Report of the 5th meeting of the Network of Experts for ReDeveloping Models of the European Marine Environment

The fifth workshop of the ‘Network of Experts for ReDeveloping Models of the European Marine Environment’ was held on 28-29 November 2022 in Ispra, Italy, jointly organized by DG Environment and DG JRC (Water and Marine Resources Unit) within the framework of the Administrative Agreement “Model development and operation in the context of the Marine Strategy Framework Directive implementation cycle (BLUE2-2020-2023)". The aim of this workshop was to discuss with the wider scientific community the methodologies, tools, datasets and approaches more appropriate to: (i) simulate the quantity, distribution and accumulation of plastic litter in the ocean (both micro and macro plastics) and (ii) assess the potential impact of incorporation and transference of micro plastics in the marine food webs. The workshop was organized over two days, each dedicated to one of the topics. Presentations were followed by extensive discussions on each of the following questions/issues: (i) what elements should be included in Lagrangian models to correctly simulate the behaviour of plastic litter at sea?, (ii) How can we estimate the inputs of plastics into the marine environment?, (iii) What datasets exist about plastic pollution, and how to harmonize monitoring and model data? and (iv) How to best align estimates of plastic debris distribution with marine ecosystems models? This report compiles the discussions held and presents proposal encompassing best practices on how to tackle the issue of ‘plastic modelling at sea’.