Plastics never fully decompose, so when they break down, what's left is microplastic: tiny particles with a diameter that ranges from about the width of a sesame seed down to that of a single human hair.
On board the ship, scientists periodically drop a net in the water to capture and count microplastics in the patch. They leave the net in the waves for a half hour at a time, and Lecomte said the crew captures around 36 plastic pieces every minute.
"And that is just an average," he said. "Our biggest tow has been over 3,000 pieces in 30 minutes."