New ocean model highlights rare look into sea turtles' 'lost years'
By
Adriana Navarro, AccuWeather staff writer
Updated Mar 10, 2021 8:30 PM EDT
Members of the Sea Turtle Rescue Alliance will use telemedicine and cloud-based technology to assist different sea turtle rehabilitation centers around the world.
The hatching of baby turtles has always been a celebration of new life for the endangered species with each hatchling able to escape the hungrily awaiting predators and make it to the sea a small victory. While beachgoers, environmentalists and tourists have all participated in guiding as many of the hatchlings as they can in their mad dash to the sea, little is known about what happens to them during their first few years of life, or what scientists have called their "lost years."
Now, a detailed global ocean model simulation from the National Center for Atmospheric Research (NCAR) has given scientists some insight into where the hatchlings go once escaping into the ocean, which been a mystery until now.
FILE - In this June 30, 2019, file photo provided by the Georgia Department of Natural Resources, a loggerhead sea turtle returns to the ocean after nesting on Ossabaw Island, Ga. Louisiana will help inshore shrimpers buy turtle escape hatches that will be required next year for some boats, Gov. John Bel Edwards said Tuesday, Oct. 13, 2020. The program affects only Louisiana shrimpers requiring turtle excluder devices in some skimmer trawls to take effect in all Gulf and southeastern Atlantic states on April 1, 2021. (Georgia Department of Natural Resources via AP)
The model looks at key locations extending from hatching grounds of the endangered loggerhead turtles to the open sea, and scientists are hopeful it will allow them to expand their efforts in protecting the species outside of just the nesting grounds.
The simulation was used in a study published on Feb. 24, 2021, as "Identifying global favourable habitat for early juvenile loggerhead sea turtles" in the journal Royal Society Interface, led by Cheryl Harrison, a researcher at the University of Texas Rio Grand Valley.
"Sea turtle hatchlings are very difficult to track and observe as they have high mortality rates and grow out of tags quickly," Harrison said, according to a press release from NCAR. "Modeling studies help us close this observational gap and predict where they are going in the 'lost years.' Identifying ocean habitat helps us understand what factors are important for their survival in this life stage."
An animation showing how baby sea turtles likely disperse from a nesting site in Japan into the open ocean. The "turtles" are the green particles in this simulation, which was run using a high-resolution version of the NCAR-based Community Earth System Model. (National Center for Atmospheric Research/Cheryl Harrison)
Focusing on the loggerhead sea turtles, the study simulated at the dispersal of hatchlings over their first year of life after departing from eight major nesting sites across the globe -- one from Japan, Florida, Cape Verde, Oman, west Australia, east Australia, Brazil and South Africa -- in four representative years using a method known as particle tracking. This method follows how particles "released" into the model move with simulated water trajectories, according to the news release.
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"We find that, globally, rookeries are positioned to disperse to regions where the lower trophic biomass is greatest within loggerheads' thermal range," the study said.
Out of the eight nesting sites they used in the simulation, six of them were associated were near strong currents, such as the Gulf Stream, which then sweep the turtles toward the poles to a region of the ocean where two circular ocean currents, or gyres, meet. In the boundary between the subpolar and subtropical gyres, the study says it's warm enough for the baby sea turtles to survive and feed off zooplankton.
During the "lost years" of the sea turtles who hatched from the beaches of southeast Florida, the turtles caught a ride via Gulf Stream to the Azores where they flourish.
A baby loggerhead turtle (Caretta caretta) struggles to reach the Mediterranean Sea, in Adrasan, Antalya, Turkey, early Sunday, Aug. 11, 2019. Caretta carettas, a rare species facing the threat of extinction, lay their eggs on certain beaches only and their breeding season is between May 1 to October 1. (AP Photo/Burhan Ozbilici)
(AP Photo/Burhan Ozbilici)
Alternatively, hatchlings from the coast of Japan were transported to the central North Pacific, where the closest coastal foraging habitat was miles away in all directions.
"These differences in habitat at the end of the first year likely contribute to the ultimate success of hatchlings from the U.S. East Coast in general, and the large number of nests there relative to other boundary current sites," the study pointed out, noting as well the heightened energetic costs to return to nesting sites are likely much higher in the North Pacific.
At the other two nesting sites, such as the one at the coast of Oman, a country on the southeastern coast of the Arabian Peninsula, the sea turtles didn't venture too far from "home" as the local waters were already suitable.
In this July 5, 2019, photo provided by the Georgia Department of Natural Resources, a loggerhead sea turtle returns to the ocean after nesting on Ossabaw Island, Ga. The giant, federally protected turtles are having an egg-laying boom on beaches in Georgia, South Carolina and North Carolina, where scientists have counted record numbers of nests this summer. (Georgia Department of Natural Resources via AP)
Up until this point, the technology typically used to determine where the sea turtles may have gone, and even what routes would have had the most food available to them, was not detailed enough for them to track the turtles.
"To understand where sea turtle hatchlings are being swept to when they enter the open ocean -- and how favorable that habitat is to turtle survival -- we need to simulate smaller scale ocean features, the jets an eddies that transport these younglings," Harrison said. "The models typically used to simulate global ocean movement are too coarse for us to resolve these important features. The really exciting thing about this study is we were able to use a high-resolution, eddy-resolving model to track where turtles are traveling."
The ocean simulation used was run using the NCAR-based Community Earth System Model at a resolution that is an order of magnitude higher than standard global modeling runs, according the press release. In addition, the model contains complex biogeochemistry, allowing researchers to estimate food availability on the turtles' odyssey.
Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, Fubo, and Verizon Fios.
