“The Gulf of St Lawrence is under immediate pressure for oil and gas exploration, particularly at the Old Harry prospect, and there is extensive public concern about the risk of spills and coastal contamination,” Dumont told environmentalresearchweb. “Yet to date there is very little independent scientific research on the fate of oil spills from this offshore region.”

Using surface current forecasts from the Department of Fisheries and Oceans Canada, Dumont and colleagues Daniel Bourgault, also of the Université du Québec à Rimouski, Angela Carter of the University of Waterloo, Canada, and Frédéric Cyr from the Royal Netherlands Institute for Sea Research looked at how far an inert substance such as a coloured dye released at Old Harry would spread horizontally.

The researchers found that this floating passive tracer was likely to follow two dominant paths – one spreading towards the northwest, along the French Shore of Newfoundland, and the other moving along the southwest-northeast axis of the Laurentian Channel. To simplify their model, the team ignored any degradation or transformation that might take place in the ocean for a more changeable substance such as oil. They published their results in Environmental Research Letters (ERL).

“Assuming conservative properties of the released substance, it [the model] also implied a high probability for coastal contamination particularly in Cape Breton and along the French Shore of Newfoundland within three weeks of a surface spillage,” said Dumont. “In a recent comment, Boufadel and Geng (2014) regarded this simplified approach as being a reliable screening tool for decision-making but pointed out that the results would be even more relevant if supplemented by real data.”

That’s where the TV crew was able to help. When Pier Gagné and Jean-Pierre Rogel from Radio-Canada’s Découverte science programme chartered a fishing vessel to visit Old Harry and take footage for a future show, Dumont suggested that the two journalists launch three surface drifters at the Old Harry site to find out how well his model represented the situation on the ground (or rather, in the sea).

Launched by the journalists early in the morning of 29 June, the surface drifters washed up near the community of Port Saunders in Newfoundland on 11 July. According to Dumont, the paths they followed provide three important insights into the team’s models.

“The three buoys headed northwest along the French Shore of Newfoundland, taking one of the two pathways predicted by the numerical study,” he said. “Second, the buoys travelled through numerous areas recently acknowledged as ‘sensitive and protected’ by the Western Newfoundland & Labrador Offshore Area Strategic Environmental Assessment (WNL-SEA) Update Final Report. The path taken suggests that oil from a spill at the Old Harry site could pass directly through the habitat of marine species at risk and key sites for the fishing industry, and alongside sensitive shorelines and important regions for the tourist industry, including Gros Morne National Park, a UNESCO World Heritage Site.”

The third insight is that the buoys travelled far faster – and reached land sooner – than anticipated by Dumont, Bourgault and the rest of the team’s model. The drifters travelled 380 km in 12 days, at an average drift speed of 40 cm/s. “In comparison, the simulations of Bourgault et al. that did take into account the wind drift but only the current averaged over the first few metres, predicted that it would typically take 20 to 30 days for water to reach this landfall,” he added. “Drifter data thus reveal that oil may possibly reach land before it could be significantly evaporated, dispersed or consumed by bacteria given this cold-water environment.”

The buoys also clustered together as they drifted, staying within 10 km of each other even during the passage of Tropical Storm Arthur on 6 July. “The limited horizontal dispersion along the trajectory suggests that if an oil spill had occurred at the period the drifters were released it would likely not have been significantly horizontally dispersed prior to contaminating coastal areas,” said Dumont.

The researchers believe that these new but still limited observations support public concerns about coastal contamination. “More in-depth multidisciplinary research is needed to understand better the potential impact of oil spills in the Gulf of St Lawrence,” said Dumont. “A number of initiatives led by ISMER [Institut des Sciences de la Mer, Université du Québec à Rimouski] are currently underway to address these knowledge gaps and provide scientific data to inform policy decisions on offshore oil activities.”

• The Découverte show regarding Old Harry will air on Sunday October 26th at 18:30 EST.

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