Anthropogenic marine debris in the coastal environment: a multi-year comparison between coastal waters and local shores.

Anthropogenic marine debris (AMD) is frequently studied on sandy beaches and occasionally in coastal waters, but links between these two environments have rarely been studied. High densities of AMD were found in coastal waters and on local shores of a large bay system in northern-central Chile. No seasonal pattern in AMD densities was found, but there was a trend of increasing densities over the entire study period. While plastics and Styrofoam were the most common types of AMD both on shores and in coastal waters, AMD composition differed slightly between the two environments. The results suggest that AMD from coastal waters are deposited on local shores, which over time accumulate all types of AMD. The types and the very low percentages of AMD with epibionts point to mostly local sources. Based on these results, it can be concluded that a reduction of AMD will require local solutions.