A new paper published at the end of October waxes dramatically over the dreaded consequences of model projections of the dreaded climate change and sea turtle reproduction.
Abstract
Sea turtles are vulnerable to climate change since their reproductive output is influenced by incubating temperatures, with warmer temperatures causing lower hatching success and increased feminization of embryos. Their ability to cope with projected increases in ambient temperatures will depend on their capacity to adapt to shifts in climatic regimes. Here, we assessed the extent to which phenological shifts could mitigate impacts from increases in ambient temperatures (from 1.5 to 3°C in air temperatures and from 1.4 to 2.3°C in sea surface temperatures by 2100 at our sites) on four species of sea turtles, under a “middle of the road” scenario (SSP2-4.5). Sand temperatures at sea turtle nesting sites are projected to increase from 0.58 to 4.17°C by 2100 and expected shifts in nesting of 26–43 days earlier will not be sufficient to maintain current incubation temperatures at 7 (29%) of our sites, hatching success rates at 10 (42%) of our sites, with current trends in hatchling sex ratio being able to be maintained at half of the sites. We also calculated the phenological shifts that would be required (both backward for an earlier shift in nesting and forward for a later shift) to keep up with present-day incubation temperatures, hatching success rates, and sex ratios. The required shifts backward in nesting for incubation temperatures ranged from −20 to −191 days, whereas the required shifts forward ranged from +54 to +180 days. However, for half of the sites, no matter the shift the median incubation temperature will always be warmer than the 75th percentile of current ranges. Given that phenological shifts will not be able to ameliorate predicted changes in temperature, hatching success and sex ratio at most sites, turtles may need to use other adaptive responses and/or there is the need to enhance sea turtle resilience to climate warming.
1 INTRODUCTION
The world’s climate is changing at an unprecedented rate (Loarie et al., 2009). As a response, species, from polar terrestrial to tropical marine environments, have started to alter their phenology (e.g., timings of cyclical or seasonal biological events), shift their geographic distribution, and modify their trophic interactions (Dalleau et al., 2012; Parmesan & Yohe, 2003; Walther et al., 2002). Species’ responses to climate change can occur through at least three contrasting but non-exclusive mechanisms: (1) range shifts, (2) phenotypic plasticity, and (3) microevolution via natural selection (Fuentes et al., 2020; Hulin et al., 2009; Waldvogel et al., 2020).
Range shifts might be observed by sea turtles responding to changes in climate by shifting their range to more climatically suitable areas (Abella Perez et al., 2016; Mainwaring et al., 2017). It is crucial that these areas provide the environment necessary for colonization and are conducive to egg incubation (Fuentes et al., 2020; Pike, 2013). However, it has been indicated that areas with climatically suitable environments might be impacted by other stressors (e.g., sea level rise, coastal development), which might hinder the potential adaptive capacity of sea turtles (Fuentes et al., 2020). Phenotypic plasticity allows individuals to cope with environmental changes and relates to the ability of individuals to respond by modifying their behavior, morphology, or physiology in response to an altered environment (Hughes, 2000; Hulin et al., 2009; Waldvogel et al., 2020). Microevolution refers to adaptation occurring because of genetic change in response to natural selection (Lane et al., 2018). Phenotypic plasticity provides the potential for organisms to respond rapidly and effectively to environmental changes and thereby cope with short-term environmental change (Charmantier et al., 2008; Przybylo et al., 2000; Réale et al., 2003). However, phenotypic plasticity alone may not be sufficient to offset against projected impacts from climate change (Gienapp et al., 2008; Schwanz & Janzen, 2008). Microevolution, on the other hand, is thought essential for the persistence of populations faced with long-term directional changes in the environment. However, the ability of microevolutionary responses to counteract the impacts of climate change is unknown, because rates of climate change could outpace potential responses (Hulin et al., 2009; Morgan et al., 2020; Visser, 2008) although see Tedeschi et al. (2015).
