Fossil sea turtle baby, new research


Tasbacka danica, photo by Johan Lindgren

From North Carolina State University in the USA:

Keratin, proteins from 54-million-year-old sea turtle show survival trait evolution

October 17, 2017

Researchers from North Carolina State University, Lund University in Sweden and the University of Hyogo in Japan have retrieved original pigment, beta-keratin and muscle proteins from a 54 million-year-old sea turtle hatchling. The work adds to the growing body of evidence supporting persistence of original molecules over millions of years and also provides direct evidence that a pigment-based survival trait common to modern sea turtles evolved at least 54 million years ago.

Tasbacka danica is a species of sea turtle that lived during the Eocene period, between 56 and 34 million years ago. In 2008 an extremely well-preserved T. danica hatchling was recovered from the Für formation in Jutland, Denmark. The specimen was less than 3 inches (74 millimeters) long. In 2013 paleontologist Johan Lindgren of Lund University uncovered soft tissue residues from an area located near the sea turtle’s left “shoulder.” He collected five small samples for biomolecular analysis.

The shells of modern sea turtle hatchlings are dark colored — this pigmentation gives them protection from aerial predators (such as seagulls) as they float on the ocean surface to breathe. Since turtles are reptiles, and therefore cold-blooded, the dark coloration also allows them to absorb heat from sunlight and regulate their body temperature. This elevated body temperature also allows more rapid growth, reducing the time they are vulnerable at the ocean surface.

The T. danica hatchling specimen appeared to share this coloration with its living counterparts. The researchers observed round organelles in the fossil that could be melanosomes, pigment-containing structures in the skin (or epidermis) that give turtle shells their dark color.

To determine the structural and chemical composition of the soft tissues Lindgren collected and see if the fossil sea turtle did have a dark colored shell, the researchers subjected the sample to a selection of high-resolution analytical techniques, including field emission gun scanning electron microscopy (FEG-SEM), transmission electron microscopy (TEM), in situ immunohistochemistry, time-of-flight secondary ion mass spectrometry (ToF-SIMS), and infrared (IR) microspectroscopy.

Lindgren performed ToF-SIMS on the samples to confirm the presence of heme, eumelanin and proteinaceous molecules — the components of blood, pigment and protein.

Co-author Mary Schweitzer, professor of biological sciences at NC State with a joint appointment at the North Carolina Museum of Natural Sciences, performed histochemical analyses of the sample, finding that it tested positive against antibodies for both alpha and beta-keratin, hemoglobin and tropomyosin, a muscle protein. TEM, performed by University of Hyogo evolutionary biologist Takeo Kuriyama, and Schweitzer’s immunogold testing further confirmed the findings.

In the end, the evidence pointed to these molecules as being original to the specimen, confirming that these ancient turtles shared a pigmentation-based survival trait with their modern-day brethren.

“The presence of eukaryotic melanin within a melanosome embedded in a keratin matrix rules out contamination by microbes, because microbes cannot make eukaryotic melanin or keratin,” Schweitzer says. “So we know that these hatchlings had the dark coloration common to modern sea turtles.

“The data not only support the preservation of multiple proteins, but also suggest that coloration was used for physiology as far back as the Eocene, in the same manner as it is today.”

The scientific report on this is here.

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Sea turtle conservation works


This video says about itself:

8 May 2012

In Malaysia there is an island known for more sea turtles than virtually anywhere on Earth. Jonathan visits this amazing ecosystem to learn about the life cycle of sea turtles. He is surprised to discover an amazingly complex and competitive environment.

From the American Association for the Advancement of Science in the USA:

Efforts to save sea turtles are a ‘global conservation success story’

September 20, 2017

A new study of the world’s seven sea turtle species provides evidence that their numbers are growing overall (unlike many endangered vertebrates), thanks to years of conservation efforts that have played a key role in sea turtle recovery — even for small sea turtle populations. Sea turtles have historically suffered population declines for reasons that include accidental catch and harvesting adults and eggs.

Such decreases have motivated worldwide conservation efforts since the 1950s to employ tactics like strict fishing regulations and beach protection measures. To examine the current global status of sea turtles, Antonios Mazaris and colleagues studied 4,417 annual estimates of sea turtle nesting abundance based on specific time periods of nesting data collection that ranged in length from six to 47 years.

They used estimates from 2010 or later to evaluate the length of time periods required to detect significant trends in abundance within Regional Management Units (which represent discrete groups of nesting sites in certain areas that are distinct from one another based on genetics, distribution, movement, and demography) for each species, finding a majority of population increases (95 significant increases compared to 35 significant decreases).

Despite the encouraging upward population trends, Mazaris et al.’s results complement International Union of Conservation for Nature (IUCN) assessments of sea turtle status, which lists six sea turtle species as endangered.

The authors also found that while longer time periods of nesting data collection are important for detecting population trends, shorter intervals not currently used by IUCN could still provide important information, though they highlight the need for more updated and continuous nesting site information.

