What action breaks large plastic into microplastics?
Ultraviolet radiation photo-oxidises polymer chains, making exposed plastic brittle, while waves, sand abrasion, and repeated mechanical stress fracture it into progressively smaller pieces. This weathering generates secondary microplastics but usually does not mineralise the polymer fully. Acid rain is not the major marine fragmentation mechanism, and most organisms lack enzymes capable of rapidly digesting conventional plastics under environmental conditions. Because conventional polymers persist, fragmentation redistributes plastic into smaller pieces rather than removing its mass from the
Ref: Campbell Biology, Urry et al., 12th Ed., Unit 8 Ecology