Deliberate oil spill tests ecosystem’s response
KENORA, ONT. •Researchers were in northwestern Ontario over the weekend spilling diluted oilsands bitumen and crude oil into a lake to study how the ecosystem, from microbes to fish, responds.
The pilot project, known as Freshwater Oil Spill Remediation Study, is being done at the International Institute for Sustainable Development Experimental Lakes Area southeast of Kenora, Ont.
Vince Palace, the scientist who is leading the experiment, said the area is typically known for experiments involving a whole lake, but this work is different.
“We’re using small enclosures to contain that oil,” he said.
The oil was spilled inside four yellow, floating, boomed rectangles, each along 2.5 metres of shrub and sphagnum moss shoreline.
The enclosures stretch 10 metres into the lake and contain 20,000 litres of water. The spills were 1.25 litres each and were to be left for 72 hours then cleaned up by professional oil-spill responders.
With any oil spill, even after clean up, there is residual contamination.
“We’re interested in looking at the impact of residuals,” Palace said in an interview before the experiments were conducted.
Palace’s team will study impacts on microbes, algae, zooplankton, insects, wood frogs, and fathead minnows by sampling soil, water, and sediment before and after the spill and clean up.
They’ll look for direct impacts from fouling and poisoning, but also indirect effects on fish survival and reproduction. Palace notes that when oil spills, social pressure and regulatory commitments create a huge drive to clean it up.
“The problem is, in the shoreline environment, when you spill oil often times the removal of it can be just as damaging as the impact of the oil on the shoreline environment itself,” he said.
Soil removal, compaction, and moving heavy equipment into remote areas are ecologically destructive.
“In marine environments, there are microbes present that will respond to the presence of oil to degrade it. So it may be that there is a benefit to leaving the oil in place to degrade,” Palace said.
The researchers hope to find out if such oil-eating microbes exist in the freshwater environment of Boreal shield lakes. Diluted bitumen’s behaviour in freshwater has been studied extensively in laboratories.
Project collaborator Heather Dettman, senior scientist with Natural Resources Canada in Alberta, has simulated spills in laboratory wave tanks using North Saskatchewan River water.
Her studies have manipulated variables such as wave action and temperature, but not things like wind, rain and sun. So when it comes to understanding how oil behaves in a lake “maybe we’re missing something,” she said. This is “the next step up” from the lab.