Snail hitchhiking on terrapin, video


This video from South Africa says about itself:

31 May 2017

Unbeknown to it, this Terrapin was hitchhiking a snail, much to the amusement of Franscois and his guests! Video by Franscois Rosslee.

US Trump administration endangers whales, turtles


This video from the USA says about itself:

Trump Administration Makes It Easier To Kill Endangered Whales

13 June 2017

This week in ‘Evil Things the Trump Administration is Doing,’ they’ve now made it easier to kill endangered whales. John Iadarola, Hannah Cranston, and Kim Horcher, the hosts of The Young Turks, tell you why.

“SAN FRANCISCO — The Trump administration on Monday threw out a new rule intended to limit the numbers of endangered whales and sea turtles getting caught in fishing nets off the West Coast, saying existing protections were already working.

Economically, the new rule would have had “a much more substantial impact on the fleet than we originally realized,” said Michael Milstein, a spokesman with the federal fisheries service, which killed the rule.

The rule would have applied to fewer than 20 fishing vessels that use mile-long fishing nets to catch swordfish off California and Oregon. The change would have shut down the drift gillnet fishing for swordfish for up to two seasons if too many of nine groups of whales, sea turtles or dolphins were getting caught in the nets.”

Read more here.

Green turtle video


This video says about itself:

Green Turtle‘s Battle For Survival – Planet Earth – BBC Earth

From the moment they are born, these plucky Green Turtles from Ascension Island will face a huge battle to survive. Those that do survive, like their mothers did before them, will return to exactly same beach where they hatched.

Sea turtles and climate change


This video from Mexico says about itself:

6 March 2010

Baby leatherback turtles emerged from their eggs and nests this morning and made their painstaking way to the Sea of Cortez.

From Science News:

Hot nests, not vanishing males, are bigger sea turtle threat

Climate change killing nestlings with heat could be worse than sex ratios going too female

By Susan Milius

7:05pm, February 7, 2017

Worries about climate change threatening sea turtles may have been misdirected.

Warming that could lead to far more female hatchlings than males isn’t the most immediate danger from climate shifts. Lethally overheated beach nests are more important, researchers argue February 8 in Proceedings of the Royal Society B.

Climate change can meddle with sex ratios of the seven species of sea turtles because their embryos start life without a genetically fixed sex. Nest temperatures greater than roughly 29° Celsius tip the ratio toward more female hatchlings, explains marine ecologist Graeme Hays of Deakin University in Warrnambool, Australia.

Warm the nesting beaches enough, and sea turtle populations with few to no male mates might get feminized to extinction, biologists have warned. Yet records from 75 sea turtle nesting sites around the world suggest that many still-abundant populations are skewed to extreme female bias. “That’s not really the No. 1 concern,” Hays says. “A few male turtles already go a long way.” Instead, youngsters dying in overheated nests appears to be a more serious problem and needs a worldwide effort at data collection, Hays and colleagues say.

One reason heavily female turtle populations haven’t crashed yet is the difference between male and female breeding frequency, the researchers say. A male shows up to mate in the waters off the nesting beach roughly twice as frequently as a female does, perhaps every two years instead of every four, Hays says.

Disproportionately higher death rates among female hatchlings also could temper the female bias generated by upward creeping nest temperatures. Warmer spots in nesting beaches that are more likely to make embryos turn female are also more likely to cook them.

At extreme temperatures, however, everybody loses. Should a nest reach 35° C, a group of 100 eggs would yield on average only five living female hatchlings plus a ghost of a fraction of a male, mathematical simulations predict.

Vincent Saba has seen hatchling losses firsthand at the leatherback turtle nesting site he studied in Costa Rica. There, computer simulations suggest that as the beach overheats the dwindling survival of young turtles could nearly wipe out the population within a century, says Saba, a biological oceanographer with the National Oceanic and Atmospheric Administration’s Northeast Fisheries Science Center at Princeton University.

Just how much a beach heats up depends largely on rainfall, which in turn depends on how the climate changes, says Saba. Sorting out the effects on sea turtle populations is going to take science done “beach by beach.”

Rare olive ridley turtle beaches in Wales


This video says about itself:

7 Wonders of India: Olive Ridley Sea Turtles

6 February 2009

Found in the Indian Ocean along the Bay of Bengal is Orissa. Average weight of the turtles is just over 100 lb (up to 50 kgs). They have a high-domed shell, with a carapace length of only 30 inches (70 cms). Olive Ridleys are omnivorous, feeding on crabs, shrimp, rock lobsters, sea grasses, snails, fish, sessile or pelagic tunocates and small invertebrates.

The Orissa coast is one of the three sites worldwide where mass nesting of the Olive Ridley Turtle occurs. This sea turtle is especially known for its mass nesting when several thousand turtles migrate to the breeding ground to mate and nest simultaneously. Hindu mythology worships sea turtles as an incarnation of one of their gods. Over the past five years, sea turtles have suffered mass mortality along the Orissa coast due to death by drowning as incidental catch in trawl – fishing nets. About 5,000 to 10,000 dead turtles have been washed ashore each year, a total of over 100,000 in the last 10 years.

