Researchers find massive microplastic hotspots on the deep seafloor

Every year, plastic waste discarded by humans — everything from plastic straws and food packaging to fishing nets and industrial products — ends up in the oceans. This trash floats around, eventually bumping into each other, where it becomes trapped and forms an 'island' of trash. A new study sheds light on what happens to this plastic over time, namely the microplastic hotspots it can produce.

Microplastics are small — often microscopic — bits of plastic that have broken free from larger pieces over time; examples include plastic fibers released from synthetic clothing and that scrape free of larger materials like barrels and nets. These microplastics have been found in drinking water and even in fish, raising concerns about both their environmental and health impact.

A new study out of the University of Manchester reveals the discovery of where this plastic pollution ends up. Researchers describe 'huge sediment accumulations' of microplastics, areas they've dubbed hotspots. The study compares microplastic hotspots on the deep seafloor with the floating islands of trash that have formed on the ocean's surface.

The discovery reveals that these microplastics aren't uniformly dispersed across the ocean floor, but rather that they tend to build up in certain areas, a process made possible by riding currents along the seafloor. Unfortunately, these same currents also carry nutrients and oxygenated water, making the hotspots ecosystems where creatures may end up ingesting the plastic particles.

The study found that most of the microplastics in these hotspots are sourced from clothes and textiles; the fibers may be, for example, pulled from fabrics when clothes are washed, eventually making their way into rivers and oceans. The findings were based on deep ocean current models and data on sediment samples collected from the Tyrrhenian Sea.