Green turtles appear to jump into the open sea shortly after hatching on the Florida coast and then disappear. Currently, new tracking data show that many sea turtles drop out of the current after surfing the Gulf Stream northward. The Sargasso Sea, an oasis of cozy seaweed and abundant food.
The new study was published in the journal on Tuesday (May 4th) Bulletin of the Royal Society B, Scientists have tagged 21 green turtles with solar-powered satellites (Green turtle) The age of the “infant”, that is, about 3-9 months after birth. The young turtle weighed just over 10.5 ounces (300 grams) and had a shell length of about 5-7 inches (12-18.6 centimeters). Tagging such small creatures poses a major challenge, both due to their early size and the fact that they grow and change shape fairly rapidly compared to mature animals.
Despite the hurdles, to better protect the ocean tortoise “We really need to tag some of these little guys,” said Kate Mansfield, director of the Sea Turtle Research Group and associate professor of biology at the University of Central Florida. Stated. The movement of young turtles into the open ocean is often referred to as the “lost year.” Scientists know very little about what animals do before returning to the beach as “teenagers.”
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“In general, sea turtles do not mature for at least 20 years, and they don’t know much about sea turtles in the years leading up to adulthood,” said Mansfield. Now, thanks to follow-up data, “the Sargasso Sea has emerged as an important habitat for sea turtles in the early stages of life,” she said.
Turtle toddler adventure
The Sargasso Sea, named after the floating brown genus Algae Called SargassumIs the only sea whose edges are defined by ocean currents, not land boundaries. According to the US National Oceanic and Atmospheric Administration (NOAA). The sea is in the so-called North Atlantic subtropical gyre. This is a large circle consisting of four major currents: the Gulf Stream in the west, the North Atlantic Current in the north, the Canary Current in the east, and the North Atlantic Equator Current. Flow to the south.
In past studies, researchers have found young green turtles and loggerhead turtles (Caretta Caretta), Passively drifting these streams, often SargassumSaid Mansfield. These observations, as well as sightings of Florida turtles in the East Atlantic, suggested that turtles could form large loops around the gyre before returning to the United States as juveniles.
However, Mansfield and her colleagues wanted to obtain solid evidence of this move, identifying how long the turtle would normally stay offshore. Research author Jeanette Wyneken, a professor of biological sciences at Florida Atlantic University, said, “Are they absent for a year or 10 years? These are pretty basic questions.”
Designed for adult turtles, satellite tags “looked like bricks” the size of a cell phone, Mansfield said. However, she said, with the advent of tags as small as the length of a finger, the team could start tracking young turtles. They started with loggerhead turtles and tagged 17 turtles in a 2014 study.Rather than passively drifting, they found that Loggerhead frequently exited the current and swam into warm, nutrient-rich waters, including the waters of the Sargasso Sea, they reported in the journal. did Bulletin of the Royal Society B..
The team thought that green turtles could be just as active swimmers when they reach the open sea, so Green turtle Child turtle.
The team collected freshly hatched turtles from Boca Raton on the southeastern coast of Florida and returned them to the laboratory for months of rearing. The team’s satellite tags are small, but still too big for a freshly hatched turtle, Mansfield said. The team initially tried to attach the tag using the same glue that was used for the loggerhead. This is a type of nail polish acrylic that eventually peels off as the animal grows.
“But that didn’t work for green turtles,” Mansfield said. The loggerhead turtle’s shell is not very smooth, while the texture of the young green turtle’s shell feels “wax-like” like human claws sprinkled with cuticle oil. Before the team finds glue that sticks to slippery turtles, glue used to cement tooth fillings, glue used to attach theater prostheses to the skin, and much more. I tried the adhesive.
It was, after all, a marine urethane adhesive usually used to seal boats. The glue is flexible enough to stretch as the turtle grows, but it pops out as soon as the turtle reaches a certain size.
After confirming that the glue was safe and sticky, the team released the turtles into the western Atlantic Ocean and followed them for an average of 66 days. They were able to track several turtles for over 100 days and one for 152 days. They found that their turtles, like Loggerhead, were mostly swimming near sea level and coasting along the Gulf Stream. However, in general, turtles shed from the Gulf Stream and the adjacent North Atlantic Current earlier than Loggerhead.
After that, about two-thirds of these green turtles went high-tailed towards the Sargasso Sea and stayed there until no tags were sent. This suggests that Sargasso functions as an attractive nursery for turtles.
“That habitat, it makes sense,” Mansfield said. Seaweed provides camouflage to small turtles while slowing the flow of water and allowing the sun to heat its surface. Sea turtles are cold-blooded and require warm water to survive, and if they get too cold they will grow significantly slower. Other larval marine animals such as shrimp, crabs and fish Sargassum Feed the growing turtles.
But while some young sea turtles flock to Sargassum, the question remains as to why some swim towards the ocean and why other turtles remain in the ocean, Mansfield said.It’s amount Sargassum According to a 2011 survey, its distribution along the eastern United States varies from season to season. International Journal of Remote Sensing..
So while some turtles encounter Sargassum Follow the Gulf Stream towards the Sargasso Sea. “Some people may have missed it. Sargassum I’m on a boat and hanging out in the stream. “
And when the turtle reaches the Sargasso Sea, another question arises.
“I think those animals will probably be there for a couple of years,” Winken said, but she added that it was a “pure guess.” “If you’re in a safe place, why leave it?” Mansfield said, reflecting Winken’s feelings. Green turtles usually return to Florida as juveniles, stay in coastal habitats until they become adults, and feed on algae, seagrass, and jellyfish. The Sargasso Sea will probably meet many of the needs of turtle toddlers until they reach that important turning point.
But scientists will need more follow-up data to know exactly how long they will stay in seaweed-containing habitats, Mansfield said. She said they could track turtles on their way to Sargasso, so the team could potentially look for turtles that already lived there and tag them in the field. Regardless of how long the turtle stays, the Sargasso appears to be an important habitat for young animals. In the future, she said, in order for turtles to grow and lay their own eggs, they need to protect the ocean.
“The Sargasso Sea cannot be another dump. It must be recognized as an important habitat for endangered species,” Wyneken said. “It’s probably not just about green turtles,” she added, given that other young marine animals also grow in seaweed.
Originally published in Live Science.
A young green turtle chased to a hideout in the “lost year”
Source link A young green turtle chased to a hideout in the “lost year”