By Peter Frost in Britain:

A rare visitor washes up on Britain’s shores

Friday 3rd February 2017

Sea turtles are coming ashore in increasing numbers. But we’ve now had a rare visitor, writes PETER FROST

AN OVER two-foot long rare olive ridley sea turtle (Lepidochelys olivacea) came ashore on an Anglesey beach last November.

It was the first ever example of this very rare species to be found alive on a British beach. Local people nicknamed the turtle Menai.

The animal was in poor condition, she was severely hypothermic when found stranded.

She was around 15,000 miles from her usual habitat, warm and tropical waters, primarily in the Pacific and Indian Oceans.

The stranded turtle was looked after at Anglesey Sea Zoo and then taken 400 miles by road to Hertfordshire’s Royal Veterinary College for a CAT scan and more sophisticated care.

The aim is to get her fit enough to be returned to the wild. The scans discovered Menai has gas inside her carapace, making it difficult for her to submerge and swim underwater. She is also suffering lung damage.

But experts who are caring for Menai called the results “good news.” “There are no huge worries,” Anglesey Sea Zoo director Frankie Hobro told us.

“We are happy now that we know what the problem is. We can now research what treatment she needs to recover. The next stage is to drain the gas and correct her buoyancy problems.”

Menai is the first olive ridley turtle to be sighted in Britain since records began in 1748. Now olive ridley turtle experts are planning her rehabilitation and hope to release her back into the wild.

The olive ridley is the second smallest sea turtle after the very closely related Kemp’s ridley. Olive ridleys weigh between 75-100 pounds and reach 2-2 ½ feet in length.

They are named for their pale green carapace or shell and are the most abundant of all sea turtle species.

Olive ridleys occur globally and are found mainly in tropical regions of the Pacific, Indian and southern Atlantic Oceans.

They are primarily pelagic, spending much of their life in the open ocean but may also inhabit bays and estuaries.

Some olive ridleys lay eggs on solitary beach sites but some come together for huge and spectacular beach invasions where thousands of females land on the same beach at the same time to lay their eggs. These spectacular mass-egg layings are called arribadas (“arrival” in Spanish).

Strangely there are only a few places in the world where olive ridley arribadas occur. In other parts of the world, they are solitary nesters.

Though arribadas are not well understood; the timing may coincide with weather events such as strong winds or cloudy days, or with moon and tide cycles.

The turtles congregate in large groups offshore of nesting beaches and then simultaneously come ashore to nest.

Females may remain offshore near nesting beaches throughout the nesting season.

These turtles eat a variety of prey including crabs, shrimp, lobster, urchins, jelly fish, algae and fish.

Despite their relative abundance in comparison to other sea turtles, olive ridleys are considered vulnerable by the International Union for Conservation of Nature’s Red List and are listed as threatened in the US.

Although they are still the most abundant species, their numbers have decreased by approximately half since the 1960s.

Historically, the olive ridley has been hunted for food, bait, oil, leather and fertiliser.

The meat is not considered a delicacy. The eggs however are said to be delicious and have always been a valuable commodity. Egg collection is illegal in most of the countries where olive ridleys nest, but these laws are rarely strictly enforced.

Legal egg harvesting has been allowed in several localities. Perhaps the biggest is in Ostional, Costa Rica, where villagers have been able to harvest and sell around three million eggs each year.

Over 27 million eggs are left un-harvested and villagers claim they play a large role in protecting these nests from predators, thereby increasing hatching success.

In most other regions, illegal poaching of eggs is considered a major threat to olive ridley populations and attracts much criticism from conservationists and sea turtle biologists.

As well as egg digging, other major threats to the turtle include degradation of nesting beaches, particularly in India where large commercial coastal developments threaten traditional turtles nesting sites.

Many of their nesting beaches have already been destroyed by coastal development and subsequent erosion.

Other threats include the direct harvest of turtles and eggs for human consumption and the accidental capture of turtles in commercial fishing gear.

It is estimated that more than 60,000 sea turtles, mainly olive ridleys, are caught and drowned in commercial shrimp trawl nets each year.

Over the last few years, winter storms have led to a steep rise in the number of turtles being washed up on our British beaches.

Last winter, a total of 16 warm-water turtles — some critically endangered — were found on the British shoreline, the highest total since 2008 according to environmental groups.

Most of the comatose turtles washed up are juveniles, less able to cope with strong waves, and they are usually starving and suffering from hypothermia.

Here is some advice for those taking winter walks on our beaches who may find a sea turtle washed up by recent gales.

The reptiles can’t stand the cold weather, which shuts them down and they eventually wash up on our shores.

When they wash up they are so moribund that, to the casual observer, they may appear to be dead but actually they may still be alive, and with expert care can be rescued and nurtured back to health to make a full recovery.

Under no circumstances should turtles be put back into the sea, as the thermal shock from the cold waters would certainly kill them.

You should immediately report any stranded animals to the RSPCA.