Turtle embryos help determining their own sex


This March 2019 video says about itself:

BABY SEA TURTLE HATCHING

In summer time when the weather is warm, pregnant female sea turtles return to the beaches where they themselves hatched years before. They swim through the crashing surf and crawl up the beach searching for a nesting spot above the high water mark. Using her back flippers, the reptile digs a nest in the sand. Digging the nest and laying her eggs usually takes from one to three hours, after which the mother turtle slowly drags herself back to the ocean.

From ScienceDaily:

Turtle embryos play a role in determining their own sex

August 1, 2019

In certain turtle species, the temperature of the egg determines whether the offspring is female or male. But now, new research shows that the embryos have some say in their own sexual destiny: they can move around inside the egg to find different temperatures. The study, publishing August 1 in the journal Current Biology, examines how this behavior may help turtles offset the effects of climate change.

“We previously demonstrated that reptile embryos could move around within their egg for thermoregulation, so we were curious about whether this could affect their sex determination,” says corresponding author Wei-Guo Du, professor at the Chinese Academy of Sciences. “We wanted to know if and how this behavior could help buffer the impact of global warming on offspring sex ratios in these species.”

Du and his colleagues incubated turtle eggs under a range of temperatures both in the laboratory and in outdoor ponds. They found that a single embryo could experience a temperature gradient of up of 4.7°C within its egg. This is significant because any shift larger than 2°C can massively change the offspring sex ratio of many turtle species, Du said.

In half of the eggs, they applied capsazepine, a chemical that blocked temperature sensors, to prevent behavioral thermoregulation. After the eggs hatched, the researchers found that the embryos without behavioral thermoregulation had developed as either almost all males or almost all females, depending on the incubation temperatures. In contrast, embryos that were able to react to nest temperatures moved around inside their eggs; about half of them developed as males and the other half as females.

“The most exciting thing is that a tiny embryo can influence its own sex by moving within the egg,” Du says.

By moving around the egg to find what Richard Shine, a professor at Macquarie University of Australia and one of the co-authors, calls the “Goldilocks Zone” — where the temperature is not too hot and not too cold — the turtles can shield against extreme thermal conditions imposed by changing temperatures and produce a relatively balanced sex ratio. “This could explain how reptile species with temperature-dependent sex determination have managed to survive previous periods in Earth history when temperatures were far hotter than at present,” he says.

But this behavior has limitations, Du says, depending on the conditions of the egg and the embryo itself. “Embryonic thermoregulation can be limited if the thermal gradient within an egg is too small, or if the embryo is too large to move around or too young to have developed these abilities yet,” he says.

Additionally, the behavior cannot buffer the impact of episodes of extremely high temperatures, which are predicted to increase with climate change, Du says.

“The embryo’s control over its own sex may not be enough to protect it from the much more rapid climate change currently being caused by human activities, which is predicted to cause severe female-biased populations,” he says. “However, the discovery of this surprising level of control in such a tiny organism suggests that in at least some cases, evolution has conferred an ability to deal with such challenges.”

Du says that this study indicates that these species may have some ways not yet discovered to buffer this risk. “Our future studies will explore the adaptive significance of embryonic thermoregulation as well as the other behavioral and physiological strategies adopted by embryos and mothers to buffer the impact of climate warming on turtles.”

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Facebook censors photography museum


At the Inland Sea, Japan, by Ed van der Elsken

This 1960 photo is At the Inland Sea, Japan, by famous Dutch photographer Ed van der Elsken. It used to be on the Facebook page of the Dutch photography museum. Until Facebook censored it; along with all photos of the museum. One of many cases of Facebook censorship: from a photo showing Vietnamese children burnt by United States napalm to whistleblowing on war crimes to criticism of Donald Trump’s xenophobia. Meanwhile, the Dutch Hitler-worshiping nazis of the Nederlandse Volks-Unie are welcome on Facebook.

Translated from Dutch daily NRC Handelsblad today:

Photo museum: Facebook page offline due to nude photo by Van der Elsken

A photo by Ed van der Elsken is supposedly offensive according to the social network. They then took the entire page of the museum offline.

By Chris Koenis

The Facebook page of the Dutch photo museum was taken offline by the social network on Wednesday. One of the works of the world-famous photographer Ed van der Elsken is said to be offensive and therefore contrary to the rules of Facebook. They prohibit the posting of “Naked Material or Sexually Tinted Content.”

That photo, entitled At the Inland Sea, Japan is part of the exhibition Lust for life in the Rotterdam museum. The photo was used on the museum’s Facebook page to promote that exhibition.

Museum director Birgit Donker is indignant about Facebook‘s action. “This is a beautiful work of art that is censored by Facebook. That is contrary to their own rules. ”When the museum discovered on Wednesday that the page was ‘grayed out’, the museum reported the matter, but received no response at first.

More and more art offline

Thursday morning, a Facebook spokesperson at last contacted the museum and the corporation said that it would reconsider the decision. Until then, the Facebook page is inaccessible. That Facebook message in which Van der Elsken’s photo could be seen was not placed as an advertisement but as a regular message, the museum says.

Facebook has taken artistic photos offline more often in the past. Last year, eg, the 17th-century painting of the Descent from the Cross by Peter Paul Rubens was removed because Christ -except for his loincloth- is depicted without clothes, just like the famous prehistoric fertility sculpture Venus of Willendorf.

Other social media also sometimes delete messages. Eg, the YouTube channel of the Alkmaar Regional Archive was taken offline in June because there were images from the Second World War on the channel.

YouTube is part of the Google corporation, which does much censorship. Not just at YouTube.

