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Fossil reveals burrowing lifestyle of tiny dino – Phys.org

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Microsaurs are a group of small, lizard-like animals that roamed the Earth more than a quarter billion years ago, well before proper dinosaurs made their appearance.

A finger-sized fossil from 308 million years ago unearthed in the United States gives tantalizing clues to the habits of tiny dinosaur-like creatures that may be the forerunners of reptiles, researchers revealed Wednesday.

The is a microsaur—small, lizard-like animals that roamed the Earth well before proper dinosaurs made their appearance.

The find sheds important light on the evolution of different animal groups, including amphibians and reptiles, scientists wrote in the journal Royal Society Open Science.

Microsaurs lived during the Carboniferous period, when the forebears of modern mammals and reptiles, called amniotes, first appeared.

“Many details of that transition aren’t well known,” study co-author Arjan Mann, a post-doctoral research fellow at the Smithsonian Institution, told AFP.

“Microsaurs have recently become important in understanding the origins of amniotes,” he said. “A lot of these microsaurs have been thought to be either ancestors of amphibians or ancestors of reptiles.”

Encased in a bog in what is today the central United States, the specimen’s serpent-like body measures about five centimeters (two inches).

The animals had four short, plump legs.

In deference to its tiny size, researchers dubbed the new species Joermungandr bolti after a giant sea serpent from Norse mythology who did battle with Thor.

In deference to its tiny size, researchers dubbed the new species Joermungandr bolti after a giant sea serpent from Norse mythol
In deference to its tiny size, researchers dubbed the new species Joermungandr bolti after a giant sea serpent from Norse mythology who did battle with Thor.

Scientists were astonished to discover the fossil also contained the animal’s skin.

“Areas of the skin had only been known from fragmentary fossils before,” said Mann.

“This microsaur is the whole shebang… that’s very rare for these fossils. It’s very rare for anything 300 million years old to have skin with it!”

Head-first burrower

Contrary to previous ideas about microsaurs, which had been classed as amphibians, Mann and his team discovered that Joermungandr had scales.

“Modern amphibians… are soft and slimy things, this was not a soft and slimy thing,” says Mann.

“This animal really had a -like look to it.”

Mann said the research suggests not only that microsaurs might be early relatives of reptiles, but also that the ability to burrow may have played a bigger role in the origin of amniotes than originally thought.

Astonishingly, the 300-million year old fossil also contained the animal's skin
Astonishingly, the 300-million year old fossil also contained the animal’s skin.

The researchers used a highly sensitive imaging technique called scanning electron microscopy (SEM) to get an up-close look at the nearly perfect fossil.

They discovered a pattern of ridges similar to those found on the scales of modern reptiles that dig into the ground.

Along with other features like a robust skull and elongated body, the scale shape led researchers to hypothesize that Joermungandr burrowed as well.

“It would probably have been a head-first burrower, using its head to smack itself into the soil,” said Mann.

“Its limbs were probably not very functional. It may have used them to stabilize itself as it was wobbling around. But its primary mode of movement would have been side winding like a snake.”

The SEM imaging technique is now being applied to many other ancient fossils, Mann said.

“We plan to do a lot of SEM and also 3D printing the scales at larger sizes,” he added. “And some biomechanics to see how they interacted with things like dirt and water.”


Explore further

A fossil discovery reveals the earliest relative of modern mammals


More information:
Joermungandr bolti, an exceptionally preserved ‘microsaur’ from Mazon Creek, Illinois, reveals patterns of integumentary evolution in Recumbirostra, Royal Society Open Science (2021). royalsocietypublishing.org/doi/10.1098/rsos.210319

© 2021 AFP

Citation:
Fossil reveals burrowing lifestyle of tiny dino (2021, July 21)
retrieved 21 July 2021
from https://phys.org/news/2021-07-fossil-reveals-burrowing-lifestyle-tiny.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
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Meteor Shower 2021: Why There Are Only A Few Precious Hours In 2021 When You Can Reliably See ‘Shooting Stars’ – Forbes

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Have you ever seen a “shooting star?” If you haven’t, you’ll no doubt have read articles imploring you to go outside and experience a “shower” of meteors. 

There’s no such thing as a “meteor shower.” 

