The Great Pacific Garbage Patch spans roughly 1.6 million km² — twice the size of Texas. Ocean gyres act as convergence zones, concentrating buoyant debris. UV radiation and mechanical wave action fragment macroplastics into microplastics (<5mm), which are mistaken for food by marine organisms. Plastics bioaccumulate through the food web, concentrating toxins at each trophic level. An estimated 8 million tonnes of plastic enter the ocean annually, with current stock exceeding 150 million tonnes.