title: Differentiating littering, urban runoff and marine transport as sources of marine debris in coastal and estuarine environments.
abstract: Marine debris is a burgeoning global issue with economic, ecological and aesthetic impacts. While there are many studies now addressing this topic, the influence of urbanisation factors such as local population density, stormwater drains and roads on the distribution of coastal litter remains poorly understood. To address this knowledge gap, we carried out standardized surveys at 224 transect surveys at 67 sites in two estuaries and along the open coast in Tasmania, Australia. We explored the relative support for three hypotheses regarding the sources of the debris; direct deposition by beachgoers, transport from surrounding areas via storm water drains and coastal runoff, and onshore transport from the marine system. We found strong support for all three mechanisms, however, onshore transport from the marine reservoir was the most important mechanism. Overall, the three models together explained 45.8 percent of the variation in our observations. Our results also suggest that most debris released into the marine environment is deposited locally, which may be the answer to where all the missing plastic is in the ocean. Furthermore, local interventions are likely to be most effective in reducing land-based inputs into the ocean.
authors.affiliation: Geography and Spatial Sciences, School of Land and Food, University of Tasmania, Hobart, TAS, 7001, Australia.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Willis
authors.affiliation: Commonwealth Scientific and Industrial Research Organisation (CSIRO) Oceans and Atmosphere, Hobart, TAS 7000, Australia.
authors.forename: Britta
authors.initials: B
authors.lastname: Denise Hardesty
authors.affiliation: Geography and Spatial Sciences, School of Land and Food, University of Tasmania, Hobart, TAS, 7001, Australia.
authors.forename: Lorne
authors.initials: L
authors.lastname: Kriwoken
authors.affiliation: Commonwealth Scientific and Industrial Research Organisation (CSIRO) Oceans and Atmosphere, Hobart, TAS 7000, Australia.
authors.forename: Chris
authors.initials: C
authors.lastname: Wilcox
mesh_terms: D063366:Estuaries; D005898:Glass; D006801:Humans; D008670:Metals; D015233:Models, Statistical; D010140:Pacific Ocean; D010209:Paper; D010969:Plastics; D012408:Rubber; D013648:Tasmania; D014866:Waste Products / Q000706:statistics & numerical data*; D014873:Water Pollutants / Q000032:analysis*; D014934:Wood
chemical_list: D008670:Metals; D010969:Plastics; D014866:Waste Products; D014873:Water Pollutants; D012408:Rubber