title: Debris size and buoyancy influence the dispersal distance of stranded litter.
abstract: Recent at sea surveys of floating macro-debris in the southeast Atlantic Ocean found that debris increases in size with distance from shore, suggesting that many smaller items, which dominate litter close to urban source areas, sink before dispersing far into the ocean. We test whether this pattern is evident in beach litter in the same region. Freshly stranded beach litter was collected at increasing distances (0km, 100km, 200km and 2800km) from Cape Town, a major urban litter source. Mean size and buoyancy of litter items increased significantly with distance from Cape Town. Size-specific sedimentation due to the ballasting effect of biofouling is a plausible explanation for the disappearance of smaller, less buoyant items. Our results provide further evidence that many low buoyancy items sink and support the hypothesis that size and buoyancy are strong predictors of dispersal distance for floating debris.
authors.affiliation: Percy FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch 7701, South Africa. Electronic address: francescafazey@gmail.com.
authors.forename: Francesca M C
authors.initials: FMC
authors.lastname: Fazey
authors.affiliation: Percy FitzPatrick Institute of African Ornithology, DST-NRF Centre of Excellence, University of Cape Town, Rondebosch 7701, South Africa.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Ryan
mesh_terms: D001267:Atlantic Ocean; D001493:Bathing Beaches; D057219:Biofouling; D004784:Environmental Monitoring / Q000379:methods*; D010969:Plastics / Q000032:analysis; D013019:South Africa; D014866:Waste Products / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D010969:Plastics; D014866:Waste Products; D014874:Water Pollutants, Chemical
keywords: Biofouling; Dispersal; Flotation; Marine debris; Microplastics; Size; South Africa; South Atlantic