Bacteria may hold the key to addressing plastic lake pollution

Story at a glance

  • Analyses of water samples from 29 lakes in Scandinavia highlight the potential of certain bacteria to combat plastic pollution.

  • The bacteria feed upon carbon compounds found in plastic bags. 

  • Researchers hope the findings will help identify and prioritize the most affected bodies of water.

Plastic pollution in lakes can lead to a myriad of environmental concerns for native plants and wildlife. But new research from the University of Cambridge points to bacteria as a potential natural solution to this problem.

Previous research has suggested other organisms, like worms, also have the capability to break down plastics. 

After investigating nearly 30 lakes across Scandinavia in 2019, the team of researchers found some bacteria that occur naturally have an appetite for the carbon compounds in plastic bags. When compared with leaves and twigs, these bacteria actually grew faster and more efficiently on the waste diet.

Plastic pollution that raised water carbon levels by 4 percent resulted in more than two times the rate of bacteria growth, researchers found.

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The increased efficiency seen is due to the more accessible added carbon in the bags (like adhesives and softeners) than that in natural organic matter, authors wrote, noting bacterial diversity within lakes also factored into efficiency, as lakes with more varied species were better at breaking down the pollution. 

Bacteria were also more successful  at removing plastic in lakes with fewer natural carbon compounds due to fewer food options.

“Together, our results suggest that plastic pollution may stimulate aquatic food webs and highlight where pollution mitigation strategies could be most effective,” they said. 

Furthermore, after the bacteria successfully broke down the plastic, they then were better equipped to break down additional natural carbon in the water. “It’s almost like the plastic pollution is getting the bacteria’s appetite going,” said study co-author Andrew Tanentzap in a press release.  

“This suggests that plastic pollution is stimulating the whole food web in lakes, because more bacteria means more food for the bigger organisms like ducks and fish,” he added. 

But researchers caution the findings do not support increased plastic pollution in lakes, as additional plastic compounds can have toxic environmental ramifications. 

“Hopefully our results will encourage people to be even more careful about how they dispose of plastic waste,” added co-author Eleanor Sheridan.