Litter clean-ups will not solve the marine plastics crisis The ecological, technical, and economic constraints of seabed clean-ups © OCEANA
December 2022 Coastal clean-up movements to counter waste littered in the environment have become widespread. Such clean-ups (including ‘fishing-for-litter’ schemes) are increasingly included in European Union government policies and programmes as one of the solutions for mitigating the impacts of marine litter, mostly within the context of the EU Marine Strategy Framework Directive.1 Despite their growing popularity, however, such clean-up measures are not a viable means of addressing the immense problem of underwater plastic pollution. In recent decades, great strides have been made in improving at-sea exploration technology, some of which may be applied to at-sea clean-up efforts. Some initiatives to collect floating litter have gained extensive media and public attention, as well as funding. Emerging devices have been seen as potential tools to collect litter, but they have failed to consider a key point: most plastics lie on the seabed. Globally, 80 % of marine litter items are made of plastic2 and the vast majority of this waste lies on the seabed.3 It is estimated that floating plastic may represent as little as 0.2 % of the total plastic input to the sea, while most of the non-fibrous plastics buried
in marine sediments have been found at depths of between 200 m and 2000 m.4 Clearly, most clean-up efforts – which focus on removing plastic litter from beaches and shallow waters – can do very little to remove most of the plastic that enters the ocean.
Clean-up projects have led the wider public to believe that the problem of ocean plastic pollution is easily fixed, which has also likely resulted in delayed government actions to address the root causes (e.g., excessive packaging, overuse of single-use plastics, and littering). However, the limitations of seabed clean-ups show that these approaches cannot be used as a justification to continue with a business-asusual scenario of plastic production. Here, we provide a brief overview of the limitations of clean-up technologies, based on a more comprehensive research study commissioned by Oceana.5
Ecological limitations: damage to vulnerable ecosystems Litter accumulation on the sea bottom can be influenced by a range of factors, such as geomorphological features of the seabed, and by litter size and density. For example, seafloor litter tends to accumulate in “plastic traps”, such as seamounts, canyons, and other areas characterised by rugged topography.6,7,8
Litter becomes entangled in benthic habitats such as cold-water coral reefs and sponge aggregations.9,10 Such habitats are particularly vulnerable to physical impacts,11 and efforts to remove entangled plastics from these systems may cause damage, ranging from habitat destruction to disturbance of ecosystem functioning. Clean-ups should 1