Climate change is a serious issue that results in visible environmental problems including arctic ice loss, rising sea levels, changes in vegetation patterns, and habitat loss. However, recent surging extremities in global temperatures have caused a never-seen-before effect on our ecosystem that the public didn’t expect—an overwhelming majority of green turtles are being born female, and their numbers are only increasing.
The primary cause of this phenomenon can be attributed to the basic genetic composition of the species. Green sea turtles exhibit temperature-dependent sex determination, largely due to the synthesis of an enzyme called aromatase. This protein aids the conversion of sex steroids from male sex hormones to female sex hormones during development. During the thermosensitive period, variations of temperature increase the activity of aromatase, further stimulating the development of the turtles into females. With rising atmospheric and sea temperatures, a greater number of females than males was expected, but not to the extent of what was discovered.
A study by the National Oceanic and Atmospheric Administration that California State University and Worldwide Fund for Nature Australia published on January 8, 2018 observed sex ratios of the largest sea turtle populations in the world. Findings showed that more than 99 percent of the turtles hatched in the northern Great Barrier Reef were female, with 1 male for at least every 116 females. Although sea turtle populations are fully capable of surviving with fewer males than females, the severe results and discussion of the study suggest that the complete feminisation of this population is very possible in the near future.
Changes in hatching locations in the near future are unlikely as the turtles’ instinct is to nest in the same spot at which they were born. Extreme temperatures are leading to catastrophic rises in incubation temperatures that are also posing a great threat to the survival of the population. The disappearance of this population of turtles, like the extinction of any species, has environmental consequences as well; any disruption of the food web creates the risk of a domino-like effect within its ecosystem. Habitats with less biodiversity are at the highest risk for mass extinction as any loss could be devastating. Although coral reefs are diversely populated, the loss of a single species could still have extreme adverse effects. The disappearance and unusual sex ratio of the green turtle shows the importance of active concern for the environment, and appreciation and support for individuals working toward a collectively healthier planet.