Meteoroids don’t behave like that. “Shooting stars” are caused by Earth’s atmosphere colliding with clumps of dust left along its orbital path by a passing comet. They look like streaks and they last around a second, depending on the “shower” in question.

“Shooting stars” are sudden events that can happen anywhere in the night sky, but they’re sporadic. They rarely happen together. For instance, you might see one out of the corner of your eye and, five minutes later, see another one in a completely different part of the sky. Many of them you will miss. There are never two or three—or more—“raining down” at the same time, as composite photographs would suggest.

Besides, when you read that a “meteor shower” like the Lyrids, Orionids or Geminids could have “up to 150 shooting stars per hour,” what it really means that it might be possible to see that many (the so-called zenithal hourly rate or ZHR) in perfect conditions. That scenario is, in practice, impossible to achieve—you would need to be observing the entire night sky constantly, for many hours either side of the absolute “peak” of activity, and in super-dark skies. 

However, the biggest factor that determines what you’re likely to see—and one many meteor shower-promoters fail to point out—is the effect of Moon and moonlight.

If there’s a first quarter Moon or anything brighter, particularly a full Moon, in the sky during the peak night(s) of a meteor shower, you can forget seeing anything other than the very brightest of “shooting stars.” And they’re very rare. 

If the Moon is big and bright then, in effect, you’ll be observing from under a heavily light-polluted night sky even if you’ve gone to a dark sky destination. 

So which meteor showers are the ones to go for in 2021? There are going to be three meteor showers in 2021 that will occur under near-ideal conditions. 

The bad news?

The first (and by far the best) one isn’t until August 2021.

The good news?

It’s the Perseids, arguably the most famous and easiest meteor shower to observe in the northern hemisphere … largely because it occurs in the middle of summer when it’s easiest to be outdoors at night. 

The best three meteor showers in 2021, these will be best observed after midnight, with the exception of the Draconids, which can be observed right after dark. 

1. Perseid meteor shower 2021

When: Thursday/Friday, August 12/13, 2021

Moon phase: 23%-lit crescent Moon

ZHR: 110

2. Draconid meteor shower 2021

When: Friday/Saturday, October 8/9, 2021

Moon phase: 10%-lit crescent Moon

ZHR: 10

3. South Taurid meteor shower 2021

When: Thursday/Friday, November 4/5, 2021

Moon phase: 0.1%-lit crescent Moon

ZHR: 10

Wishing you clear skies and wide eyes.

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Lake Huron sinkhole surprise: The rise of oxygen on early Earth linked to changing planetary rotation rate – Phys.org

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A scuba diver observes the purple, white and green microbes covering rocks in Lake Huron’s Middle Island Sinkhole. Credit: Phil Hartmeyer, NOAA Thunder Bay National Marine Sanctuary.

The rise of oxygen levels early in Earth’s history paved the way for the spectacular diversity of animal life. But for decades, scientists have struggled to explain the factors that controlled this gradual and stepwise process, which unfolded over nearly 2 billion years.

Now an international research team is proposing that increasing on the early Earth—the spinning of the young planet gradually slowed over time, making the days longer—may have boosted the amount of oxygen released by photosynthetic cyanobacteria, thereby shaping the timing of Earth’s oxygenation.

Their conclusion was inspired by a study of present-day microbial communities growing under extreme conditions at the bottom of a submerged Lake Huron sinkhole, 80 feet below the water’s surface. The water in the Middle Island Sinkhole is rich in sulfur and low in oxygen, and the brightly colored bacteria that thrive there are considered good analogs for the single-celled organisms that formed mat-like colonies billions of years ago, carpeting both land and seafloor surfaces.

The researchers show that longer day length increases the amount of oxygen released by photosynthetic microbial mats. That finding, in turn, points to a previously unconsidered link between Earth’s oxygenation history and its . While the Earth now spins on its axis once every 24 hours, day length was possibly as brief as 6 hours during the planet’s infancy.

The team’s findings are scheduled for publication Aug. 2 in the journal Nature Geoscience.

Lead authors are Judith Klatt of the Max Planck Institute for Marine Microbiology and Arjun Chennu of the Leibniz Centre for Tropical Marine Research. Klatt is a former postdoctoral researcher in the lab of University of Michigan geomicrobiologist Gregory Dick, who is one of the study’s two corresponding authors. The other co-authors are from U-M and Grand Valley State University.

