Environment

Florida sea turtles face a new threat from microplastics: hotter sand

A new study of Florida beaches has found high amounts of microplastics, which could increase sand temperature and produce more female hatchlings. This Kemps ridley sea turtle makes its way to the Gulf of Mexico from the Texas coast.
A new study of Florida beaches has found high amounts of microplastics, which could increase sand temperature and produce more female hatchlings. This Kemps ridley sea turtle makes its way to the Gulf of Mexico from the Texas coast. Corpus Christi Caller-Times

With nesting season opening this week, Florida's sea turtles may face yet another threat from the plastic pollution choking the world's oceans.

According to a new study from Florida State University researchers, tiny, sesame seed-sized microplastics in sand could be heating up beaches and changing the balance of male and female sea turtles. Researchers sampling sand at loggerhead nesting sites along the Gulf Coast found the beads at every location they tested, with the concentration higher in dunes where turtles nest.

Plastic can absorb and retain more heat, leading researchers to worry that the beads could crank up sand temperature, which determines turtle sex as eggs incubate.

"Changes in incubation temperatures might modify the sex," Mariana Fuentes, coauthor of the study published Monday in the journal Marine Pollution Bulletin, said in a statement. "But at this stage we don't know how much microplastic is needed to see those changes."

sea turtle researcher.JPG
Florida State University researcher Victoria Beckwith samples sand at key locations on Gulf Coast beaches where loggerhead turtles nest for signs of microplastics. Courtesy of Victoria Beckwith

Plastic pollution across the planet has increasingly threatened wildlife, with the buoyancy and durability of microplastics posing a particular threat to marine animals. Just this month researchers announced new record levels found in Arctic ice.

While birds, whales, seals and other marine life can get tangled in plastic packaging and nylon ropes, microplastics can be easily ingested, posing a less obvious but still dangerous threat. A study of more than a thousand North Carolina sea birds found more than half had plastic in their guts. Scientists worry that microplastics may be settling onto the sea floor, and fear more impacts are going undetected across the vast oceans.

For their study, FSU researchers headed to the 10 most productive loggerhead nesting sites on beaches along the Panhandle's Gulf Coast. They found microplastic in every sample they collected, with higher amounts in sand from dunes.

baby loggerhead.jpg
A survey of loggerhead nesting sites on Florida's Gulf Coast has found elevated levels of microplastics in sand. This baby loggerhead was photographed on a South Carolina beach. Charles Slate Myrtle Beach Sun-New

Turtle researchers have already determined that rising temperatures are starting to influence hatchlings. Earlier this year, researchers confirmed that increasing temperatures near the Great Barrier Reef had led to a dramatic change in green sea turtle hatchlings, with 99 percent on one beach born female. Florida Atlantic University researchers looking at Boca Raton nests since 2002 also have reported females dominating hatchlings.

Keeping beaches dark at night and free of obstacles will help sea turtles during their nesting season, which began in Florida on March 1 and lasts through the end of October. Bright artificial lighting can misdirect and disturb nesting sea turtles

The FSU team plans to follow up on their findings by investigating just how much plastic may be increasing temperatures.

"The first step was to see whether sea turtles are exposed to microplastics," Fuentes said. "Next we'll explore its potential impacts."

Follow Jenny Staletovich on Twitter @jenstaletovich.

gulf coast nurtle nest map.PNG
Florida State University researchers examined sand at 10 loggerhead turtle nesting sites on barrier island beaches off the Panhandle and found microplastics in all the samples. Google Maps

  Comments