A new study, published on February 19, 2025, in The Royal Society, reveals that rising sea temperatures are driving green turtles to nest earlier in the season—an adaptation that could help them cope with climate change.
Scientists analyzed 31 years of nesting data from over 600 individually marked female green turtles (Chelonia mydas) at Alagadi Beach, North Cyprus. They found that for every 1°C increase in sea surface temperature, females advanced their nesting by approximately 6.47 days. This shift, the researchers concluded, is largely due to individual plasticity—an organism’s ability to adjust its behavior or physiology in response to environmental changes.
A Race Against Rising Temperatures
Phenological changes—shifts in the timing of biological events—are common responses to climate change. However, distinguishing between individual-level flexibility and population-wide evolutionary adaptation remains a challenge. This study found that roughly 30% of the turtles’ nesting shifts were due to individual plasticity, meaning the same turtles returned to nest earlier as temperatures increased. The remainder of the shift was driven by factors such as the age and size of nesting females, as well as their breeding experience and number of clutches laid per season.
Sea turtles, like other ectotherms (cold-blooded animals), are highly sensitive to temperature changes. Nesting too late in the season could expose eggs to excessively warm conditions, reducing hatchling survival and skewing sex ratios toward more females, since temperature influences turtle embryo development.
Will This Adaptation Be Enough?
While this flexibility offers a glimmer of hope for green turtles, the researchers caution that it’s unclear whether these changes will be sufficient to counteract the full impact of climate change. The study highlights that turtles at this site have been able to advance their nesting to maintain favorable conditions, but for species with highly specific thermal requirements, adaptation may not always keep pace with climate shifts.
Understanding how migratory marine species respond to changing environments is crucial for conservation efforts. As climate change continues to reshape ecosystems, studies like this help predict which species may successfully adapt—and which may require greater human intervention to ensure their survival.
Research Study Source
Rickwood, M.L., Tucker, E., Beton, D., Davey, S., Godley, B.J., Snape, R.T.E., Postma, E., & Broderick, A.C. (February 19, 2025). Individual plasticity in response to rising sea temperatures contributes to an advancement in green turtle nesting phenology. Proceedings of the Royal Society B, 2024(1809). https://doi.org/10.1098/rspb.2024.1809
