Some naturally occurring lake bacteria have been shown to thrive more quickly and effectively on the remnants of plastic bags than on other organic materials like leaves and twigs. 29 European lakes were included in their analysis.
Bacteria break down the carbon compounds in plastic and utilize them as food to thrive.
According to the researchers, adding specific species of bacteria to water might be a natural approach to clean the environment of plastic pollution.
The result is clear: bacterial growth more than doubled when plastic pollution increased the overall carbon content in lake water by just 4%.
The research indicates that plastic pollution in lakes is probably "priming" the bacteria for quick development; as a result, the bacteria are more capable of breaking down other natural carbon compounds in the lake in addition to plastic.
It was discovered that lake bacteria preferred synthetic carbon compounds over natural ones. According to experts, this is because bacteria can more easily break down and consume the carbon molecules from plastics as food.
The researchers express caution: this does not support continuous plastic pollution. This is due to the fact that several chemicals included in plastics, especially at high quantities, can have hazardous effects on the environment.
The results were released in the journal Nature Communications today, July 26, 2022.
"It almost seems like the bacteria's hunger is being stoked by the plastic waste. "The bacteria use the plastic as food first because it is simple to decompose, and then they are better able to decompose some of the more challenging food - the natural organic matter in the lake," said Dr. Andrew Tanentzap, senior author of the paper and a professor at the University of Cambridge's Department of Plant Sciences.
"This shows that plastic pollution is enhancing the entire food chain in lakes, as more bacteria equals more food for the larger creatures like ducks and fish," he continued.
The outcome varied depending on the variety of bacterial species present in the lake water; lakes with a greater variety of species had better results in reducing plastic pollution.
The authors' work from the previous year revealed that microplastic contamination may be a problem in lakes throughout Europe.
Simple carbon molecules are released as polymers degrade. The scientists discovered that they are chemically different from the carbon molecules generated during the decomposition of organic stuff such as leaves and twigs.
It has been established that the carbon compounds in plastics come from additives that are specific to plastic goods, such as softeners and adhesives.
The current study also discovered that in lakes with less distinct natural carbon compounds, microbes cleaned more plastic pollution. This is because there were less additional food sources for the bacteria in the lake water.
The findings will aid in identifying which lakes need pollution management the most immediately. A lake's ecology will be more susceptible to harm if it contains high levels of plastic pollution but low levels of bacterial diversity and a wide variety of natural organic compounds.
"Plastics, unfortunately, will contaminate our ecosystem for decades. On the plus side, our research identifies bacteria that may be used to break down plastic trash and better control environmental pollution, according to Professor David Aldridge of the Department of Zoology at the University of Cambridge, who participated in the study.
Between August and September 2019, 29 lakes in Scandinavia were sampled for the study. These lakes varied in latitude, depth, area, average surface temperature, and variety of dissolved carbon-based molecules to evaluate a variety of situations.
Four big UK retail companies' plastic bags were disassembled by the scientists, who then shook them in water to release carbon compounds.
Glass bottles were filled with lake water at each lake. To symbolize the quantity of carbon leached from plastics into the environment, a little amount of "plastic water" was added to half of these, and the same amount of distilled water was added to the other half. Bacterial activity was assessed in each bottle after 72 hours in the dark.
The amount of carbon dioxide emitted during the growth phase was used in the study to gauge both the efficiency and increase in mass of the bacteria.
The bacteria had effectively doubled in bulk in the water containing carbon compounds generated from plastic. In just 72 hours, the bacteria absorbed almost 50% of this carbon.
"Our study demonstrates how the introduction of plastic bags into lakes and rivers may have profound and unanticipated effects on the ecosystem as a whole. Eleanor Sheridan, an undergraduate student in her last year at the University of Cambridge's Department of Plant Sciences, is the study's primary author. She hopes that the findings will motivate people to be even more cautious about how they dispose of plastic garbage.
