Microplastics have been found deep in the sand on beaches where sea turtles lay their eggs. Such pollution could eventually affect turtle breeding and even the ratio of male to female hatchlings.
An average of 5,300 particles of microplastic per cubic metre were identified at depths of 60 centimetres on beaches in Cyprus used by green turtles and loggerheads.
At the surface, up to 130,000 fragments of plastic were found – the second-worst level ever recorded on a beach after Guangdong in South China.
If conditions worsen, such pollution could eventually begin to affect hatching success and even the ratio of male and female turtle hatchlings, warned the researchers from the University of Exeter in a statement.
“We sampled 17 nesting sites for loggerhead and green turtles and found microplastics at all beaches and all depths,” commented Emily Duncan from the university. “Microplastics have different physical properties to natural sediments, so high levels could change the conditions at hatching sites, with possible effects on turtle breeding.”
As an example, she cited the temperature at which the egg incubates. This affects the sex of the hatchling, with females more likely in warmer conditions.
Microplastics, which are defined as being less than 5mm in diameter, come from numerous sources including discarded plastic items that have broken apart, microbeads from cosmetics and microfibres from clothes.
Of the microplastics categorised in this research, nurdles (pellets used in the production of plastic products) and hard fragments broken from larger items were the most common. Unlike the beaches in China where the highest levels of microplastics have been recorded, the Cyprus beaches are located far from industrial practices.
“It seems that microplastics are arriving on ocean currents. In this case, our analysis suggests most of it came from the eastern Mediterranean basin. This is also true of the large plastic items found on the beaches in Cyprus in large numbers,” said Professor Brendan Godley of the university.
The findings support the theory that beaches act as a “sink” for marine microplastics, becoming key areas for contamination, according to the statement.
Photo credit: Tim Sheerman-Chase/ CC BY 2.0