Mapping icebergs in Greenland


This video from the USA says about itself:

18 April 2018

How is mapping an iceberg similar to mapping an asteroid? They are actually much the same kind of a mission: they both involve using an autonomous vehicle in an extreme environment to map and explore a remote moving object.

Taking on the task of mapping icebergs, engineers at the Monterey Bay Aquarium Research Institute developed the iceberg autonomous underwater vehicle (AUV). During an expedition to Greenland in 2017, the research team successfully tested new control technologies that would allow the vehicle to safely travel parallel to complex vertical terrain (i.e., an iceberg). To do this the engineers outfitted the AUV with obstacle-avoidance sonars, aligned in the horizontal plane, to make sure the vehicle didn’t collide with anything. The vehicle also had a second sonar on it, aligned in the vertical plane, looking out the left side of the vehicle. This vertical sonar collected mapping data revealing what the target surface looked like.

The team ran several successful repeat missions on three different icebergs.

Video producer: Nancy Barr
Interview videographer: Todd Walsh
Video editor: Kyra Schlining
Music: http://taketones.com/track/digital-love (License N: TT000270144)
Illustration: Kelly Lance

For more information, see the MBARI 2017 Annual Report.

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Cambrian fossils discovery in Greenland


This video says about itself:

26 March 2014

More than 500 million years ago in the Cambrian period there was an explosion of animal life. The top predators were from a group called the Anomalocarids, the largest animals of their day. But now, a new fossil suggests that not all the Anomalocarids were the fearsome killing machines scientists once thought. At least one, it seems, evolved into a gentle giant.

From Uppsala University in Sweden:

Treasure trove of highly detailed fossils uncovered

December 19, 2017

A team of researchers from Uppsala University have uncovered a hidden diversity of microscopic animal fossils from over half a billion years ago lurking in rocks from the northern tip of Greenland.

The ‘Cambrian explosion‘ of animal diversity beginning ~541 million years ago is a defining episode in the history of life. This was a time when the seas first teemed with animal life, and the first recognisably ‘modern’ ecosystems began to take shape.

Current accounts of this explosion in animal diversity rely heavily on records from fossilised shells and other hard parts, since these structures are the most likely to survive as fossils.

However, since most marine animals are ‘soft-bodied’ this represents only a small fraction of the total diversity.

Rare sites of exceptional fossilisation, like the world-famous Burgess Shale, have revolutionised palaeontologists understanding of ‘soft-bodied’ Cambrian life. Because of the special conditions of fossilisation at these localities, organisms that did not produce hard mineralized shells or skeletons are also preserved. Such sites offer a rare glimpse into the true diversity of these ancient seas, which were filled with a dazzling array of soft and squishy predatory worms and arthropods (the group containing modern crustaceans and insects).

One of the oldest of these truly exceptional fossil bonanzas is the Sirius Passet site in the far north of Greenland. Unfortunately, during their long history, the rocks at Sirius Passet have been heated up and baked to high temperatures as the northern margin of Greenland smashed into various tectonic plates and buried these rocks deep beneath the surface.

All this heating has boiled away the delicate organic remains that once formed the fossils of soft bodied animals at Sirius Passet, leaving only faint impressions of their remains.

Not far to the south of Sirius Passet, the rocks have escaped the worst effects of this heating. A team of palaeontologists from Uppsala (Ben Slater, Sebastian Willman, Graham Budd and John Peel) used a low-manipulation acid extraction procedure to dissolve some of these less intensively cooked mudrocks. To their astonishment, this simple preparation technique revealed a wealth of previously unknown microscopic animal fossils preserved in spectacular detail.

Most of the fossils were less than a millimetre long and had to be studied under the microscope. Fossils at the nearby Sirius Passet site typically preserve much larger animals, so the new finds fill an important gap in our knowledge of the small-scale animals that probably made up the majority of these ecosystems. Among the discoveries were the tiny spines and teeth of priapulid worms — small hook shaped structures that allowed these worms to efficiently burrow through the sediments and capture prey. Other finds included the tough outer cuticles and defensive spines of various arthropods, and perhaps most surprisingly, microscopic fragments of the oldest known pterobranch hemichordates — an obscure group of tube-dwelling filter feeders that are distant relatives of the vertebrates. This group became very diverse after the Cambrian Period and are among some of the most commonly found fossils in rocks from younger deposits, but were entirely unknown from the early Cambrian. This new source of fossils will also help palaeontologists to better understand the famously difficult to interpret fossils at the nearby Sirius Passet site, where the flattened animal fossils are usually complete, but missing crucial microscopic details.

‘The sheer abundance of these miniature animal fossils means that we have only begun to scratch the surface of this overlooked resource, but it is already clear that this discovery will help to reshape our view of the non-shelly animals that crawled and swam among the early Cambrian seas more than half a billion years ago,’ says Sebastian Willman, researcher at the Department of Earth Sciences, Uppsala University.

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.

Animals emerged from the water and clamored onto land more than 300 million years ago, but paleontologists are looking for even more details about the transition. A healed broken bone that later fossilized is offering some new and unexpected clues. A new fossil from Australia pushes back the origin of tetrapods, or four-limbed animals, more than two million years. The creature, Ossinodus, lived during the Devonian Period 333 million years ago in what would have been temperate forests: here.

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.

Coastal waters were an oxygen oasis 2.3 billion years ago. Despite being ripe for complex life, it took another 1.5 billion years for oxygen-hungry animals to evolve: here.

The breath of oxygen that enabled the emergence of complex life kicked off around 100 million years earlier than previously thought, new dating suggests. Previous studies pegged the first appearance of relatively abundant oxygen in Earth’s atmosphere, known as the Great Oxidation Event, or GOE, at a little over 2.3 billion years ago. New dating of ancient volcanic outpourings, however, suggests that oxygen levels began a wobbly upsurge between 2.460 billion and 2.426 billion years ago, researchers report the week of February 6 in Proceedings of the National Academy of Sciences: here.

Life on Earth could be nearly four billion years old, suggests new fossil discovery. The Earth was an extremely hostile place at the time as it was still being bombarded by asteroids: 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!