Modelling and validation of polycyclic aromatic hydrocarbons emissions from offshore oil production facilities.

The development of numerical models for investigating the risks and impact caused by human activities to the marine environment is important. Herein, the recently developed ChemicalDrift Lagrangian dispersion model was coupled to a toxicokinetic model and applied to investigate emissions of polycyclic aromatic hydrocarbons (PAHs) discharged from oil and gas production facilities as produced water. The performance of the model was evaluated with available data from a monitoring survey conducted at two oil fields.

Mind the gap - Relevant design for laboratory oil exposure of fish as informed by a numerical impact assessment model.

Laboratory experiments provide knowledge of species-specific effects thresholds that are used to parameterize impact assessment models of oil contamination on marine ecosystems. Such experiments typically place individuals of species and life stages in tanks with different contaminant concentrations. Exposure concentrations are usually fixed, and the individuals experience a shock treatment being moved from clean water directly into contaminated water and then back to clean water.

Effects of Exposure Timing on Expression, PAH Elimination, and Lipid Utilization in Lumpfish Embryos Exposed to Produced Water.

Intentional discharges of produced water from oil production platforms to the marine environment contain a complex mixture of toxicants, including polycyclic aromatic hydrocarbons (PAHs). Early life stages of fish are highly sensitive to petrogenic exposure, and short-term exposure during critical periods of embryonic development may have detrimental effects on larvae health and survival. However, why different periods are more sensitive to exposure than others are not fully understood.

An impact-based environmental risk assessment model toolbox for offshore produced water discharges.

We present a novel approach to environmental risk assessment of produced water discharges based on explicit impact and probability, using a combination of transport, fate and toxicokinetic-toxicodynamic models within a super-individual framework, with a probabilistic element obtained from ensemble simulations. Our approach is motivated by a need for location and species specific tools which also accounts for the dynamic nature of exposure and uptake of produced water components in the sea. Our approach is based on the well-established fate model DREAM, and accounts for time-variable exposure, considers body burden and effects for specific species and stressors, and assesses the probability of impact.

An annual profile of the impacts of simulated oil spills on the Northeast Arctic cod and haddock fisheries.

We simulate the combined natural and pollutant-induced survival of early life stages of NEA cod and haddock, and the impact on the adult populations in response to the time of a major oil spill in a single year. Our simulations reveal how dynamic ocean processes, controlling both oil transport and fate and the frequency of interactions of oil with drifting fish eggs and larvae, mediate the magnitude of population losses due to an oil spill. The largest impacts on fish early life stages occurred for spills initiated in Feb-Mar, concomitant with the initial rise in marine productivity and the earliest phase of the spawning season.

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.

New insights into submarine tailing disposal for a reduced environmental footprint: Lessons learnt from Norwegian fjords.

Submarine tailing disposal (STD) in fjords from land-based mines is common practice in Norway and takes place in other regions worldwide. We synthesize the results of a multidisciplinary programme on environmental impacts of STDs in Norwegian fjords, providing new knowledge that can be applied to assess and mitigate impact of tailing disposal globally, both for submarine and deep-sea activities. Detailed geological seafloor mapping provided data on natural sedimentation to monitor depositional processes on the seafloor.

North sea produced water PAH exposure and uptake in early life stages of Atlantic Cod.

Produced water discharges from offshore oil and gas platforms represent a significant source of petroleum components such as polycyclic aromatic hydrocarbons (PAHs) released to the ocean. High molecular weight PAHs are persistent in the environment and have a potential for bioaccumulation, and the investigation of their fate and uptake pathways in marine life are relevant when assessing environmental risk of produced water discharges. To study the exposure and uptake of 2-5 ring PAHs in early life stages of Atlantic Cod in the North Sea, we run a coupled fate and individual-based numerical model that includes discharges from 26 platforms.

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).

On the use of random walk schemes in oil spill modelling.

