Science

Rising temperatures turning green sea turtles female in Great Barrier Reef

Rising temperatures turning green sea turtles female in Great Barrier Reef

With such a profound lack of males for around 200,000 nesting females to reproduce with, the population of the creatures off Australia's Queensland coast could crash, a study has found.

"With average global temperature predicted to increase 2.6 degrees Celsius by 2100, many sea turtle populations are in danger of high egg mortality and female-only offspring production", said the report.

Climate change is being blamed, since the sex of a sea turtle is determined by the heat of the sand where they lay their eggs.

Biologists consider 84.74 degrees Fahrenheit to be the pivotal temperature for green sea turtles to be born a mixture of female and males. A few up or down into the temperature can affect the natural balance of this species.

"This is extreme-like capital letters extreme, exclamation point extreme", Camryn Allen, a National Oceanic and Atmospheric Administration (NOAA) endocrinology researcher and the study's co-author, told National Geographic. The research includes the study of two genetically different population of turtles on the reef.




This unique biological trait of these creatures is what that has jeopardised their future in an increasingly warmer world as rising temperatures due to climate change are turning one of the world's largest sea turtle colonies nearly entirely female, a new study revealed. The scientists discovered that the group of turtles located in the cooler southern area of the reef were between 65% and 69% female, while the group from the northern area of the reef had a much higher percentage of females. Those turtles are already considered endangered species.

So, the researchers developed a new technique: Studying the turtles' hormones.Proving that the increasing temperatures actually changed the turtle population proved challenging, though. He informed that the current situation is really alarming.

"Knowing what the sex ratios in the adult breeding population are today and what they might look like five, 10 and 20 years from now when these young turtles grow up and become adults is going to be incredibly valuable".

"It is clear that climate change poses a serious threat to the persistence of these populations". It affects the temperature-dependent sex determination (TSD). Dermot O'Gorman, the Chief Executive of WWF Australia, stated that first the coral bleaching and now the rising temperature has severely affected the marine animals. On the other hand, the scientists are taking important steps like trialing the use of shade cloth in nesting beaches which will lower the sand temperature, and trying to reduce bycatch in the fishing industry, stated O'Gorman.