Fossil prehistoric amphibians died young


This 2011 video is called 360 Million Year Old Tetrapod Acanthostega.

From Science News:

Preteen tetrapods identified by bone scans

Improved technique suggests large four-limbed Acanthostega were still juveniles

By Susan Milius

1:00pm, September 7, 2016

Better bone scanning of fossils offers a glimpse of preteen life some 360 million years ago.

Improved radiation scanning techniques reveal accumulating growth zones in chunks of four fossil upper forelimb bones from salamander-shaped beasts called Acanthostega, scientists report online September 7 in Nature. Vertebrate bones typically show annual growth zones diminishing in size around the time of sexual maturity. But there’s no sign of that slowdown in these four individuals from East Greenland’s mass burial of Acanthostega, says study coauthor Sophie Sanchez of Uppsala University in Sweden. They were still juveniles.

The bones came from tropical Greenland of the Devonian Period. Aquatic vertebrates were developing four limbs, which would serve tetrapods well when vertebrates eventually conquered land. This mass die-off doomed at least 20 individuals, presumably when a dry spell after a flood trapped them all in a big, vanishing puddle.

This find makes the strongest case yet for identifying genuine youngsters among ancient tetrapods, Sanchez says. She suspects other individuals trapped could have been juveniles too.

Not many other species were found in the mass burial. So young tetrapods may have stuck together much as today’s young fish schools, Sanchez speculates. The limb shape clearly indicates that the youngsters took a long time to start adding hard bone to the initial soft cartilage, she says. So these early tetrapods were at least 6-year-olds and probably 10 years old or more.

For identifying stages of life, the improved technique “allows greater resolution and rigor, so in that regard it is a plus,” says Neil Shubin of the University of Chicago, who studies a fossil fish with some tetrapod-like features called Tiktaalik. There are Tiktaalik preteens, too, he notes.

What interests Nadia Fröbisch of Museum für Naturkunde in Berlin is that some of Acanthostega individuals were different sizes but had reached the same stage of bone development. She muses that they might even have been developing along different trajectories of growth, a flexibility that would be useful in a changeable environment.

3,700-million-year-old life discovery in Greenland


This video says about itself:

The world’s oldest fossil: 3.7 billion year old bumps found on ancient sea bed

31 August 2016

Conical structures known as stromatolites were found in Isua, Greenland.

They were formed by prehistoric colonies of bacteria living in a shallow sea.

It suggests life may have emerged on Earth far faster than first thought.

The finding raises hopes life may have existed on Mars.

From Nature:

Rapid emergence of life shown by discovery of 3,700-million-year-old microbial structures

Published online 31 August 2016

Biological activity is a major factor in Earth’s chemical cycles, including facilitating CO2 sequestration and providing climate feedbacks. Thus a key question in Earth’s evolution is when did life arise and impact hydrosphere–atmosphere–lithosphere chemical cycles? Until now, evidence for the oldest life on Earth focused on debated stable isotopic signatures of 3,800–3,700 million year (Myr)-old metamorphosed sedimentary rocks and minerals1, 2 from the Isua supracrustal belt (ISB), southwest Greenland3.

Here we report evidence for ancient life from a newly exposed outcrop of 3,700-Myr-old metacarbonate rocks in the ISB that contain 1–4-cm-high stromatolites—macroscopically layered structures produced by microbial communities. The ISB stromatolites grew in a shallow marine environment, as indicated by seawater-like rare-earth element plus yttrium trace element signatures of the metacarbonates, and by interlayered detrital sedimentary rocks with cross-lamination and storm-wave generated breccias. The ISB stromatolites predate by 220 Myr the previous most convincing and generally accepted multidisciplinary evidence for oldest life remains in the 3,480-Myr-old Dresser Formation of the Pilbara Craton, Australia4, 5. The presence of the ISB stromatolites demonstrates the establishment of shallow marine carbonate production with biotic CO2 sequestration by 3,700 million years ago (Ma), near the start of Earth’s sedimentary record. A sophistication of life by 3,700 Ma is in accord with genetic molecular clock studies placing life’s origin in the Hadean eon (>4,000 Ma)6.

