Certain lake bacteria found to help in fight against plastic pollution

Researchers have discovered that certain lake bacteria in 29 different Scandinavian lakes grow quicker and more efficiently on the remains of plastic bags than on natural matter like leaves and twigs.

This presents a potential natural solution to tackling plastic pollution, as the bacteria break down compounds in the plastic and eat them for growth.

Scientists found the rate of bacterial growth more than doubled when plastic pollution raised the overall carbon level in lake water by just 4%.

They suggest that plastic left in waters ‘primes’ bacteria for rapid growth, meaning they can break down other natural carbon compounds in the lake, as well as plastic.

‘It’s almost like the plastic pollution is getting the bacteria’s appetite going. The bacteria use the plastic as food first, because it’s easy to break down, and then they’re more able to break down some of the more difficult food – the natural organic matter in the lake,’ said Dr Andrew Tanentzap in the University of Cambridge’s Department of Plant Sciences, senior author of the paper.

‘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.’

Lake bacteria was found to prefer plastic-derived carbon compounds over natural compounds, potentially because they are easier for the bacteria to break down and digest.

However, while plastic seems to benefit these species of bacteria, scientists say this doesn’t condone plastic pollution, as it can have toxic effects on environments, especially at high concentrations.

But adding certain bacteria to waters could help to remove plastic, as the study found effects varied depending on the diversity of bacteria in each lake – the more diverse, the better the bacteria was at breaking down plastic pollution.

Additionally, bacteria ate more plastic when there were fewer unique natural carbon compounds in the water, as there were fewer food sources to choose from.

The study will help scientists to prioritise which lakes needs urgent action, as a lake with a lot of plastic pollution, low bacterial diversity and a lot of different natural organic compounds will be more vulnerable to damage.

‘Unfortunately, plastics will pollute our environment for decades. On the positive side, our study helps to identify microbes that could be harnessed to help break down plastic waste and better manage environmental pollution,’ said Professor David Aldridge in the University of Cambridge’s Department of Zoology, who was involved in the study.

The findings were published in the journal Nature Communications.

Photo by Lennard Kollossa