Palace and his colleagues wanted to see if leaving the oil in place to be cleaned by natural processes like bacteria could be a practical alternative.
“We know that in the marine environment there are bacteria that can break down oil,” Palace said. “We wanted to know if naïve freshwater systems have the same capacity.”
Researchers created enclosures along the shore of one of the experimental lakes and dumped either conventional crude oil or diluted bitumen from Canada’s tar sands to simulate a spill. After 72 hours, they cleaned it off as best they could, then looked at what had happened to the residual oil over the summer and winter.
The team found that after the spill, the composition of the bacterial community in the soil and water had changed dramatically. Rare types of bacteria, which were barely present before, suddenly became the most common – and most of them had the ability to break down oil using it as a food source, suggesting that a recovery natural could be a potential solution to local spills. like the Great Lakes, which are crisscrossed by pipelines and are home to several refineries.
Currently, Enbridge Inc.’s Line 5 under the Straits of Mackinac and Line 3 across Minnesota and Wisconsin are sources of controversy as residents and activists worry about the potential ramifications of an oil spill from either of the pipelines.
However, it is not yet clear what effect such a drastic change in the makeup of the bacterial community could have on the wider ecosystem.
Zhanfei Liu, a chemist at the University of Texas at Austin who has studied the response of bacterial communities in the Gulf of Mexico to the Deepwater Horizon oil spill, said he was not surprised to see an increase in bacteria degrading the oil in freshwater ecosystems. Although people tend to think that the microbial community in the Gulf of Mexico, with its thousands of naturally occurring oil seeps, is particularly suited to processing oil, Liu says this is a misconception – this ability is present in ecosystems everywhere.
“Mother Nature is ready to act,” he said. “If you spill oil anywhere, you’re going to see the oil degraders take off.”
The next step for Palace and his team is to do more specific experiments on how, exactly, bacteria break down oil, whether they react differently to the two types of oils, and how quickly they act. This will help determine if leaving most of the cleaning work to bacteria is a viable solution.
The biggest obstacle, he said, is public perception: people just don’t like the idea of letting nature clean up our mess. While Palace does not yet approve of leaving the spill cleanup to bacteria, he hopes this work can help address some of those concerns.
“We are trying to provide the scientific data that can tell us if this is a valid approach,” Palace said. “We’ve seen enough so far to say it’s at least worth further evaluating.”