See also here.

Newly discovered bacterial fossils may push back the date of the earliest direct evidence of life on Earth to 3.7 billion years ago, 220 million years older than the previous record. This is roughly four-fifths of the way back to the original formation of the planet, 4.6 billion years ago. If confirmed, this discovery would have tremendous significance for our understanding of the evolution of life in the universe: here.

Dinosaur-age haramiyids, mammals or reptiles?


This video from the USA says about itself:

High-tech analysis of proto-mammal fossil clarifies the mammalian family tree

16 November 2015

3D Reconstruction of the jaw of Haramiyavia, one of the earliest known proto-mammals, clarifies the debate over when mammals evolved. The study, published in the Proceedings of the National Academy of Sciences on Nov 16, 2015, confirms previous suggestions that mammal diversification occurred in the Jurassic around 175 million years ago—more than 30 million years after Haramiyavia and other forerunners to mammals diversified in the Triassic.

From the New York Times in the USA:

Jawbone in Rock May Clear Up a Mammal Family Mystery

By KENNETH CHANG

NOV. 16, 2015

With technologies like CT scans and 3-D printing, a team of scientists reported on Monday that it had solved a mystery about the family tree of mammals that started with a single tooth a century and a half ago.

The tooth, found in Germany in 1847, was tiny and distinctive in shape — not quite reptile, not quite mammal. More fossils of that kind were found around Europe, but always just single teeth. Scientists named this group of animals haramiyids — Arabic for “trickster.”

The teeth were embedded in rocks as old as 210 million years, an era in which ancestors of the first mammals were evolving.

“These were some of the most enigmatic fossils for years,” said Neil H. Shubin, a professor of organismal biology and anatomy at the University of Chicago. “People didn’t know what they were at all.”

In the late 1980s, Dr. Shubin, then a graduate student, was part of a team led by Farish Jenkins, a Harvard paleontologist, that searched for fossils in East Greenland. “You’re looking for tiny teeth in this vast Arctic landscape,” Dr. Shubin said. “The words ‘needle in a haystack’ seem very appropriate.”

The researchers found one particularly intriguing specimen, which they named Haramiyavia. “Avia” is Latin for “grandmother” — this was the grandmother of the trickster.

After a couple of years of meticulously clearing away much of the limestone surrounding the fossil, they reported on part of the Haramiyavia jawbone, revealing that the animal was indeed a proto-mammal.

What was unclear was whether Haramiyavia was a direct part of the family tree of mammals — that would push the emergence of mammals back to more than 200 million years ago — or an evolutionary branch that split off before common ancestors of mammals emerged, the view of paleontologists who believe that the first mammals evolved 170 million to 160 million years ago.

About two years ago, Dr. Shubin decided to re-examine the slab of Greenland limestone that enveloped the Haramiyavia fossil. “We knew that there were more bones in the rock,” he said.

Clearing away more limestone would jeopardize the fragile fossil. Instead, Dr. Shubin and his colleagues placed it in CT scanners and saw a mostly complete jawbone and many of the teeth.

“This kind of work used to be unimaginable,” said Zhe-Xi Luo, another University of Chicago paleontologist who joined Dr. Shubin on the new analysis.

Their conclusion: Haramiyavia, and thus all haramiyids, were not mammals, but belonged to a more ancestral side branch.

The crucial evidence they cite, reported Monday in the Proceedings of the National Academy of Sciences, is a trough in the lower jaw of Haramiyavia. In mammals, the trough is absent, because two bones connected to the trough migrated to the middle ear to form part of the three-bone hearing mechanism. (Birds and reptiles have only one bone in their middle ears.)

“This thing had a very primitive ear,” Dr. Shubin said. “That is the piece that is sort of the smoking gun.”

From the scans of the jaw and the teeth, the researchers created three-dimensional enlargements of the fossils, studying them like puzzle pieces to see how they fit together. Haramiyavia, a few inches long and rodentlike in appearance, ate plants by grinding leaves between broad teeth.

