The study by Dr Jacques-Olivier Laloë of the University’s College of Science and published in the Global Change Biology journal, argues that warmer temperatures associated with climate change could lead to higher numbers of female sea turtles and increased nest failure, and could impact negatively on the turtle population in some areas of the world.
The effects of rising temperatures
Rising temperatures were first identified as a concern for sea turtle populations in the early 1980s as the temperature at which sea turtle embryos incubate determines the sex of an individual, which is known as Temperature-Dependent Sex Determination (TSD).
The study by Dr Jacques-Olivier Laloë of the University’s College of Science and published in the Global Change Biology journal, argues that warmer temperatures associated with climate change could lead to higher numbers of female sea turtles and increased nest failure, and could impact negatively on the turtle population in some areas of the world.
The effects of rising temperatures
Rising temperatures were first identified as a concern for sea turtle populations in the early 1980s as 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°C as both males and females are produced in equal proportions - above 29°C mainly females are produced while below 29°C more males are born. Within the context of climate change and warming temperatures, this means that, all else being equal, sea turtle populations are expected to be more female-biased in the future. While it is known that males can mate with more than one female during the breeding season, if there are too few males in the population this could threaten population viability.
The new study also explored another important effect of rising temperatures: in-nest survival rates. Sea turtle eggs only develop successfully in a relatively narrow thermal range of approximately 25-35°C, so if incubation temperatures are too low the embryo does not develop but if they are too high then development fails. This means that if incubation temperatures increase in the future as part of climate warming, then more sea turtle nests will fail.
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Picture courtesy of Kostas Papafitsoros
