Plastic pollution is widely recognized as a major threat to marine ecosystems due to its persistence and ubiquity across coastal and deep-sea environments. While the presence and distribution of marine litter have been extensively documented, a critical gap persists in understanding its ecological consequences at the population and community levels, particularly for macrozoobenthic assemblages. In particular, the role of plastic debris as an artificial substrate shaping biodiversity patterns, species interactions, and community structure remains poorly understood. ATTACH PhD project aims to address these knowledge gaps by investigating the colonization of plastic litter by macrozoobenthic communities across Mediterranean coastal and deep-sea ecosystems. The research is articulated into three case studies. The first examines communities associated with benthic plastic debris in the Capo Peloro coastal lagoon (Central Mediterranean Sea), comparing them with those colonizing natural substrates to assess differences in taxonomic composition, abundance, and structural complexity. The second adopts an experimental approach, involving the in situ installation of artificial substrates made of different polymers, to evaluate colonization dynamics over time and to unravel the influence of material properties on settlement patterns and community development. The third focuses on deep-sea muddy habitats, analyzing macrozoobenthic assemblages associated with plastic litter collected during MEDITS trawl surveys in the southern Tyrrhenian Sea (GSA 10), evaluating the role of plastic as potential available substrates for benthic organisms in deep marine habitats. By integrating observational and experimental approaches, the project seeks to answer key questions: 1) do plastic substrates support distinct benthic communities compared to natural ones? 2) how do colonization processes develop over time? 3) does polymer type influence community assembly? ATTACH will provide novel insights into whether plastic litter acts as a surrogate habitat or a novel ecological niche, contributing to a deeper understanding of its role in benthic ecology and informing future marine conservation strategies.