One argument that haramiyids were mammals was the similarity of the teeth to those of later animals known as multituberculates that were unquestionably mammals. But Dr. Shubin said the explanation instead was that the similar tooth characteristics evolved independently.

Timothy Rowe, a professor of geology at the University of Texas at Austin who was not involved in the new research, praised the work. “They really stepped out and squeezed every last bit of information that they could from these fossils,” he said. “What a relief after all these years to see a very compelling case made for exactly where haramiyids fit on the family tree.”

Dr. Rowe said there was no longer evidence that the earliest divergence of mammals occurred during the Triassic Period more than 200 million years ago. “The oldest date that’s based on real evidence is 30 or 40 million years younger than that,” he said. “It helps more accurately calibrate the mammalian tree of life.”

Not everyone agrees. “It’s a very great work, but I don’t think I’m totally convinced that is the case,” said Jin Meng, the curator of fossil mammals at the American Museum of Natural History in New York.

Dr. Meng is a member of a team that in the last couple of years has described more recent species of haramiyids that lived in China about 160 million years ago. The well-preserved Chinese fossils, nearly complete, possessed the characteristics of true mammals, Dr. Meng and his colleagues said.

The mammalian characteristics include the absence of a jawbone trough, Dr. Meng said in an interview. “If we accept the conclusion of this study, many of those mammalian structures must have evolved independently,” he said. “I still think the other hypotheses remain alive.”

Studying sanderlings in Greenland, videos


This is a series of ten videos about studying sanderlings in Greenland, by Dutch biologists Jeroen Reneerkens and Stefan Sand, doing research about sanderlings in the Zackenberg area in north-east Greenland in 2012.

A sanderling’s life


Sanderling G3BGGW on Texel, 31 December 2014 (photo Micheal Hermes)

Translated from Ecomare museum on Texel island in the Netherlands:

The life of G3BGGW – 12 February 2015

No, not a character from Star Wars. G3BGGW is a sanderling which was ringed in Iceland in May 2013. He was found dead on February 1, 2015 on Texel. What makes this bird so special is that he was not only seen several times in the past two years, but he was even seen alive a day before his death. So, the day of his death is very accurately known, something bird researcher Jeroen Reneerkens has experienced only a few times. Such small birds are almost never found when they die, let alone so quickly.

What’s in a name?

Thanks to his rings this sanderling was recognizable. When he came in sight of the telescopes of various bird watchers, viewers have noted the series of rings and passed the information on to the ring station. The letters in his name are about the colours: G = green, B = blue, W = white; the numeral 3 indicates that one of the rings is a flag, in this case a green flag, this was on “position 3”: above the rings on the left leg. Bird rings are read from left to right and from top to bottom.

Winter beach guest

Sanderlings are found on Dutch beaches outside the breeding season, so from late July to late May. The largest numbers you see on beaches in the winter months. They breed in the far north. … Those little birds that fast run back and forth with the surf – that are sanderlings. It seems like they are trying to go as close as possible to the water without making their feet wet. But actually they are looking for worms that appear quickly from the sand when the seawater flows over them. In the water there is plankton on which the worms feed. The birds try to catch the worms.

Lifespan

In Iceland G3BGGW was ringed and weighed. He weighed 71 grams and had OK fat stores to fly even further towards Greenland to breed. In winter sanderlings slim to about 50-55 grams. Five months later, he was seen on Texel, north of beach post 12. Then he came back a year later on the island, on November 5, 2014 at beach post 9. Presumably he remained until his death in this environment. Two days before his death he was seen on the parking lot near the beach. That is very strange for such a beach bird. There it cannot find food. The birdwatcher thought that he did not look too healthy there. The next day the bird was seen again on the beach and the next day he lay dead along the road to this beach.