“An enduring question in the Earth sciences has been how did Earth’s atmosphere get its oxygen, and what factors controlled when this oxygenation took place,” Dick said from the deck of the R/V Storm, a 50-foot NOAA research vessel that carried a team of scientists and scuba divers on a sample-collection trip from the town of Alpena, Michigan, to the Middle Island Sinkhole, several miles offshore.

“Our research suggests that the rate at which the Earth is spinning—in other words, its day length—may have had an important effect on the pattern and timing of Earth’s oxygenation,” said Dick, a professor in the U-M Department of Earth and Environmental Sciences.

The researchers simulated the gradual slowing of Earth’s rotation rate and showed that longer days would have boosted the amount of oxygen released by early cyanobacterial mats in a manner that helps explain the planet’s two great oxygenation events.

[embedded content]

The project began when co-author Brian Arbic, a physical oceanographer in the U-M Department of Earth and Environmental Sciences, heard a public lecture about Klatt’s work and noted that day length changes could play a role, over geological time, in the photosynthesis story that Dick’s lab was developing.

Cyanobacteria get a bad rap these days because they are the main culprits behind the unsightly and toxic algal blooms that plague Lake Erie and other water bodies around the world.

But these microbes, formerly known as blue-green algae, have been around for billions of years and were the first organisms to figure out how to capture energy from sunlight and use it to produce organic compounds through photosynthesis—releasing oxygen as a byproduct.

Masses of these simple organisms living in primeval seas are credited with releasing oxygen that later allowed for the emergence of multicellular animals. The planet was slowly transformed from one with vanishingly small amounts of oxygen to present-day atmospheric levels of around 21%.

At the Middle Island Sinkhole in Lake Huron, purple oxygen-producing cyanobacteria compete with white sulfur-oxidizing bacteria that use sulfur, not sunlight, as their main energy source.

In a microbial dance repeated daily at the bottom of the Middle Island Sinkhole, filmy sheets of purple and white microbes jockey for position as the day progresses and as environmental conditions slowly shift. The white sulfur-eating bacteria physically cover the purple cyanobacteria in the morning and evening, blocking their access to sunlight and preventing them from carrying out oxygen-producing photosynthesis.

But when sunlight levels increase to a critical threshold, the sulfur-oxidizing bacteria migrate back down below the photosynthetic cyanobacteria, enabling them to start producing oxygen.

New theory: Earth's longer days kick-started oxygen growth
This June 19, 2019 photo provided by NOAA Thunder Bay National Marine Sanctuary shows purple microbial mats in the Middle Island Sinkhole in Lake Huron, Mich. Small hills and “fingers” like this one in the mats are caused by gases like methane and hydrogen sulfide bubbling up beneath them. Feel like days are just getting longer? They are and it’s a good thing because we wouldn’t have much to breathe if they weren’t, according to a new explanation for how Earth’s oxygen rich atmosphere may have developed because of Earth’s rotation slowing. Scientists provided evidence for this new hypothesis by lab testing gooey smelly purple bacteria from a deep sinkhole in Lake Huron. Credit: Phil Hartmeyer/NOAA Thunder Bay National Marine Sanctuary

The vertical migration of sulfur-oxidizing bacteria has been observed before. What’s new is that the authors of the Nature Geoscience study are the first to link these microbial movements, and the resultant rates of oxygen production, to changing day length throughout Earth’s history.

“Two groups of microbes in the Middle Island Sinkhole mats compete for the uppermost position, with sulfur-oxidizing bacteria sometimes shading the photosynthetically active cyanobacteria,” Klatt said while processing a core sample from Middle Island Sinkhole microbial mats in an Alpena laboratory. “It’s possible that a similar type of competition between microbes contributed to the delay in oxygen production on the early Earth.”

A key to understanding the proposed link between changing day length and Earth’s oxygenation is that longer days extend the afternoon high-light period, allowing photosynthetic cyanobacteria to crank out more oxygen.

“The idea is that with a shorter day length and shorter window for high-light conditions in the afternoon, those white sulfur-eating bacteria would be on top of the photosynthetic bacteria for larger portions of the day, limiting oxygen production,” Dick said as the boat rocked on choppy waters, moored a couple hundred yards from Middle Island.