It is unclear whether potential adaptive responses by turtles will be sufficient to counteract projected impacts from climate change (Monsinjon, Lopez-Mendilaharsu, et al., 2019; Moran & Alexander, 2014; Morjan, 2003). For example, sea turtles have persisted through large changes in climate during the millions of years that they have existed, demonstrating a biological capacity to adapt (Maurer et al., 2021; Mitchell & Janzen, 2010; Rage, 1998). Nevertheless, there is growing concern over the potential impacts that projected temperature increases might have on sea turtles (Patrício et al., 2021). Temperature plays a central role in sea turtle embryonic development, hatching success, hatchling sex ratios (Hays et al., 2017; Standora & Spotila, 1985), hatchling morphology, energy stores, and locomotor performance (Booth, 2017). Sea turtle eggs only successfully incubate within a narrow thermal range (25 and ~35°C), with incubation above the thermal threshold resulting in hatchlings with higher morphological abnormalities and lower hatching success (Howard et al., 2014; Miller, 1985). Furthermore, sea turtles have temperature-dependent sex determination, a process by which the incubation temperature determines the sex of hatchlings (Mrosovsky, 1980). The pivotal temperature (PT ~28.9–30.2°C for the species studied here, Figure S1), where a 1:1 sex ratio is produced, is centered within a transitional range of temperatures (~1.6–5°C, Figure S1), that generally produces mixed sex ratios. Values above the PT will produce mainly female hatchlings while values below produce mainly males (Mrosovsky, 1980).
Thus, projected increases in temperature may cause feminization of sea turtle populations and decrease reproductive success (Patrício et al., 2021). Many studies have suggested that sea turtles may adapt to increases in temperature by altering their nesting behavior, through changes in their nesting distribution, and nest-site choice (Kamel & Mrosovsky, 2006; Morjan, 2003), and by shifting nesting to cooler months (Almpanidou et al., 2018; Dalleau et al., 2012; Pike et al., 2006; Weishampel et al., 2004). Earlier nesting has already occurred in some turtle populations as a response to climatic warming (e.g., Pike et al., 2006; Weishampel et al., 2004). However, it is unclear whether phenological and behavioral shifts can sufficiently buffer the effects of rising temperatures (Almpanidou et al., 2018; Laloë & Hays, 2023; Monsinjon, Lopez-Mendilaharsu, et al., 2019). Although two other studies (Almpanidou et al., 2018; Laloë & Hays, 2023) have explored whether earlier shifts in phenology can preserve the present-day thermal niche of sea turtle nesting environment in a changing climate, only one other study (Monsinjon, Lopez-Mendilaharsu, et al., 2019) explores the implications of phenological responses to sea turtle reproductive output (hatching success and primary sex ratio), of which they focused on loggerhead turtles (Caretta caretta). Given that different sea turtle species have different spatial–temporal nesting patterns, we expand from this study focused on loggerhead turtles to assess the extent to which phenological shifts by four different species of sea turtles could mitigate increases in temperature at different sea turtle nesting sites globally to maintain the reproductive output of affected populations. Furthermore, to build on previous work, we explore whether nesting populations could benefit from both an earlier and a later phenological shift. To do so, we calculated the shift (backward and forward, respectively) that would be required for incubation temperature, hatching success, and sex ratio to stay similar to current ranges. In doing so we are the first study to date to investigate the implications of a later nesting by sea turtles.
https://onlinelibrary.wiley.com/doi/10.1111/gcb.16991
I know that the study is making predictions or projections decades out, but other activist scientists, a caterwauling media, and compliant politicians all tell us, screw the models, we are currently in the throes of a CLIMATE CRISIS already!!!! Everything is suffering!
Hottest July ever signals ‘era of global boiling has arrived’ says UN chief
How the climate crisis is changing hurricanes
Warming Oceans Are Making the Climate Crisis Significantly Worse
And now reality. Let’s check in on how those sea turtles are handling the boiling oceans and super rapidly intensifying super hurricanes.
South Florida beaches in Broward County saw a record number of leatherback sea turtle nests this year.
Leatherback sea turtles laid a record 79 nests along the beaches of Broward County in 2021, almost double the number of nests from the previous record, according to the South Florida SunSentinel. The previous record was 46 nests in 2012.
Florida county beaches see record number of sea turtle nests this year
LMC has currently documented 21,020 nests: 215 from leatherbacks, 14,469 from loggerheads, and 6,336 from green turtles. All of these species are of sea turtles are threatened or endangered.
The center’s researchers attribute the boost in numbers to successful conservation efforts over the past few decades.
Loggerhead Marinelife Center director of research speaks about record-breaking number of sea turtle nests
Last year, the total number of sea turtle nests was an impressive 18,132, but that number has just been blown out of the water with tons of nesting nights still to go in the 2024 season, according to the vice president of research at Loggerhead Marine Life Center, Dr. Justin Perrault.
“We have officially broken the nest record. As of today, we have 21,666 sea turtle nests,” he said.
….
Believe it or not, there are still three whole months left of nest season, so Perrault is predicting a grand total of 27,000 nests come November.
