A new Swansea University study has suggested that warming temperatures could drive sea turtles to extinction.
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.
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
Delyth Purchase | EurekAlert!
Don't Give the Slightest Chance to Toxic Elements in Medicinal Products
23.03.2018 | Physikalisch-Technische Bundesanstalt (PTB)
North and South Cooperation to Combat Tuberculosis
22.03.2018 | Universität Zürich
Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.
The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...
An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.
The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
23.03.2018 | Event News
19.03.2018 | Event News
16.03.2018 | Event News
23.03.2018 | Life Sciences
23.03.2018 | Materials Sciences
23.03.2018 | Process Engineering