Facebook censors Dutch photographer Thijs Heslenfeld: here.

COMPANIES ‘USED FACEBOOK ADS FOR AGE, GENDER DISCRIMINATION’ Seven companies violated federal law when they excluded women and older workers from seeing job ads they posted on Facebook, according to the nation’s leading employment equality watchdog. [HuffPost]

WHATSAPP IS RADICALIZING THE RIGHT IN BRAZIL Facebook famously bolstered Trump’s presidential campaign in 2016 by serving as a force multiplier for wild rumors. But a different culprit (with the same corporate parent) propelled far-right authoritarian Jair Bolsonaro to victory in Brazil’s presidential election last year: WhatsApp. [HuffPost]

Sacha Baron Cohen Slams Mark Zuckerberg For Facebook’s Latest Policy [allowing politicians to tell lies]: here.

NATOs ‘new’ Libya, refugees raped


This 1 August 2019 video says about itself:

Held in a Libyan detention centre and raped by one of the guards at the tender age of 17 is the horrid tale that Joy shares of her dreams of going to Europe.

Joy is one of more than 14,000 Nigerians who agreed to return to Nigeria after experiencing horrors in Libya.

Faith has a rather similar story, getting pregnant after being sold into sexual slavery by human traffickers in Libya.

Both women, with a third of the other women returnees, carry with them their children born out of rape. A reminder of their torment in the war-ravaged north African nation but also a light that guided them back home.

“When they come with children that are not wanted. Especially children that have been brought back being raped. Their identity is not there. It’s a lot of trauma for the mothers. We have cases where the mothers are very aggressive to these children,” said Jennifer Ero, National Coordinator of the Child Protection Network. …

Libya still holds a majority of migrants that are too scared to return to their families with the extra mouth to feed. The United Nations estimates that about 60,000 Nigerian migrants are still in Libya.

Great Barrier Reef coral trout babies study


This video says about itself:

Coral trout, Plectropomus leopardus, gather to spawn at dusk around the new moon in spring and early summer at Lizard Island on the northern Great Barrier Reef. Substantial research into the biology and ecology of this highly sought-after table fish has been conducted at the Australian Museum’s Lizard Island Research Station.

This video was shot just before sunset on 27 September 2011 at about 6 metres depth. Males wear spawning colours – very pale with a black outline – that are quite different to their normal colouration. They shimmy up to smaller females as an invitation to join a spawning rush towards the surface.

In this video, a male shimmies at several females and chases off a rival male before making a really fast spawning rush with a female at about 1 minute into the clip. Each fish emitted a puff of spawn at the apex of the rush.

This 4 December 2018 video says about itself:

Can you identify the fish swimming over the acropora coral?

Here are the fish to look our for:

Scarus ghobban – Blue-barred Parrotfish
Plectropomus maculatus – Bar-cheeked Coral Trout
Acanthurus grammoptilus – Finelined Surgeonfish
Lutjanus lemniscatus – Darktail Snapper
Labroides dimidiatus – Bluestreak Cleaner Wrasse

This video was recorded on the 9th of August 2018 at 9:08am AEST in Pioneer Bay, Orpheus Island, Australia.

From the ARC Centre of Excellence for Coral Reef Studies in Australia:

Tracking baby fish for better reef management

August 1, 2019

Summary: Scientists have created the world’s first computer model to predict the movements of baby coral trout across the Great Barrier Reef. The models are validated by in-depth fieldwork and genetic tracking, and will help managers decide which areas need the most protection to ensure future adult populations of coral trout.

A group of Australian scientists has created the world’s first computer model that can accurately predict the movements of baby coral trout across the Great Barrier Reef. The study confirms the importance of fish larvae produced in no-take zones for the health of fish populations within nearby fishing zones.

Tracking the lives of thousands of tiny baby fish is no easy task. But knowing where they’ll settle and spend their lives as adults is invaluable data for the fishing industry and reef managers.

The accuracy of the model was tested in a recent study — led by Dr Michael Bode from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University (JCU) — that validates the computer predictions with field data.

This is a world-first achievement, combining the movement of ocean currents in and around the Great Barrier Reef with the genetic and behavioural data of fish.

“The study is a unique conservation collaboration between marine biologists, geneticists, and recreational fishers,” Dr Bode said.

“This was a major field effort combined with some clever genetic work that involved matching baby fish to their parents to understand their movement,” co-author Dr Hugo Harrison, also from Coral CoE at JCU, said. “The behaviour of fish in their first few weeks after hatching can really influence where they eventually settle.”

The study focussed on coral trout, Plectropomus maculatus, which is one of the most valuable species of fish regularly caught on the Great Barrier Reef.

To test the computer model’s predictions 1,190 juvenile and 880 adult fish were tracked — from spawning locations to settlement — across the reef for two years.

The computer model recreates the movements of baby fish across space and time by considering what depth the coral trout swim at, how fast they swim, and how they orient themselves as they grow older.

The results highlighted the interconnectedness of reefs, and how important no-take zones are when considering future adult fish populations.

“Our results prove that the Great Barrier Reef’s no-take zones are connected with invisible threads,” Dr Bode said.

“Knowing how reefs are connected to one another means fishers and managers alike can identify which areas are likely to be most productive and need protecting,” Dr Harrison said. “It’s the babies from these protected areas that will continue to restock fish populations on neighbouring reefs where fishing is allowed.”

Dr Bode said establishing the accuracy of these models is an important breakthrough.

“Our match between models and data provides reassuring support for using them as decision-support tools, but also directions for future improvement.”