Research

Jeroen Reneerkens for years has been doing research into sanderlings. To do that, he has a large network of people in many countries who help with the rings and retrieval of this species. Except for Iceland also in Greenland, Scotland, England, the Netherlands, Portugal, Mauritania, Ghana and Namibia research teams are involved. There are 6,000 birds ringed and 61,000 observations noted. A chore, but it provides a lot of information on which the survival of sanderlings can be mapped accurately. Furthermore, the scientists discovered that while most sanderlings are worm eaters, they eat shellfish only in Ghana! They swallow them in their entirety and so have strong stomach muscles. The life of bird G3BGGW is not over. Jeroen will investigate this bird further. By viewing its organs and fat, he hopes to find out why the animal died: by disease, age, something else? Such a fresh dead bird is an unique opportunity!

Inuit of northern Greenland and global warming


This video says about itself:

Living with the Inugguit

In 2010, Dr Stephen Leonard embarked on a year-long trip to live with the Inugguit of north-west Greenland, the northernmost settled people on Earth. His aim was to record the language, stories and songs of these communities. The traditional life of the community and its future is potentially threatened by a number of factors, one of which is climate change. Dr Leonard lived as a member of those communities, travelled on hunts, and recorded and filmed as he went. Here he talks about some of his experiences and reflects on a year spent in the midst of a fading culture.

By Gwyn Griffiths in Britain:

Book review: The Polar North

Monday 17th November 2014

A new book on the Inugguit people, who are struggling to survive in the face of environmental catastrophe, is a warning to us all, says GWYN GRIFFITHS

The Polar North
by Stephen Pax Leonard
(Francis Boutle Publishers, £20)

THE POLAR North is a remarkable story of tiny Inugguit communities with a culture and a language spoken by less than 1,000 people struggling to survive in the hostile environment of west Greenland and in a world that is changing culturally and environmentally.

The book’s two main concerns are the effects of global warming and globalisation on a precarious way of life and it is no small feat of endurance that Stephen Pax Leonard was able to survive the harsh environment and be accepted by a close-knit, often claustrophobic, society for a whole year during his research.

The immediacy of the writing makes for a gripping narrative and although Leonard at times hints at depression in the dark period of the year as well as discomfort during that of 24-hour daylight, he does not dwell on it. What he has produced is a scrupulously honest but hugely sympathetic view of these communities.

The book has stark warnings, primarily of climate change. Since the early 1990s it has not been possible to travel by dog sledge to Canada because the Smith Sound is now partly open all year round.

In January 2011, the sun rose two days earlier than normal over Ilulissat and the best explanation for this is a shocking one. The ice cap is melting, lowering the horizon.

As the sea ice, fundamental to the Inugguit way of life, contracts so does the culture. The transmission of stories, through which vital survival information was transferred, is dying out and the young people of north-west Greenland have only a fraction of the knowledge of the old hunters.

Empty minds become glued to Danish children’s television and violent video games. Alcohol abuse and suicide are major social problems.

The passing of a language and culture of fewer than 1,000 speakers may be irrelevant to many but if the polar Inugguit are the canary in our cultural coal mine, then such a loss may have more relevance than we realise.

There is never any opposition to biodiversity but language activists, linguists and anthropologists are constantly being asked to defend linguistic and cultural diversity.

Fifty per cent of the world’s languages will not exist by the end of this century and we are on the road to the fastest rate of linguistic and cultural destruction in history, driven by the forces of globalisation and consumerism.

The book examines with fascinating detail the links between language and the environment, along with the subtleties and nuance of Inugguit communication.

An excellent introduction to the subject and, in providing a wider context of concern, an essential read.

Bluefin tuna in Greenland waters


This video is called Superfish Bluefin Tuna.

From the Technical University of Denmark:

Bluefin tuna found hunting for mackerel in East Greenland waters

Sep 05, 2014

On a warm summer day in August 2012, Greenlandic fishermen and biologists caught an unusual catch while conducting an exploratory fishery for mackerel.

Three large bluefin tuna, each weighing ca. 100 kg, were among the several tonnes of mackerel that were caught that summer. The presence of bluefin tuna in waters near Greenland is a very rare event, and there are no other scientific reports of its presence so far north as the Denmark Strait. The most recent report of its occurrence near Greenland was a stranding in 1900 in the southwesternmost tip of Greenland at Qaqortoq (formerly known as Julianehåb).

