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Wednesday, 24 April, 2002, 22:16 GMT 23:16 UK
Rubbish menaces Antarctic species
Marine debris on beach, BAS
Debris like this washes up on Antarctic shorelines
(Image: British Antarctic Survey)

Man-made debris floating across the sea is offering species a lift into new habitats, threatening the ones that already live in places like Antarctica.

David Barnes of the British Antarctic Survey says floating plastic provides a vehicle for marine organisms like barnacles, worms and molluscs to travel much further than they would normally.

His study, published in the journal Nature, says many species seem to prefer man-made rubbish to natural debris like volcanic rock, pumice and wood.

Marine life on plastic, BAS
Tiny pieces of plastic provide a crowded home
Half of all marine rubbish in the tropics is man-made, with the proportion far higher close to Antarctica, where there are no forests to provide natural flotsam, he says.

The kinds of organisms found on litter are not just species like barnacles, which commonly attach to the bottom of ships.

"There are weedy species a bit like cold water corals, together with more familiar species like molluscs and bivalves," Dr Barnes told the BBC.

Marine life has used natural debris to spread and colonise new habitats for millions of years.

Marine life on plastic, BAS
Some species even prefer it to natural flotsam
"Most of these organisms would be able to disperse anyway by larvae," he said.

"But larvae travel for relatively short distances. They wouldn't be able to invade areas which are too different from the areas that they live in.

"But when larvae settle on to plastic, they metamorphose into adults and as adults they can survive much harsher ranges of conditions," he said.

Double threat

Human rubbish spreads across all the world's seas, forming half of all the marine debris washing up in the tropics and more at higher latitudes.

Antarctica is one of the places which is most threatened

David Barnes
Around Antarctica, the total amount of debris is low, but the proportion of it due to humans is very high.

The continent could be at particular risk from alien species floating in because of a double threat from global warming and a lack of alternative habitats for many of its species.

Outside organisms floating in could benefit from warmer conditions and displace the indigenous species, many of which do not occur anywhere else in the world.

"There has always been marine debris in the form of pumice, volcanic rock, coconuts and so on [but] we are greatly increasing something that was already there.

"Antarctica is one of the places which is most threatened," Dr Barnes said.

He and his colleagues are continuing research into the effects of this increased migration.

The BBC's Graham Satchell
"Marine organisms are hitching a ride on bits of rubbish"
David Barnes of the British Antarctic Survey
"What surprised me the most was the level of waste which was due to people"
See also:

09 Apr 02 | Arts
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29 Mar 02 | Sci/Tech
New images of iceberg breakaway
13 Jan 02 | Sci/Tech
Wildlife risk as Antarctic cools
18 Dec 01 | Sci/Tech
Warmth puts penguins under pressure
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