Record broken for most sea turtle nests ever in Palm Beach County
FORT LAUDERDALE, Fla. – Biologists were taken by surprise by a record number of leatherback turtle nests found along some South Florida beaches this year.
The 79 nests laid by endangered turtles along beaches in Broward County this year is nearly double the previous record, the South Florida Sun Sentinel reported. The previous record was 46 in 2012, and the record low for leatherback nests was 12 in 2017.
South Florida beaches see record year for sea turtle nests
Sea turtles in Florida are handling the climate crisis quite well.
…sea turtles have persisted through large changes in climate during the millions of years that they have existed, demonstrating a biological capacity to adapt Nevertheless, there is growing
concernalarmism over the potential impacts that projected temperature increases might have on sea turtlesFIFY
Exactly. My first response was, how did they survive past interglacial periods where temperature was warmer than today? The second thought is that, along the Texas coast, our sea turtle patrols collect the eggs of the endangered Kemp’s Ridley sea turtle and transport them to a National Park hatchery on Padre island where they are incubated at a temperature warm enough to favor females (I serve as an egg transporter). There are enough males hanging out offshore to do their job.
It was never warmer than today. Never, ever, ever, ever,……………ever.
hmmmm…. concern…. potential…. projected…. might….
Modern science.
These papers are utter nonsense.
First of all, the warmunists focus on atmospheric air temperatures – i.e., “climate”, but it is the oceans that are the heat sink for the planet,not the atmosphere. Given that humongous ratio of mass of the oceans compared to the mass of the atmosphere, and the much larger specific heat content of water compared to air – which means that it takes a whole lot more energy to raise the temperature of water by 1 deg C than it does to raise the air temp by the same amount, it is extremely unlikely that oceanic water temperatures are going to increase by any reasonably detectable number of degrees given that the warmunists are caterwauling about just 0.5 deg C additional warming over current atmospheric temps.
Not to mention that animals always adapt to their environment, if need by by relocating themselves. Even if Florida oceanic temperatures increased by, say 0.1 deg C, and that somehow impacted sea turtles, then they only need move a short ways up the Atlantic coast to get to more favorable conditions. A specific animal may not relocate itself, but if the animals off the coast of Georgia have more favorable conditions for reproduction than they do in south Florida, then those animals will see increased populations even if south Florida’s populations decrease a little.
And how does more females reduce the fecundity of the population?
It’s just not logical, Captain.
And even if it is a problem, why not move somewhere cooler.
When I lived in Seattle I was surprised to sea both turtles and humming birds in a Seattle winter, neither of which I have ever seen at the same latitude in the UK.
Maybe we should introduce these ‘invasive’ species?
Who, exactly, is expressing ‘concern’ and how has it been determined that this ‘concern’ is ‘growing’?
I suspect that the average sea turtle has more common sense than the numerous authors of this paper put together; if conditions at one nesting site become unattractive, they’ll find somewhere else.
“Who, exactly, is expressing ‘concern’ and how has it been determined that this ‘concern’ is ‘growing’?”
Those are the kinds of questions I would be asking.
Skeptics want details! 🙂
“Values above the PT will produce mainly female hatchlings”
One female can produce one clutch of eggs annual.
One mail can fertilise ??? femailes?
So higher temperatures,
= higher female ratio = more eggs = more hatchlings = more turtles.
And this is a threat to populations how?
…annually … females
(Please bring back the edit function, if only for a minute of so)!!!….
The idea is that if the temperature goes up then all eggs will hatch as females and there will be no males to fertilise the eggs. This idea fails to take into account that not all eggs are laid in the same place or the same time; if eggs are laid in a slightly cooler part of the season, or in a more sheltered, cooler area then this will favour male hatching instead. Hand-wringing emotional alarmism from an ill-educated bunch of idjits.
Since turtle soup is now illegal in the USA, I’m guessing the turtles will adapt very well, to any real or imagined slight changes to their environment.
The turtle soup at the Bon Ton Cafe in New Orleans was excellent. It’s closed now but there still is Brennan’s. It’s on top of the appetizer list. https://www.brennansneworleans.com/menus/dinner/
Some farmed species of turtle are still legal to eat but most wild species are endangered so yes, illegal. The problem is, apparently, that turtles are quite tasty – presumably that’s why the armour plating.
Yeah turtle soup is very good….my bride never had a spoonful until one night in New Orleans and it’s now at the top of her order!
Never had turtle soup but I did have fried fresh turtle meat from a snapping turtle. Very good.
The white meat tasted more like chicken and the red meat more like beef.
