Plastic. There should be hundreds of thousands of tonnes of the stuff floating around in our oceans. But we are finding less than expected – perhaps because living organisms are evolving the ability to break it down.
(From New Scientist / by Michael Le Page) — Plastic production is rising exponentially, so ever more of it should be ending up in the oceans, says Ricard Sole, who studies complex systems at the Universitat Pompeu Fabra in Barcelona. But surveys of areas where floating plastic accumulates, such as the North Atlantic gyre, are not finding nearly as much plastic as expected.
In fact, there’s only a tenth to a hundredth as much plastic as expected – and the amount of floating plastic does not appear to be increasing. “The trend should be there,” Sole says.
This lack of trend cannot be explained by physical processes, according to his team’s mathematical models. Instead, they propose that there has been a population boom in microbes that have evolved the ability to biodegrade plastic.
Surprisingly, even if ocean plastic is being degraded much faster than thought, it is not clear that this is a good thing. “It is difficult to say,” says Matthew Cole of Exeter University in the UK.
For instance, biodegradation could be speeding up the breakdown of large pieces of plastic into lots of very tiny pieces, which might have a greater overall impact.
Plastic also contains various additives that could get released and enter the food chain if the plastic part biodegrades, says environmental chemist Alexandra ter Halle of the Laboratoire des IMRCP in France.
“To really tackle the plastic problem, we need to stop it getting into the oceans in the first place,” Cole says.
Read the full article here: https://www.newscientist.com/article/2132650-newly-evolved-microbes-may-be-breaking-down-ocean-plastics/