TEMPO.CO, Jakarta - A new study from Queen Mary University of London warns that much of the plastic floating in our oceans could take more than a hundred years to fully decompose.

The research sheds light on why plastic persists in marine environments and why cleaning it up is far more complicated than it seems.

These factors slowly break the plastic into smaller pieces, eventually producing microplastics.

Only the tiniest fragments, smaller than grains of sand, can sink. They attach to "marine snow," a sticky mix of organic material floating through seawater, which eventually carries the microplastics to the seabed.

Nan Wu, the lead author, explained that many people mistakenly believe plastic will sink or disappear quickly.

"People often assume that plastic in the ocean just sinks or disappears. But our model shows that most large, buoyant plastics degrade slowly at the surface, fragmenting into smaller particles over decades," she said.

Even after a century, he said, about 10 percent of the original plastic may still remain afloat.

"These tiny fragments can then hitch a ride with marine snow to reach the ocean floor, but that process takes time. Even after 100 years, about 10 percent of the original plastic can still be found at the surface," Wu added.

The research shows that even if plastic production stopped today, existing debris would continue to fragment and release microplastics for generations.

The study highlights that the rate of decomposition -- not sinking -- is the main factor in how long plastic remains in the ocean.

In century-long simulations, 10-millimeter plastic pieces almost entirely lost their mass, yet thin residues stayed afloat and continued generating microplastics.

Kate Spencer, co-author, said: "This is part of our wider research that shows how important fine and sticky suspended sediments are for controlling microplastic fate and transport."

Andrew Manning, lead scientist at HR Wallingford, explained that this research clarifies why the amount of plastic seen on the ocean surface does not match estimates of total ocean pollution.

"As large plastics fragment, they become small enough to attach to marine snow and sink. But that transformation takes decades," said Manning.

"Even after a hundred years, fragments are still floating and breaking down. To tackle the problem properly, we need long-term thinking that goes beyond just cleaning the surface."

The study underscores the importance of addressing plastic pollution at its source and planning for the long-term impact of microplastics in oceans worldwide.