That’s what they say – you can get about 4 different types of meat from a turtle, chicken and beef being just two of them.
The turtles have had a good year in North Florida. I walked by one on the beach yesterday. We see the turtle keepers examining sites routinely. We can be good stewards if we prioritize and compromise.
Now if we can prevent the proliferation of windfarms we might save some birds of prey and a few whales.
I’ve looked for signs of global warming along the Southeastern coasts for decades. I don’t see it. Sandbars come and go. Coastal weather is finicky. Day to day, year to year. This year the summer was hot and wet. Last year, not so much. Yes we have flooding. The city is over 400 years old. Construction crews discovered a boat from the 19th century a few days ago.while working on a drainage project.
Humans adapt to slow incremental change. Apparently turtles do as well.
This adaptation you speak of must be something new. No, wait. Humanity has a 300,000 year history of adaptation and each person is the result of 1000s of generations of success at adaptation. Weird that we are projected to suddenly stop adapting. One wouldn’t think that two degrees C was such a big deal, given the environments we existed in before technology allowed us to live everywhere, including in orbit for over a year.
As a species we adapted to living through an ice age so a bit of warmth will be fine. It would be weird if it wasn’t for the money these people are getting for writing this guff.
My understanding is that sea turtles have been in existence for 100million years. The CAGW crowd is sweating a 2.0 C increase in average global temperature from pre industrial times. By their own admission they claim we have already experienced a 1.2 C increase. I can’t imagine a scenario where sea turtles couldn’t handle another 0.8 C increase in the next 80 some years. Common sense would have us believe they will be fine.
If the turtles proliferate at the rate the number of ‘authors’ who write about them profileritilittletittletattletillerate – Turtle Soup **will** have to be on *everyone’s* menu – we’ll be over-run else not
<it’s worse than anyone thought>
The Gulf of Mexico is already hitting the 30C limit. That is all it can sustain. Once it overshoots the limit, the maximum convective towers form and pull the heat out of the ocean to redistribute to higher latitudes. This year the Pacific was more dominant and tended to form the convective storms that pulled mid-level moisture out of the Gulf of Mexico.
As more northern ocean surface reaches the 30C limit in September, there is more moisture over land in October that comes down as snow in November. Those living north of 40S should enjoy lots of “global warming” this month. Because the only way to get more snow is to increase heat advection from the oceans, which brings moisture with it. Increasing snowfall in the NH is what “global warming” looks like. It is most evident in January on the Greenland Plateau where temperature is increasing at 9C/century and the island is gaining elevation at the rate of 17mm a year.
Gulf temps have not increased at all in the nearly 40 years that I’ve lived here. Mid summer Gulf water temps have always been 89-90 deg F. Dropping to the low to mid 60s in mid winter. There is absolutely nothing special or remarkable or determinative about 30 deg C/86 deg F Gulf water temps in the summer.
ORT LAUDERDALE, Fla. – Biologists were taken by surprise by a record number of leatherback turtle nests found along some South Florida beaches this year.
But….But…the science was settled?
“Climate Scientists” seem to frequently be in a state of surprise these days when their prognostications of catastrophe are proven false. But it doesn’t stop them from doubling down with more of their bull hockey. Usually after a short period of silence to allow their alarmist believers memories to lapse so they can recycle the same crap again.
“warmer temperatures causing lower hatching success and increased feminization of embryos”
OMG! And soon, it might cause more of your children to be gay, according to the average of 97 models! /sarc
Well that part is true; turtles, crocodiles and some other egg-laying species are temperature-sensitive when it comes to the hatchlings sex. However, saying that, it has become overused and abused since it was discovered – these ‘scientists’ should be more reasoned and objective, far less emotional and hand-wringingly sensitive.
So … female turtles are HOT!
I doubt the male turtles will mind. 😎
Female turtles are hot and male turtles are cool.
One main reason for the increase is the passing of lighting laws that require lights along the nesting beaches to be reduced/hidden so that the hatchlings do not get confused as to where the water is. This has increased the survival rate of hatchlings which then return to their birth place in higher numbers.
It is a wonderful sight when walking along a beach and seeing fresh tracks where the turtles came ashore, created a nest then returned to the water perhaps only an hour or so prior.
Rush Limbaugh used to talk about having to turn his lights off during this season. He wasn’t complaining. He liked turtles.
The new laws in Colorado banning one-time use plastic bags and even plastic soda straws obviously helped increase turtle reproduction 2,000 miles away in Florida! The science is settled. heh heh Of course, incidences of bacterial and viral infections from the “re-useable” shopping bags are on the increase, but it’s worth it to save the turtles, huh?