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News / Weather News
New ocean model highlights rare look into sea turtles' 'lost years'
By Adriana Navarro, AccuWeather staff writer
Updated Mar 10, 2021 8:30 PM EDT
Members of the Sea Turtle Rescue Alliance will use telemedicine and cloud-based technology to assist different sea turtle rehabilitation centers around the world.
The hatching of baby turtles has always been a celebration of new life for the endangered species with each hatchling able to escape the hungrily awaiting predators and make it to the sea a small victory. While beachgoers, environmentalists and tourists have all participated in guiding as many of the hatchlings as they can in their mad dash to the sea, little is known about what happens to them during their first few years of life, or what scientists have called their "lost years."
Now, a detailed global ocean model simulation from the National Center for Atmospheric Research (NCAR) has given scientists some insight into where the hatchlings go once escaping into the ocean, which been a mystery until now.
FILE - In this June 30, 2019, file photo provided by the Georgia Department of Natural Resources, a loggerhead sea turtle returns to the ocean after nesting on Ossabaw Island, Ga. Louisiana will help inshore shrimpers buy turtle escape hatches that will be required next year for some boats, Gov. John Bel Edwards said Tuesday, Oct. 13, 2020. The program affects only Louisiana shrimpers requiring turtle excluder devices in some skimmer trawls to take effect in all Gulf and southeastern Atlantic states on April 1, 2021. (Georgia Department of Natural Resources via AP)
The model looks at key locations extending from hatching grounds of the endangered loggerhead turtles to the open sea, and scientists are hopeful it will allow them to expand their efforts in protecting the species outside of just the nesting grounds.
The simulation was used in a study published on Feb. 24, 2021, as "Identifying global favourable habitat for early juvenile loggerhead sea turtles" in the journal Royal Society Interface, led by Cheryl Harrison, a researcher at the University of Texas Rio Grand Valley.
"Sea turtle hatchlings are very difficult to track and observe as they have high mortality rates and grow out of tags quickly," Harrison said, according to a press release from NCAR. "Modeling studies help us close this observational gap and predict where they are going in the 'lost years.' Identifying ocean habitat helps us understand what factors are important for their survival in this life stage."
An animation showing how baby sea turtles likely disperse from a nesting site in Japan into the open ocean. The "turtles" are the green particles in this simulation, which was run using a high-resolution version of the NCAR-based Community Earth System Model. (National Center for Atmospheric Research/Cheryl Harrison)
Focusing on the loggerhead sea turtles, the study simulated at the dispersal of hatchlings over their first year of life after departing from eight major nesting sites across the globe -- one from Japan, Florida, Cape Verde, Oman, west Australia, east Australia, Brazil and South Africa -- in four representative years using a method known as particle tracking. This method follows how particles "released" into the model move with simulated water trajectories, according to the news release.
CLICK HERE FOR THE FREE ACCUWEATHER APP
"We find that, globally, rookeries are positioned to disperse to regions where the lower trophic biomass is greatest within loggerheads' thermal range," the study said.
Out of the eight nesting sites they used in the simulation, six of them were associated were near strong currents, such as the Gulf Stream, which then sweep the turtles toward the poles to a region of the ocean where two circular ocean currents, or gyres, meet. In the boundary between the subpolar and subtropical gyres, the study says it's warm enough for the baby sea turtles to survive and feed off zooplankton.
During the "lost years" of the sea turtles who hatched from the beaches of southeast Florida, the turtles caught a ride via Gulf Stream to the Azores where they flourish.
A baby loggerhead turtle (Caretta caretta) struggles to reach the Mediterranean Sea, in Adrasan, Antalya, Turkey, early Sunday, Aug. 11, 2019. Caretta carettas, a rare species facing the threat of extinction, lay their eggs on certain beaches only and their breeding season is between May 1 to October 1. (AP Photo/Burhan Ozbilici)
Alternatively, hatchlings from the coast of Japan were transported to the central North Pacific, where the closest coastal foraging habitat was miles away in all directions.
"These differences in habitat at the end of the first year likely contribute to the ultimate success of hatchlings from the U.S. East Coast in general, and the large number of nests there relative to other boundary current sites," the study pointed out, noting as well the heightened energetic costs to return to nesting sites are likely much higher in the North Pacific.
At the other two nesting sites, such as the one at the coast of Oman, a country on the southeastern coast of the Arabian Peninsula, the sea turtles didn't venture too far from "home" as the local waters were already suitable.
In this July 5, 2019, photo provided by the Georgia Department of Natural Resources, a loggerhead sea turtle returns to the ocean after nesting on Ossabaw Island, Ga. The giant, federally protected turtles are having an egg-laying boom on beaches in Georgia, South Carolina and North Carolina, where scientists have counted record numbers of nests this summer. (Georgia Department of Natural Resources via AP)
Up until this point, the technology typically used to determine where the sea turtles may have gone, and even what routes would have had the most food available to them, was not detailed enough for them to track the turtles.
"To understand where sea turtle hatchlings are being swept to when they enter the open ocean -- and how favorable that habitat is to turtle survival -- we need to simulate smaller scale ocean features, the jets an eddies that transport these younglings," Harrison said. "The models typically used to simulate global ocean movement are too coarse for us to resolve these important features. The really exciting thing about this study is we were able to use a high-resolution, eddy-resolving model to track where turtles are traveling."
The ocean simulation used was run using the NCAR-based Community Earth System Model at a resolution that is an order of magnitude higher than standard global modeling runs, according the press release. In addition, the model contains complex biogeochemistry, allowing researchers to estimate food availability on the turtles' odyssey.
Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, Fubo, and Verizon Fios.
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