Bluefin tuna usually search for prey in areas where surface temperatures are warmer than 11 C. However, because temperatures in August 2012 in the Denmark Strait were so warm, and because one of its favorite prey species, mackerel, had already expanded its range into the region, it is likely that bluefin tuna has expanded or is presently expanding its habitat to more northerly regions,” explains professor Brian MacKenzie, who together with senior scientist Mark Payne, senior scientist Jesper Boje (both from DTU Aqua), senior scientist Jacob Højer (Danish Meteorological Institute) and Department Head Helle Siegstad (Greenland Nature Institute, GNI), has been investigating the reasons why bluefin tuna and its summer dining menu are on the way to more northerly regions than usual.

The investigation, which was conducted as part of the EU projects Euro-Basin and NACLIM at the Centers for Ocean Life and Macroecology, Evolution and Climate, has been published in the August 2014 issue of the peer-reviewed scientific journal Global Change Biology.

Disappearance from Danish waters

The reason why Brian MacKenzie and his colleagues initially became interested in these tuna bycatches was to document changes in its migration behaviour and distributional range, and how these are being influenced by climate change and the abundances of both bluefin tuna themselves and their prey.

“The scientific community does not have a solid understanding of the factors that affect the migrations and geographical distribution of bluefin tuna and many other migratory species, but new knowledge like this can potentially help explain the unsolved mystery of why bluefin tuna disappeared from waters near Denmark and in the Norwegian Sea during the 1960s, and especially when they might come back,” says Brian MacKenzie, noting that in addition to the appearance in Denmark Strait in 2012, Iceland and Norway have been allocated new fishing quotas (30 tonnes each) for the species in 2014.

“The new quota allocations are presumably because the species has begun to expand its northerly feeding areas farther north. If summer temperatures continue to increase during this century, and if both bluefin tuna and its prey species are managed in sustainable ways, then it is likely that bluefin tuna could become a regular summer visitor in east Greenland waters, at least as far north as the Denmark Strait,” states Brian MacKenzie.

One, two or many tuna

The Denmark Strait is normally a much colder area without warm-adapted species such as bluefin tuna. How many tuna were present in summer 2012 is unknown.

“The data we have available are too limited to estimate how many tuna came so far north, but because the species is a schooling species, with schools having ca. 10-100 individuals, and because the fishermen caught the three tuna in the same haul, it is likely there were many more present,” Brian MacKenzie said.

“We are planning further investigations to determine whether this new migration behaviour toward more northern waters could be the result of an increase in the total population of Bluefin tuna,” the DTU Aqua-professor stress.

“Regardless of whether the stock has increased or not, climate-related changes in distributions of commercial fish like these we have seen already for mackerel and herring will mean that international management authorities will need to develop new fishery and ecosystem management plans,” says co-author Helle Siegstad, Head of the Department for Fish and Shellfish, GNI.

“We have already seen during the past few years with the case of the expansion of mackerel and herring into waters near the Faroe Islands, Iceland, Norway and now Greenland how complicated the discussions between jurisdictions can become. It will be important in future that we can provide authorities with a solid scientific and data basis, on for example bluefin tuna, when they are making new fishery management decisions,” says Brian MacKenzie.

The study, which details in depth the data as well as discusses key questions relating to the migratory origins of the tuna caught in Greenland, will form part of a theme session topic at the ICES Annual Science Conference which kicks off on 15 September in the Spanish coastal city of A Coruña.

Huge pirate tuna fishing operation exposed in Pacific, says Greenpeace. A Taiwanese longline vessel caught with 75kg of shark fins near Papua New Guinea was only the ‘tip of the iceberg’ of operations driving a decline in tuna: here.

The United States last week gave Pacific Island nations notice that it plans to withdraw from the 27-year-old South Pacific Tuna Treaty, its most important commercial, aid and trade pact within the region. Washington had agreed to pay $US89 million for its 2016 fishing rights and then reneged on the deal. Unless it is renegotiated, the treaty will expire in 12 months, with devastating economic and social consequences for jobs and livelihoods, as well as government revenues, in many small Pacific states: here.