Ingesting just one piece of plastic can prove deadly for sea turtles, according to new research published in the journal Scientific Reports.

Examining postmortem reports and animal stranding reports concerning sea turtles in Queensland, the team discovered the following:

• Sea turtles had a one in five chance of death after consuming just one plastic item, which jumps to a 50% chance for turtles consuming 14 pieces.
• If an animal consumed more than 200 pieces of plastic, death was a certainty.
• Juvenile turtles are at greater risk of plastic-related deaths.
• Researchers estimate that half of the world’s population of sea turtles have ingested plastic.

Lead author Dr. Britta Denise Hardesty from Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) explained that the sea turtles are vulnerable "because of their digestive tract; they don't regurgitate anything.

"If it ends up in the wrong place, even one little thin, filmy piece of plastic can block that canal and mean that nothing can pass and ultimately the blockage can result in death."

Juvenile turtles are even more vulnerable than older turtles with researchers estimating that they consume more plastic than their adult counterparts.

"Young small turtles actually drift and float with the ocean currents as does much of the buoyant, small lightweight plastic," said Dr. Hardesty.

"We think that small turtles are less selective in what they eat than large adults who eat sea grass and crustaceans, the young turtles are out in the oceanic area offshore and the older animals are feeding in closer to shore."

While sea turtles live until roughly 80 years old, reproducing decade after decade, the research team is concerned about the long-term impact of plastic consumption on the juvenile turtles.

"We know that disproportionately finding it more in younger animals who won't make it to the reproductive state will have long-term consequences for the survival of the species," said Dr. Hardesty.

"It's very concerning."

Calling the research important for attempting to quantify the scale of the threat posed by plastic, experts in the field have joined in the conversation.

"The authors offer a very defensible framework for allowing us to measure the mortality risk resultant from plastic ingestion," said Professor Brendan Godley, from the University of Exeter, who wasn't involved with the study.

"It also points to the likelihood that plastic may be a key threat to the smallest life stages. This is of particular concern as pieces of plastics and baby turtles are both likely to be aggregated together in similar areas."

To try to find a solution, Dr. Hardesty recommends rethinking our relationship with plastic.

"Let's put a true cost on plastic so they have a similar value to aluminum cans which we don't find lost in the environment, they get picked up and they don't get mismanaged and find their way out into the ocean."