In oil spill models, vertical mixing due to turbulence is commonly modelled by random walk. If the eddy diffusivity varies with depth, failing to take the derivative of the diffusivity into account in the random walk scheme will lead to incorrect results. Depending on the diffusivity profile, the result may be either over- or underprediction of the amount of surfaced oil.

Embryonic exposure to produced water can cause cardiac toxicity and deformations in Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) larvae.

Regular discharges of produced water from the oil and gas industry represents the largest direct discharge of effluent into the marine environment worldwide. Organic compound classes typically reported in produced water include saturated hydrocarbons, monoaromatic and polyaromatic hydrocarbons (MAHs, PAHs) as well as oxygenated compounds, such as phenols, acids and ketones. This forms a cocktail of known and suspect toxicants, but limited knowledge is yet available on the sub-lethal toxicity of produced water to cold-water marine fish species.

Improving oil spill trajectory modelling in the Arctic.

As petroleum development and other activities move further north, the potential for oil spills in ice-covered waters is of great concern. As a tool for contingency planning and forecasting during response, oil spill models play a key role. With the development of new, high-resolution coupled ice-ocean models, better predictions of sea ice are becoming available.

Toxicokinetics of Crude Oil Components in Arctic Copepods.

The risk of accidental oil spills in the Arctic is on the rise due to increased shipping and oil exploration activities, making it essential to calibrate parameters for risk assessment of oil spills to Arctic conditions. The toxicokinetics of crude oil components were assessed by exposing one lipid-poor (CIII) and one lipid-rich (CV) stage of the Arctic copepod Calanus hyperboreus to crude oil WSF (water-soluble fraction). Water concentrations and total body residues (BR), as well as lipid volume fractions, were measured at regular intervals during exposure and recovery.

Assessing impacts of simulated oil spills on the Northeast Arctic cod fishery.

We simulate oil spills of 1500 and 4500m/day lasting 14, 45, and 90days in the spawning grounds of the commercial fish species, Northeast Arctic cod. Modeling the life history of individual fish eggs and larvae, we predict deviations from the historical pattern of recruitment to the adult population due to toxic oil exposures. Reductions in survival for pelagic stages of cod were 0-10%, up to a maximum of 43%.

Automatic determination of heart rates from microscopy videos of early life stages of fish.

Toxic effects of organic hydrophobic contaminants include impacts on fish heart rate (HR) and cardiac functioning. Thus, in ecotoxicology as well as aquaculture and even medicine, fish heart functioning plays an important role in application areas. The aim of this study was to assemble a pipeline of image processing and statistical techniques to extract HR information from microscopy videos of the embryo and larval stages of three species of fish (Atlantic cod, haddock, and Atlantic bluefin tuna).

Dynamic Links between Lipid Storage, Toxicokinetics and Mortality in a Marine Copepod Exposed to Dimethylnaphthalene.

Efficiently assessing and managing the risks of pollution in the marine environment requires mechanistic models for toxic effects. The General Unified Threshold model for Survival (GUTS) provides a framework for deriving toxicokinetic-toxicodynamic (TKTD) models for the end point survival. Two recurring questions in the application of GUTS concern the most appropriate death mechanism, and whether the total body residue is a proper dose metric for toxic effects.

Modeling filtration of dispersed crude oil droplets by the copepod Calanus finmarchicus.

Oil droplets may form and disperse in the water column after an accidental spill of crude oil or petroleum products at sea. Micro-sized oil droplets may be available for filter feeding organisms, such as the copepod Calanus finmarchicus, which has been shown to filter oil droplets. In the present paper, a modeling approach was used to estimate potential ingestion amounts by copepod filtration of oil droplets.

Nonsequential two-photon double ionization of atoms: identifying the mechanism.

We develop an approximate model for the process of direct (nonsequential) two-photon double ionization of atoms. Employing the model, we calculate (generalized) total cross sections as well as energy-resolved differential cross sections of helium for photon energies ranging from 39 to 54 eV. A comparison with results of ab initio calculations reveals that the agreement is at a quantitative level.