Fine Woody Debris in Morocco’s Coastal Environment: A Hidden Reservoir for Pollutants

Abstract

Marine debris is defined as any persistent, manufactured, or processed solid material that is intentionally or unintentionally disposed of or allowed to float into the marine environment. This debris can be of natural or artificial origin and includes a wide variety of materials, such as chemically treated wood. Fine woody debris (FWD), small particles with diameters ranging from 1 to 10 cm, can have natural and anthropogenic origin, which is often overlooked in coastal environments. In this study, we investigated FWD across multiple sites along the central Moroccan Atlantic coastline and identified 2068 FWD elements with an average density of 49.23 ± 38.07 items/m2. Site 2, near a river, stood out for its notably greater density, in contrast to the lower densities observed at the other sites. Chemical characterization of the FWD surfaces revealed mechanical abrasions, along with traces of heavy metals (HMs) such as Cu and Ti, plastics (including PS, PP, PE, PA, and PVC), and pharmaceuticals (periciazine, dipyridamole, and canthaxanthin). These findings underscore the role of FWD as a reservoir and transporter of environmental contaminants such as microfibers, and HMs, which can leach into surrounding waters and be taken up by marine organisms. The presence of these contaminants highlights potential disruptions to marine biodiversity and ecological processes, including bioaccumulation and toxicity in aquatic food webs, habitat degradation, and altered nutrient cycling. Moreover, the global significance of these findings lies in their implications for biodiversity management and conservation strategies. Anthropogenic FWD not only represents a source of pollution but also a vector for spreading harmful substances, emphasizing the urgent need for effective management strategies. These include regular monitoring and targeted cleanup efforts to mitigate potential hazards, preserve ecosystem integrity, and enhance recreational experiences in dynamic coastal environments.