Buoyant plastic provides an ideal, well-lit surface on which algae can grow, and scientists have only just figured out that this is an issue. For years we have been finding dead pelagic seabirds filled with rubbish – as if they had chosen to eat it! The reason is horrifically simple: this type of seabird relies on scent to forage, and algae produce a fishy smelling compound that attracts and confuses these wide-ranging birds into consuming plastic, leading them to die.

Microscopic pieces of plastic pose a more complicated threat. Microbeads from personal hygiene and cleaning products and plastic microfibers from some synthetic fabrics are too small to be filtered out of urban and industrial wastewater and end up in the sea. Recent studies have found that many filter- feeding species and life forms, such as zooplankton and fish larvae, cannot discern between their natural food and microplastic. Ingesting microplastic negatively affects their development and may lead to smaller population numbers of species with planktonic life forms. As plankton form the base of the oceanic food web, this means that most species that rely on the sea (including us) may end up eating plastic-filled animals or experience a dwindling food source.