surroundings. The model estimates the environmental risk of drift grounding accidents for oil tankers in real time and in forecast mode, combining the probability of grounding with oil spill impact on the coastline. Results show that the inherent dynamic risk introduced by an oil tanker sailing along the North Norwegian coast depends, not surprisingly, significantly upon wind and ocean currents, as well as tug position and cargo oil type. Results of this study indicate that the risk model is well suited for real time risk assessment, and effectively separates low risk and high risk situations. The model is well suited as a tool to prioritise oil tankers and coastal segments. This enables dynamic risk based positioning of tugs, using both real-time and projected risk, for effective support in case of a drifting ship situation.

Effect of diet or very long chain omega-3 fatty acids on progression of atherosclerosis, evaluated by carotid plaques, intima-media thickness and by pulse wave propagation in elderly men with hypercholesterolaemia.

BACKGROUND: This randomized study targeted a comparison of the effect of 3-year diet counselling or omega-3 polyunsaturated fatty acid (PUFA) supplementation (2.4 g/day) on the progression of atherosclerosis in carotid arteries and on finger pulse wave propagation. METHODS: Measurements were assessed by high-resolution B-mode ultrasound and a photopletysmographic finger pulse-sensor, respectively. Altogether, 563 elderly men with long-standing hyperlipidaemia were randomized into four groups: controls (no dietary counselling and placebo); dietary counselling (and placebo); omega-3 PUFA supplementation (no dietary counselling); dietary counselling and omega-3 PUFA supplementation. RESULTS: In the diet only group, the carotid intima-media thickness increase (0.929 to 0.967 mm) was significantly less than in the control group (0.909 to 0.977 mm), (P = 0.018). Significant increase in carotid plaques score and plaques area were observed in all four groups, but without between group differences. Changes in carotid intima-media thickness and in high-density lipoprotein-cholesterol were negatively correlated (adjusted P < 0.001). Pulse wave propagation time decreased significantly in the control group (206 to 198 ms; P = 0.002), reflecting reduced arterial elasticity. In the group receiving omega-3 PUFA only, pulse wave propagation time increased significantly when compared with the control group (P = 0.013). CONCLUSION: Reduced progression in carotid intima-media thickness was observed after dietary counselling, whereas omega-3 PUFA supplementation imposed a favourable effect on arterial elasticity.

Effect of diet and omega-3 fatty acid intervention on asymmetric dimethylarginine.

BACKGROUND AND AIM: Impaired vasodilatation has been suggested to be caused by inhibition of nitric oxide generation by the recently described asymmetric dimethylarginine (ADMA). In the present study we wanted to explore whether n-3 polyunsaturated fatty acid (PUFA) supplementation and/or diet intervention have beneficial influence on endothelial function assessed as plasma levels of ADMA and L-arginine. METHODS: A male population (n = 563, age 70 +/- 6 yrs) with long-standing hyperlipidemia, characterized as high risk individuals in 1970-72, was included, randomly allocated to receive placebo n-3 PUFA capsules (corn oil) and no dietary advice (control group), dietary advice (Mediterranean type), n-3 PUFA capsules, or dietary advice and n-3 PUFA combined and followed for 3 years. Fasting blood samples were drawn at baseline and the end of the study. RESULTS: Compliance with both intervention regimens were demonstrated by changes in serum fatty acids and by recordings from a food frequency questionnaire. No influence of either regimens on ADMA levels were obtained. However, n-3 PUFA supplementation was accompanied by a significant increase in L-arginine levels, different from the decrease observed in the placebo group (p < 0.05). In individuals with low body mass index (<26 kg/m2), the decrease in L-arginine on placebo was strengthened (p = 0.01), and the L-arginine/ADMA ratio was also significantly reduced (p = 0.04). CONCLUSION: In this rather large randomized intervention study, ADMA levels were not influenced by n-3 PUFA supplementation or dietary counselling. n-3 PUFA did, however, counteract the age-related reduction in L-arginine seen on placebo, especially in lean individuals, which might be discussed as an improvement of endothelial function.

Influence of long-term intervention with dietary counseling, long-chain n-3 fatty acid supplements, or both on circulating markers of endothelial activation in men with long-standing hyperlipidemia.

