Warming temperatures could result in extinction of sea turtles

London : Climate change may negatively impact the sea turtle population, as warmer temperatures could lead to higher numbers of females and increased nest failure, scientists have warned.

The temperature at which sea turtle embryos incubate determines the sex of an individual, which is known as Temperature-Dependent Sex Determination (TSD). The pivotal temperature for TSD is 29 degrees Celsius as both males and females are produced in equal proportions - above 29 degrees Celsius mainly females are produced while below 29 degrees Celsius more males are born.

"Up to a certain point, warmer incubation temperatures benefit sea turtles because they increase the natural growth rate of the population: more females are produced because of TSD, which leads to more eggs being laid on the beaches," said Jacques-Olivier Laloe from Swansea University in the UK.

However, beyond a critical temperature, the natural growth rate of the population decreases because of an increase of temperature-linked in-nest mortality, researchers said. "Temperatures are too high and the developing embryos do not survive. This threatens the long-term survival of this sea turtle population," Laloe said.

Sea turtle eggs only develop successfully in a relatively narrow thermal range of about 25-35 degrees Celsius, so if incubation temperatures are too low the embryo does not develop but if they are too high then development fails, they said. This means that if incubation temperatures increase in the future as part of climate warming, then more sea turtle nests will fail.