Science

Great Barrier Reef sea turtles are 99 per cent female

Great Barrier Reef sea turtles are 99 per cent female”

LINDGRENA population of green turtles, whose sex is determined by in-nest temperatures, has become nearly 99 percent female in recent decades, according to a report in Current Biology on Monday (January 8).

If we don't actively combat climate change, we may lose green sea turtles forever.

The population of about 200,000 nesting females in the northern Great Barrier Reef could crash without more males, according to the report.

In one population towards the southern end of the reef, the turtles skewed 65-69% female, according to the researchers.While that's bad for that populatio' survival rate, it's not almost as alarming as what the researchers found in a genetically distinct population in the warmer areas toward the northern tip of the Great Barrier Reef. "We can't out-run increasing temperatures [forever]. without making a long-term effort to fix the things that are causing it".

An egg in hot sand is more likely to produce a female turtle, and an egg in cool sand is more likely to produce a male. At a "pivot" temperature (29.3 degrees Celsius), turtles hatch with a relatively even split between males and females, according to the researchers.

A total of 86.8 percent of adult-sized turtles from the area were female.

"With warming global temperatures and most sea turtle populations naturally producing offspring above the pivotal temperature, it is clear that climate change poses a serious threat to the persistence of these populations", the study's authors wrote. The genetic analysis allowed researchers to determine whether the turtle had been born in the northern or southern parts of the reef, which are separated by about 1,200 miles.

David Owens, a professor emeritus from the College of Charleston in SC, was not involved in the new study but said he has dreamed of doing such research for years.

This is extreme - like capital letters extreme, exclamation point extreme.

More news: Catherine Deneuve accuses #Metoo of having a hatred of men

Allen said the government of Australia has started to take steps toward helping sea turtles, such as funding the Raine Island Recovery Project to study and support the local turtle population. "We won't see the effects of what's happening today for several decades", she said. Common sense tells you: "One male and a hundred females ― that's going to be a very exhausted boy".

Wyneken agrees. "If nothing changes, then it's going to be a problem", she says. That's so weird, sea turtles.

The transformation has led scientists to be concerned about the species' future - with just 0.2 per cent of the turtles being male in some areas.

"Generally, this is very important work that needs to be replicated among other major rookeries", Mansfield, who works at the University of Central Florida's marine turtle research group, told HuffPost. "So there's been something happening over the past 20 years, and if it's not climate change, I'm not sure what it is".

"Although increased breeding frequency, as well as polygynous behavior of male turtles, may help mitigate skewing offspring sex ratio, it is unknown how many (or what minimum proportion of) males is sufficient to sustain sea turtle populations", writes the team. "We don't know how resilient sea turtle species are when faced with such rapid changes in climate, habitat availability, and developmental pressure".

The turtles play a crucial role in keeping their habitat healthy. Without the turtles' grazing, seabeds become unhealthy, which affect all other animals higher on the food chain.

In theory, "as areas become warmer. there are fewer males produced", Wyneken continues, "and that is what this paper is showing".

"But those are band-aids", says Wyneken. The reason, according to the study's authors, has everything to do with rising temperatures.



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