Marine litter helps the spread of invasive alien species


Wednesday, 22 March 2017

A JRC led report highlights the damages and related costs caused  by macro and micro plastic to marine ecosystems, human health and economic activities.  In addition to the pollution of sea, marine litter could also help the spread of invasive alien species. The invasion of seas by non-indigenous species is one of the greatest drivers of biodiversity loss, posing a threat to the integrity and functioning of ecosystems. Non-indigenous invasive species often use litter in the ocean as a habitat in which to hide, as a platform on which to settle or as a transport medium for moving into new territories.

This is not a new phenomenon, as natural debris (dead wood, ash, etc.) have enabled species to move around for millions of years, but the movement of alien species on litter items is potentially a new problem, because of the proliferation of floating – mostly plastic – particles. The estimated 250 billion micro-plastic particles floating in the Mediterranean Sea are all potential carriers of non-indigenous invasive species. Plastic litter offers an excellent transport mechanism for alien species because of its longevity at sea and its surface, which is easy to attach to. Even if the introduction of large litter items into the marine environment ceased, the abundance of micro-plastics would continue to increase because of the fragmentation of the existing plastic items.

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Picture © H. Gladier