The present-day Lake Huron microbes are believed to be good analogs for ancient organisms in part because the extreme environment at the bottom of the Middle Island Sinkhole likely resembles the harsh conditions that prevailed in the shallow seas of early Earth.

Lake Huron is underlain by 400-million-year-old limestone, dolomite and gypsum bedrock that formed from the saltwater seas that once covered the continent. Over time, the movement of groundwater dissolved some of that bedrock, forming caves and cracks that later collapsed to create both on-land and submerged sinkholes near Alpena.

Cold, oxygen-poor, sulfur-rich groundwater seeps into the bottom of the 300-foot-diameter Middle Island Sinkhole today, driving away most plants and animals but creating an ideal home for certain specialized microbes.

Dick’s team, in collaboration with co-author Bopaiah Biddanda of the Annis Water Resources Institute at Grand Valley State University, has been studying the microbial mats on the floor of Middle Island Sinkhole for several years, using a variety of techniques. With the help of scuba divers from NOAA’s Thunder Bay National Marine Sanctuary—which is best known for its shipwrecks but is also home to the Middle Island Sinkhole and several others like it—the researchers deployed instruments to the lake floor to study the chemistry and biology there.

They also brought mat samples to the lab to conduct experiments under controlled conditions.

Klatt hypothesized that the link between day length and oxygen release can be generalized to any given mat ecosystem, based on the physics of oxygen transport. She teamed up with Chennu to conduct detailed modeling studies to relate microbial mat processes to Earth-scale patterns over geological timescales.

The modeling studies revealed that day length does, in fact, shape oxygen release from the mats.

“Simply speaking, there is just less time for the oxygen to leave the mat in shorter days,” Klatt said.

This led the researchers to posit a possible link between longer day lengths and increasing atmospheric oxygen levels. The models show that this proposed mechanism might help explain the distinctive stepwise pattern of Earth’s oxygenation, as well as the persistence of low-oxygen periods through most of the planet’s history.

Throughout most of Earth’s history, atmospheric oxygen was only sparsely available and is believed to have increased in two broad steps. The Great Oxidation Event occurred about 2.4 billion years ago and has generally been credited to the earliest photosynthesizing cyanobacteria. Nearly 2 billion years later a second surge in , known as the Neoproterozoic Oxygenation Event, occurred.

Earth’s rotation rate has been slowly decreasing since the planet formed about 4.6 billion years ago due to the relentless tug of the moon’s gravity, which creates tidal friction.


Explore further

Researchers find oxygen spike coincided with ancient global extinction


More information:
Possible link between Earth’s rotation rate and oxygenation, Nature Geoscience (2021). DOI: 10.1038/s41561-021-00784-3 , www.nature.com/articles/s41561-021-00784-3

Citation:
Lake Huron sinkhole surprise: The rise of oxygen on early Earth linked to changing planetary rotation rate (2021, August 2)
retrieved 2 August 2021
from https://phys.org/news/2021-08-lake-huron-sinkhole-oxygen-early.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.

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Astronomers spot light behind a black hole for the first time, reaffirming Einstein's theory of general relativity – TechSpot

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Something to look forward to: An international team of astronomers have observed light from behind a black hole for the first time. Future observatories, like the Advanced Telescope for High Energy Astrophysics (Athena) should provider even higher resolution images with much shorter observation times.1

Led by Stanford University’s Dan Wilkins, the team focused on a black hole that is 10 million times as massive as our sun and located 1,800 million light years away in a galaxy called I Zwicky.

Armed with the European Space Agency’s XMM-Newton and NASA’s NuSTAR space telescopes, the astronomers observed bright flares of X-ray light coming from around the black hole. The X-ray flares echoed off of gas that was falling into the black hole, and as the flares were subsiding, the telescopes were remarkably able to pick up smaller flashes of X-rays that were different “colors.” These were the echoes bouncing off the gas behind the black hole.

“Any light that goes into that black hole doesn’t come out, so we shouldn’t be able to see anything that’s behind the black hole,” Wilkins said. “The reason we can see that is because that black hole is warping space, bending light and twisting magnetic fields around itself,” he added.

The black hole’s gravitational pull is responsible for the warping of space.

This is the first time that astronomers have directly observed light from behind a black hole, and it also matches Einstein’s theory of general relativity, yet again confirming his predictions.

The team’s findings were recently published in the scientific journal Nature.

Image credit Dan Wilkins

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