BACKGROUND: Dietary factors and very-long-chain n-3 polyunsaturated fatty acids (n-3 PUFAs) may influence the atherothrombotic process. Elevated concentrations of circulating cell adhesion molecules, thrombomodulin (TM), von Willebrand factor (vWF), and tissue-type plasminogen activator antigen (tPAag) are related to atherothrombotic cardiovascular disease. OBJECTIVE: The randomized Diet and Omega-3 Intervention Trial (DOIT) targeted a comparison of the effect of 3-y dietary counseling, n-3 PUFA supplementation (2.4 g/d), or both on circulating markers of endothelial activation. DESIGN: The study included 563 elderly men with long-standing hyperlipidemia. The men were randomly assigned by factorial design into 4 groups: control (no dietary counseling and placebo capsules), dietary counseling (and placebo capsules), n-3 PUFA supplementation (no dietary counseling), and dietary counseling and n-3 PUFA supplementation. RESULTS: Serum concentrations of fatty acids reflected good compliance. Dietary counseling was followed by significantly reduced concentrations of soluble intercellular adhesion molecule 1 (sICAM-1; P < 0.001), sTM (P = 0.004), and tPAag (P < 0.001) than in subjects without dietary counseling. After n-3 PUFA supplementation, significantly reduced concentrations of sICAM-1 (P < 0.001) and sTM (P = 0.006) were observed when compared with subjects receiving placebo capsules. An increase in tPAag was not significantly different from that observed in subjects receiving placebo capsules. For sICAM-1, a significant effect was observed for both interventions combined. CONCLUSIONS: Each intervention (dietary counseling or n-3 PUFA supplements) reduced sTM and sICAM-1 concentrations, indicating decreased endothelial activation. The tPAag increase in the groups not receiving dietary counseling (pooled), which indicates progression of atherosclerosis, was significantly counteracted by dietary counseling.

The effects of long-term diet and omega-3 fatty acid supplementation on coagulation factor VII and serum phospholipids with special emphasis on the R353Q polymorphism of the FVII gene.

The aim of the present study was to investigate the effect of long-term diet and very long chain n-3 fatty acids (VLC n-3) intervention on plasma coagulation factor VII (FVII), choline-containing phospholipids (PC) and triglycerides (TG), especially related to the R353Q polymorphism of the FVII gene. The present investigation included 219 subjects from the Diet and Omega-3 Intervention Trial on atherosclerosis (DOIT), a 2x2 factorial designed study in elderly men with long-standing hypercholesterolemia. The subjects were randomly allocated to receive placebo capsules (corn oil) (control), placebo capsules and dietary advice ("Mediterranean type" diet), VLC n-3 capsules, or VLC n-3 capsules and dietary advice combined. The R353Q genotype and the levels of FVIIc, FVIIag, FVIIa, PC, and TG at baseline and after 6 months were determined. Diet intervention was followed by a significant reduction of 5.1% in the levels of FVIIag and 2.4 mU/ml in FVIIa (95% CI -7.4, -2.9, and -3.8, -1.1, respectively) (both p<0.001) compared to the no diet group, independent of genotype. No effects of diet intervention on FVIIc, PC or TG were observed. After VLC n-3 supplementation the TG levels were significantly reduced compared to placebo (p=0.01), whereas all FVII levels and PC remained unchanged. Dietary advice towards a "Mediterranean type" diet, but not VLC n-3 supplementation, was shown to reduce the levels of FVIIag and FVIIa after 6 months, independent of genotype. The results indicate the dietary advice to be more favourable in reducing this risk factor for CVD as compared to specific VLC n-3 supplementation.

Dietary and antismoking advice and ischemic heart disease mortality in men with normal or high fasting triacylglycerol concentrations: a 23-y follow-up study.

BACKGROUND: In the Oslo Diet and Antismoking Trial, 1232 high-risk men aged 40-49 y were randomly assigned to either a lifestyle intervention group or a control group for 5 y. The study showed a significant reduction in ischemic heart disease (IHD) events in the intervention group. OBJECTIVE: Our objective was to examine this cohort 23 y after the start of the trial. DESIGN: We examined the effect of group assignment on IHD mortality in subjects with a normal (below the median; range: 0.69-2.00 mmol/L; n = 615) or a high (at or above the median; range: 2.01-13.80 mmol/L; n = 617) fasting triacylglycerol concentration in 1972-1973 (at inclusion into the study). We recorded vital status on 31 December 1996 and ascertained causes of death by linkage to Statistics Norway. RESULTS: In the men with a high triacylglycerol concentration, IHD death occurred in 25 (8.13%) subjects in the intervention group and in 44 (14.2%) subjects in the control group (relative risk: 0.57; 95% CI: 0.36, 0.91; P = 0.02). An adjusted Cox proportional hazards model yielded a hazard ratio of 0.56 (95% CI: 0.34, 0.93; P = 0.027). In the men with a normal triacylglycerol concentration, the intervention had no detectable effect on IHD mortality (adjusted hazard ratio: 1.10; 95% CI: 0.66, 1.83; P = 0.7). CONCLUSIONS: These data suggest that advice to change diet and smoking habits reduced the relative risk of IHD mortality after 23 y in men with high triacylglycerol concentrations. Men with normal triacylglycerol concentrations did not appear to achieve this long-term benefit of lifestyle intervention.