Plastic accumulation at key interfaces

Institute of Marine Sciences of the National Research Council of Italy (CNR-ISMAR), Italy

 

Title: Moving plastics on ocean's surface

 

Abstract: Floating marine plastic debris poses a significant environmental challenge. Gaining a deeper understanding of how plastic is transported from coastal and marine sources is essential to quantify and address the global distribution of marine plastics and properly develop dedicated policies. Moreover, plastic serves as a distinctive tracer, offering valuable insights into ocean physics and dynamics across various scales—from Ekman convergence in large-scale ocean gyres to the behavior of individual waves in coastal surf zones.

 

Here we present the fundamental processes that influence the transport of floating marine plastic debris in both the open ocean and coastal regions. Drawing from the existing literature and related fields such as oil spill dispersion, marine safety and recovery, and plankton connectivity, we explore the mechanisms at play. Additionally, we highlight the role of in situ and laboratory measurements, remote sensing, and numerical simulations in advancing our understanding of these processes and their interactions across spatial and temporal scales.

 

Norwegian Institute for Water Research (NIVA), Norway

 

Title: The role of plastic pollution in altering ecosystem exchanges at water-air and sediment-water boundaries: current status and future directions

 

Abstract: Plastic represents a novel and persistent environmental entity which can impacts the water environments in several direct and indirect ways. Plastic materials not only persist in the environment but also serve as substrates for biofilm formation, carrying distinct microbial communities. Such biofilms can significantly alter essential exchanges of nutrients, organisms, and energy at key environmental boundaries in which plastic strongly accumulates (i.e., air-water and sediment-water interfaces). These alterations can have important, ecosystem-level implications, such as the altered microbial community functioning and the alteration of key biogeochemical cycles of major and minor nutrients.

 

Current research in this area remains fragmented, but emerging evidence highlights the potential for plastics to alter gas exchanges at key interfaces, reshape microbial community favoring the dispersal of allochthonous species and potentially alter light and heat influx. Future studies should prioritise the environmental relevance of these interactions, focusing on how the persistence, mobility, and unique characteristics of plastics drive changes in natural exchange rates and ecological processes at these interfaces. This holistic understanding is critical for assessing the full scope of the risks posed by plastic pollution in aquatic environments.