Nav: Home

Warming temperatures threaten sea turtles

June 21, 2017

The study by Dr Jacques-Olivier Laloë of the University's College of Science and published in the Global Change Biology journal, argues that warmer temperatures associated with climate change could lead to higher numbers of female sea turtles and increased nest failure, and could impact negatively on the turtle population in some areas of the world.

The effects of rising temperatures

Rising temperatures were first identified as a concern for sea turtle populations in the early 1980s as the temperature at which sea turtle embryos incubate determines the sex of an individual, which is known as Temperature-Dependent Sex Determination (TSD).

The pivotal temperature for TSD is 29°C as both males and females are produced in equal proportions - above 29°C mainly females are produced while below 29°C more males are born. Within the context of climate change and warming temperatures, this means that, all else being equal, sea turtle populations are expected to be more female-biased in the future. While it is known that males can mate with more than one female during the breeding season, if there are too few males in the population this could threaten population viability.

The new study also explored another important effect of rising temperatures: in-nest survival rates. Sea turtle eggs only develop successfully in a relatively narrow thermal range of approximately 25-35°C, so if incubation temperatures are too low the embryo does not develop but if they are too high then development fails. This means that if incubation temperatures increase in the future as part of climate warming, then more sea turtle nests will fail.

The researchers recorded sand temperatures at a globally important loggerhead sea turtle nesting site in Cape Verde over 6 years. They also recorded the survival rates of over 3,000 nests to study the relationship between incubation temperature and hatchling survival. Using local climate projections, the research team then modeled how turtle numbers are likely to change throughout the century at this nesting site.

Research results

Dr Laloë said: "Our results show something very interesting. Up to a certain point, warmer incubation temperatures benefit sea turtles because they increase the natural growth rate of the population: more females are produced because of TSD, which leads to more eggs being laid on the beaches.

"However, beyond a critical temperature, the natural growth rate of the population decreases because of an increase of temperature-linked in-nest mortality. Temperatures are too high and the developing embryos do not survive. This threatens the long-term survival of this sea turtle population."

The researchers expect that the numbers of nests in Cape Verde will increase by approximately 30% by the year 2100 but, if temperatures keep rising, could start decreasing afterwards.

The new study identifies temperature-linked hatchling mortality as an important threat to sea turtles and highlights concerns for species with TSD in a warming world. It suggests that, in order to safeguard sea turtle populations around the world, it is critical to monitor how hatchling survival changes over the next decades.

Dr Laloë said: "In recent years, in places like Florida--another important sea turtle nesting site--more and more turtle nests are reported to have lower survival rates than in the past. This shows that we should really keep a close eye on incubation temperatures and the in-nest survival rates of sea turtles if we want to successfully protect them.

"If need be, conservation measures could be put in place around the world to protect the incubating turtle eggs. Such measures could involve artificially shading turtle nests or moving eggs to a protected and temperature-controlled hatchery."

Climate change and temperature-linked hatchling mortality at a globally important sea turtle nesting site was published this week by Global Change Biology. Authors: Jacques-Olivier Laloë, Jacquie Cozens, Berta Renom , Albert Taxonera and Graeme C. Hays:
-end-


Swansea University

Related Climate Change Articles:

Mapping the path of climate change
Predicting a major transition, such as climate change, is extremely difficult, but the probabilistic framework developed by the authors is the first step in identifying the path between a shift in two environmental states.
Small change for climate change: Time to increase research funding to save the world
A new study shows that there is a huge disproportion in the level of funding for social science research into the greatest challenge in combating global warming -- how to get individuals and societies to overcome ingrained human habits to make the changes necessary to mitigate climate change.
Sub-national 'climate clubs' could offer key to combating climate change
'Climate clubs' offering membership for sub-national states, in addition to just countries, could speed up progress towards a globally harmonized climate change policy, which in turn offers a way to achieve stronger climate policies in all countries.
Review of Chinese atmospheric science research over the past 70 years: Climate and climate change
Over the past 70 years since the foundation of the People's Republic of China, Chinese scientists have made great contributions to various fields in the research of atmospheric sciences, which attracted worldwide attention.
A CERN for climate change
In a Perspective article appearing in this week's Proceedings of the National Academy of Sciences, Tim Palmer (Oxford University), and Bjorn Stevens (Max Planck Society), critically reflect on the present state of Earth system modelling.
Fairy-wrens change breeding habits to cope with climate change
Warmer temperatures linked to climate change are having a big impact on the breeding habits of one of Australia's most recognisable bird species, according to researchers at The Australian National University (ANU).
Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.
Older forests resist change -- climate change, that is
Older forests in eastern North America are less vulnerable to climate change than younger forests, particularly for carbon storage, timber production, and biodiversity, new research finds.
Could climate change cause infertility?
A number of plant and animal species could find it increasingly difficult to reproduce if climate change worsens and global temperatures become more extreme -- a stark warning highlighted by new scientific research.
Predicting climate change
Thomas Crowther, ETH Zurich identifies long-disappeared forests available for restoration across the world.
More Climate Change News and Climate Change Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Climate Mindset
In the past few months, human beings have come together to fight a global threat. This hour, TED speakers explore how our response can be the catalyst to fight another global crisis: climate change. Guests include political strategist Tom Rivett-Carnac, diplomat Christiana Figueres, climate justice activist Xiye Bastida, and writer, illustrator, and artist Oliver Jeffers.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Speedy Beet
There are few musical moments more well-worn than the first four notes of Beethoven's Fifth Symphony. But in this short, we find out that Beethoven might have made a last-ditch effort to keep his music from ever feeling familiar, to keep pushing his listeners to a kind of psychological limit. Big thanks to our Brooklyn Philharmonic musicians: Deborah Buck and Suzy Perelman on violin, Arash Amini on cello, and Ah Ling Neu on viola. And check out The First Four Notes, Matthew Guerrieri's book on Beethoven's Fifth. Support Radiolab today at Radiolab.org/donate.