From EurekAlert!
Public Release: 19-Dec-2018
Warming warning over turtle feminization
University of Exeter
Up to 93% of green turtle hatchlings could be female by 2100, as climate change causes “feminisation” of the species, new research suggests.
The sex of turtle hatchlings is determined by temperature, and at present about 52% of hatching green turtles – one of seven species of sea turtle – are female.
But a study by the University of Exeter and the Marine and Environmental Sciences Centre (Portugal) shows that in warmer temperatures predicted by Intergovernmental Panel on Climate Change (IPCC) scenarios, 76-93% of hatchlings would be female.
The figures are specific to the study site in Guinea-Bissau, West Africa, but researchers say they expect a similar picture globally.
They say the changing gender ratio would initially lead to more females nesting, increasing the population, before by a decline “as incubation temperatures approach lethal levels”.
They also predict rising sea levels will submerge 33-43% of current nesting areas used by green turtles on the beaches where the study was carried out.
“Green turtles are facing trouble in the future due to loss of habitats and increasing temperatures,” said Dr Rita Patricio, of the Centre for Ecology and Conservation on the University of Exeter’s Penryn Campus in Cornwall.
“Our results suggest the nesting population of green turtles the Bijagós Archipelago, Guinea-Bissau, will cope with the effects of climate change until 2100.
“Cooler temperatures, both at the end of the nesting season and in shaded areas, will guarantee some hatchlings are male.
“Although rising temperatures will lead to more female hatchlings – and 32-64% more nesting females by 2120 – mortality in eggs will also be higher in these warmer conditions.
“As temperatures continue to rise, it may become impossible for unhatched turtles to survive.”
The research team, which included the Institute of Biodiversity and Protected Areas of Guinea-Bissau, say nesting sites submerged by rising seas may not simply “move” inland.
“Beach retreat may be OK in some areas, but the turtles we studied were nesting on a small island (Poilão Island) so there is a limit to how far the beach can go,” Dr Patricio said.
“In other places there may be natural barriers or human constructions that stop beaches moving inland.”
The Bijagós Archipelago is the most important nesting place for green turtles in Africa, and the main breeding ground for the species in the South Atlantic.
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The research was funded by the MAVA Foundation.
The paper, published in the journal Global Change Biology, is entitled: “Climate change resilience of a globally important sea turtle nesting population.”
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It really is amazing how much change an increase of only a few tenths of a degree is supposed to cause.
Of course the whole thing is based on an assumption that the oceans will continue to warm. Best I can tell the opposite is starting to occur.
Alarum-types keep recirculating old impact stuff every ten years. I think I have detected a cycle or recycle period in climate. Dare I call it the Pearse cycle? One could say they have confused the turtle with a chestnut.
Brother, write up a pretty, double talky paper and get that grant money! Then we are off to Haiti.
Sea turtles have been around for >100 million years. Through hotter and colder (ice age) times. Somehow these itty-bitty temperature changes do not worry me (or the turtles).
https://oceantoday.noaa.gov/endoceanseaturtles/
If these “researchers” had just discovered that “The sex of turtle hatchlings is determined by temperature”, and this was a change in their life cycle that had only recently developed, within that past 1000 years or so, they might have something of importance to write about. There might be some valid concern about warming seas and/or rising sea levels. However, since sea turtles have apparently been reproducing the same way for around 100 Million years, while entire continents have risen and submerged and the oceans have warmed and cooled far more than what might happen by 2100, this is all complete bull5h1t (and a complete waste of my time on Christmas Day).
Merry Christmas to all.
It is turtles all the way down…
https://www.theguardian.com/environment/2018/dec/26/climate-change-sea-turtles-massachusetts
They say the changing gender ratio would initially lead to more females nesting, increasing the population, before by a decline “as incubation temperatures approach lethal levels”.
They also predict rising sea levels –>
and turtles being that dumb after 100 of millions of years evolution not to know where to nest and return to however risen sea level strands.
It could also be a consequence of Wolbachia infecting colonies. The next big story will be the whales cubs are missing.
With a perfect bogeyman (climate) who needs real reasons?!?
I call massive bullshit.
I’ve once checked on this and found many news articles that were about other male species turning into females.
IMO, what is happening is that we are somehow putting chemicals in the environment that is causing these species to feminize.
Think this is also affecting us because my doctor told me that men’s T levels in thie later years used to be much higher several decades ago.
So there are more female turtles and therefore more turtles hatched if the weather is warmer.
Sounds like a positive response to warmer climes.
The female population in all species increasing than male. This change disturbing the natural proportion of the population it is at high risk in Future.