The plastic present in the oceans, ingested more and more often by sea turtles, is creating an evolutionary trap
The plastic present in the oceans, ingested more and more often by sea turtles, is giving rise to an evolutionary trap that jeopardizes the survival of several species. This is revealed by a disturbing new scientific research.
Plastic pollution is more dangerous than imagined, especially for animals that live in the oceans. Among the most threatened by far are sea turtles, especially the youngest ones. For them, plastic is giving life to what scientists have called an "evolutionary trap", on which new scientific research just published in the journal Frontiers in Marine Science has focused.
The study was led by researchers from the University of Exeter who found a surprising number of microplastics in the stomachs of small turtles living along the east and west coasts of Australia. In this area shortly after hatching, sea turtles venture out into the open sea, but currents carry large amounts of plastic that these creatures often tend to ingest.
Juvenile turtles have evolved to live in the open sea, where predators are relatively scarce - explains Dr Emily Duncan of the Center for Ecology and Conservation of Cornwall's Penryn Campus in Exeter. - However, our results suggest that this evolved behavior now leads them into a 'trap', leading them to highly polluted areas such as the Great Pacific Garbage Patch. Juvenile sea turtles generally don't have a specialized diet - they eat just about anything, and our study suggests this includes plastic.
The great threat of microplastics (ingested more and more often by sea turtles)
The research focused on 121 specimens of sea turtles, beached or accidentally caught by fishermen, belonging to five species: green, Loggerhead, Hawksbill, Olive Ridley and flat-backed.
Scientists found more traces of plastic in turtles living on the Pacific coast: 86% of the fragments were found in the Caretta Caretta species, 83% in the green turtles, 80% in the flat-backed ones and in 29 % in Olive Ridley specimens. On the other hand, the percentages of plastic found in turtles living on the Indian Ocean coast are much lower: 28% of the fragments were found in flat-backed turtles, 21% in Caretta Caretta and 9% in those. greens.
As the study reveals, turtles tend to actually ingest everything. In the gastrointestinal tract of sea turtles, scholars have in fact found pieces of plastic belonging to the most disparate objects: plastic bags, pieces of ropes, polystyrene, rubber, rubber bands, fishing nets. The polymers most commonly ingested by turtles are polyethylene and polypropylene.
These polymers are so widely used in plastic products that it is impossible to pinpoint the sources of the fragments we have found - comments Dr. Duncan. - The pups generally contained fragments up to about 5 mm to 10 mm in length.
Read also: The plastic waste on the beaches is giving birth to all female turtles, the alarm of the biologists
The impact of plastic pollution on turtle survival
This situation has alarmed scientists, worried about the survival of sea turtles.
"It has been shown that the ingestion of plastic can create changes in relation to the acquisition of nutrients and the consequences on physical fitness in sea turtles of being associated with disease or mortality," the study reads.
However, it is still unclear what the actual impacts of plastic pollution are on these species, which could be even more devastating than expected. And to find out, more studies will be needed.
Investigating these concepts will be critical as evolutionary traps are rarely recognized by wildlife conservation professionals as a significant conservation threat that should be integrated into conservation planning and management - explains the team of scientists who conducted the study. - This will require close collaboration with researchers and veterinarians from around the world.
One thing is certain: we human beings are the architects of the evolutionary trap ...
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Fonte: Frontiers in Marine Science
Read all our articles on sea turtles:
- The sanctuary that saves thousands of endangered turtles, hit by boats and plastic
- The plastic waste on the beaches is giving birth to all female turtles, the alarm of the biologists
- Japan is among the countries most involved in the illegal trafficking of sea turtles: their beautiful shells used to make ornaments
