Testing indicators for biological impacts of microplastics .

The EU is still far from its goal of achieving healthy seas and part of the problem is due to marine litter (European Commission, 2014). Plastic materials invariably make up the dominant fraction of marine litter and there are particular concerns regarding the impacts of plastic microlitter (plastic particles in the range of a few nanometers up to 5 mm). The small size, persistence and ubiquity of these ‘microplastics’ in both pelagic and benthic ecosystems means they have the potential to be ingested, along with naturally occurring particulate matter, by a wide array of marine biota with unknown consequences for Darwinian fitness parameters (growth, survival, performance, reproduction). Due to the varying size, buoyancy and composition of marine litter, ingestion will vary for litter types between feeding guilds; planktivores and filter feeders will encounter low-density litter fragments suspended in the upper water column whereas high density litter fragments are more likely to be available to deposit feeders and detrivores. Important research gaps remain for the implementation of the Marine Strategy Framework Directive (MSFD) over the suitability of different species for evaluating microplastics impacts across the four main seas regions of Europe. These gaps include the composition of ingested litter, its propensity for retention within the gut, leaching of associated chemicals, translocation within body tissues and transfer through generations and/or the food web. One of the aims of the CleanSea project task is to provide fundamental scientific knowledge on the scale and nature of the physical and chemical impacts of marine litter, and in particular microplastics, on exemplar marine organisms and the predicted consequences for populations and communities. We aim to determine the impact of this type of marine litter on population-relevant fitness parameters and energy budgets in key species, with a focus on the base of the marine food web. In CleanSea, the main species under study include algae, bacteria, invertebrates such as zooplankton, sponges, echinoderms, bivalves and crustaceans, as well as fish and birds. Here we present a summary update on progress on determining the ecological harm of microplastics and discuss important aspects of indicator species selection that Member States will be confronted with when implementing the Marine Strategy Framework Directive (MSFD)