Florida has done very well supporting the turtles. The great publicity we have here concerning nesting, plus “walkovers” and signs in the dunes helps protect the nests. The lighting thing is also a biggie.
One biggie that is not seen here or those beaches in south Texas is collecting and eating the eggs! Our special operations troops stationed here that deploy to central america have seen the indigenous folks at some beaches there collecting the turtle eggs for food. Nevertheless, the turtles keep on coming up here and we have super places along the Gulf and Atlantic to accomodate the critters, as the stats indicate this year.
On the subject of tribulations faced by sea turtles, it’s worth remembering that only a few months ago the BBC, home of ‘BBC Verify’ and a small army of mis- and disinformation correspondents, was forced to publicly admit by its Executive Complaints Unit that it chose a doctored image to scaremonger its audience.
The original photo was taken by Jakob Gojda:
The BBC’s ECU was finally forced to admit the image breached its Standards of Accuracy.
So the so-called “defenders of truth” are spreading disinformation.
I can’t say I’m surprised.
Again.
How many more times will this happen with the BBC just getting a mild slap on the wrist until something is done? Things like this are now a regular ocurrence, not an isolated incident.
According to these authors, the sand temperatures for incubation of sea turtle eggs needs to be between 25 C and 35 C, and the researchers are worried about an increase in sand temperatures from 0.58 to 4.17 C by the year 2100.
Sand temperatures are likely below 25 C (77 F) for most of the late autumn and winter (November through March), due to the lower sun angle and longer, cooler nights, so that the sea turtle eggs need to incubate during the spring and summer months.
Along the east Florida coast, from late May through September, the mornings are usually sunny, but clouds build up during midday, and there are often rain showers or thunderstorms in the afternoon. This would mean that sand temperatures would reach a maximum shortly before the clouds arrive, but rainwater soaking into the sand would cause a sudden drop in temperatures, and sand temperatures would be lower at night without solar heating.
This means that under present conditions, sand temperatures can vary by 5 C or more within a single day, without having to wait another 77 years until the year 2100. If the baby turtles can handle such fluctuations over the many days they are growing and developing in the eggs, they can handle a slight increase in “average” sand temperatures over the next 77 years.
Did these researchers put temperature probes into turtle nests to continuously monitor the sand temperature? Did they also record maximum and minimum sand temperatures, including during rainy weather, not just “average” temperatures in sunny weather, during the incubation period?
The researchers also claim that higher sand temperatures favor female baby turtles over male baby turtles. Since the sex of a turtle embryo is determined at the moment of fertilization, does this mean that higher sand temperatures tend to kill more male baby turtles in the egg than female baby turtles?
There are many high-rise condominium complexes along the barrier islands on the east coast of Florida, and many of them have regulations that prohibit residents from shining artificial light on the beaches at night between March and November, in order to protect sea turtles. Presumably, if the hatchlings emerge from the egg at night, and have to quickly walk into the sea, keeping the beach dark prevents them from being seen by predators.
But there are many threats to a baby sea turtle in its first hour of life outside the egg. If it hatches at low tide, it has a longer walk to the sea than at high tide. If it emerges on a moonlit night, it can be seen by predators even if there is no artificial light. These threats are far more deadly than a slight increase in average sand temperature over the next 77 years!
“Since the sex of a turtle embryo is determined at the point of fertilisation…” Completely incorrect – Turtles, Crocodiles and Alligators all have TSD; Temperature-dependant Sex Determination, meaning that the sex of an embryo is only determined part-way through development, well after fertilisation, and is dependant on the sand temperatures as to whether they hatch as male or female.
Could be worse; some frogs have the ability to change from being male to being female during their adult life, determined solely by the male to female ratio in the local population. Life can get so weird sometimes.
Thank you Richard, was wondering about that myself, especially after seeing Jurassic Park’s doc explain how the critteres were reproducing……
Main reason I post again is the beachfront lighting doen’t make it easier for predation, but it prevents confusion by the young turtles who head toward the light after hatching. So we have been keeping the lights off as much as possible during the summer. Seems to be working.
Additionally we don’t make turtle soup using sea turtles, but from freshwater bayou, swamp and pond turtles.
Gums sends…
Michael Crichton was a great author but he did sometimes assume a level of obscure knowledge on the part of his readership. I’ve had to put books of his down while I look stuff up before now.
“The world’s climate”
I am no scientist but even I can see these opening words as designed for emotive purposes.
There is no ‘world’ climate, only local ones and many disparate ones.