Turtle power –
New explanation for why sea predators are eating so much plastic
A paper published in Current Biology this week has an alternative explanation: it’s the smell of plastic, not the look, that attracts turtles . Rather, it’s the smell of organisms that latch on to the plastic. The authors found that turtles were attracted to the smell of plastic coated in goopy ocean organisms just as much as they were attracted to the smell of food. That’s useful information for starting to figure out how to mitigate the effects of ocean plastic on predators like turtles.
Delicious stinky plastic
Plastic floating around in the ocean pretty quickly gets gooped up by all kinds of organisms that start to grow on them. This “biofouled” plastic has been
found to emit dimethyl sulfide, an organic compound that
plankton releases in larges quantities . Animals use this smell as a signal that food may be present, and seabird species that rely on this as a food cue have been shown to ingest more plastic than species that use the smell cue less.
Still, that’s just one piece of evidence suggesting that smell is an important explanation of ocean plastic consumption. Turtle biologist
Joseph Pfaller and his team wanted to look for a second piece of evidence by testing experimentally whether turtles responded to plastic in the same way they did to food.
Taken along with the evidence on bird plastic consumption, this result offers a second piece of evidence that smell plays an important role in animals ‘attraction to plastic. Because the researchers only used a small number of turtles, so their results will need confirmation through more studies in the future to be sure that the data was too noisy to give a reliable result.
Still, the results have the advantage of explaining something that otherwise makes no sense: why turtles and other sea creatures are chowing down on Such a huge variety of plastic, not just the kinds that might look like prey. More work exploring this explanation could help to build a better understanding of how animals are interacting with plastic — and how to stop them from being killed by it.
(Current Biology) , . DOI: . 2010 /j.cub. 6417. .
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