Oceans Time to Take out the Garbage: People May Be Familiar with Images of Individual Marine Animals and Birds Killed by Discarded Plastic Bags and Fishing Lines. but the Debilitating Effects of Marine Debris on Entire Species Is an Urgent Environmental Issue in the International Year of Biodiversity, as Christine Williams Discovered

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When the Plastiki--a boat made of 12 500 plastic bottles--arrived in Sydney in July, it alerted Australians to the impact of refuse on our oceans and sea life. In a statement congratulating the Plastiki crew, the United Nations Environment Programme (UNEP) noted that marine debris kills 100 000 turtles and other marine animals--dolphins, whales and seals--each year.

The UNEP statement also noted that if we collectively continue using the sea as a dustbin, 'human beings will soon have turned the once beautiful and bountiful marine environment from a crucial life-support system into a lifeless one'.

Ms Kim McKay, from Momentum 2 and the Sydney Institute of Marine Science Foundation, says the issue of marine debris has been a driver in her life since 1989, when she co-founded Clean Up Australia--now a worldwide movement--with Ian Kiernan. (1)

'The sad thing about the Plastiki voyage was that they didn't see many fish. They only caught four fish during the entire voyage,' she says.

Where does all the rubbish come from? Shipping is an obvious source. A UNEP report published in April 2009 cites a need for international agreements through national regulations for 'reception facilities for ship-generated wastes (including damaged fishing gear and nets) [and] cooperative action within the fishing sector to prevent abandonment and discarding of old fishing gear'. (2) A lot of rubbish also comes from unsustainable land-based waste disposal practices such as throwing away plastic water bottles.

Mr Doug Woodring, from Project Kaisei--a collaborative research initiative established to identify the scale of marine debris and its impact on the marine environment--says the project's mission is to prevent the increase of marine debris, to collect it sustainably and to enable its conversion into recyclable energy?

The project's current research is focused on the North Pacific, where one of five major gyres in the world spins a widening spiral of rubbish, estimated to be many thousands of square kilometres in size. Mr Woodring believes up to 80 per cent of ocean debris originates from land pollution.

'Governments have an obligation to use better practices to prevent this pollution, for example, when land waste products pour into the sea from river mouths during rainstorms,' he says. 'A solution to the problem lies in enforcing national laws, so polluters are fined if they flout laws that reflect moral and societal responsibilities. The way the laws of the sea are written means there's a focus on national boundaries and ocean-related business such as shipping lanes, industrial spills and fishing.'

Mr Woodring and his team--based in California and Hong Kong--are instead encouraging an international approach to tackling the problem of marine debris, with community engagement at the local level.

Plastic bags constitute a particular problem, as seals and other mammals can mistake them for jellyfish and consume them. Other plastics break down into small edible pieces, and the toxicology of their breakdown is little understood.

Having found plastic at depths of 200 metres during last year's expedition, the Project Kaisei team tested for chemical toxicity on molluscs and other sea life. This year, the team sent a vessel to verify modelling of where debris collects within the gyre. This required tracking thousands of GPS-equipped buoys.

Mr Woodring hopes plastic marine debris might be harvested using 'passive' systems such as nets and booms, while 'ghost nets' might be recovered through a reward system encouraging fishers to bring back nets to shore for waste-to-energy programs, which already happens to a small extent in the United States and Korea.

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According to a 2009 report on the impact of plastic debris on Australian marine wildlife, most records of impacts of plastic debris on wildlife relate to 'entanglement rather than ingestion'. …