Amazing New 3D Images of Shark Intestines Show They Function Like Nikola Tesla’s Valve
Amazing New 3D Images of Shark Intestines Show They Function Like Nikola Tesla’s Valve
Pacific Spiny Dogfish Spiral Intestine

A CT scan image of the spiral intestine of a Pacific spiny dogfish shark (Squalus suckleyi). The beginning of the intestine is on the left, and the end is on the right. Credit: Samantha Leigh/California State University Dominguez Hills

Contrary to what popular media portrays, we actually don’t know much about what sharks eat. Even less is known about how they digest their food, and the role they play in the larger ocean ecosystem.

For more than a century, researchers have relied on flat sketches of sharks’ digestive systems to discern how they function — and how what they eat and excrete impacts other species in the ocean. Now, researchers have produced a series of high-resolution, 3D scans of intestines from nearly three dozen shark species that will advance the understanding of how sharks eat and digest their food.

Smooth Dogfish

Three smooth dogfish sharks (Mustelus canis). Credit: Elizabeth Roberts/Wikimedia Commons

“It’s high time that some modern technology was used to look at these really amazing spiral intestines of sharks,” said lead author Samantha Leigh, assistant professor at California State University Dominguez Hills. “We developed a new method to digitally scan these tissues and now can look at the soft tissues in such great detail without having to slice into them.”

The research team from California State University Dominguez Hills, the University of Washington, and University of California, Irvine, published its findings July 21 in the journal Proceedings of the Royal Society B.

CT Scan Dogfish Shark Spiral Intestine

A CT scan image of a dogfish shark spiral intestine, shown from the top looking down. Credit: Samantha Leigh/California State University Dominguez Hills

The researchers primarily used a computerized tomography (CT) scanner at the UW’s Friday Harbor Laboratories to create 3D images of shark intestines, which came from specimens preserved at the Natural History Museum of Los Angeles. The machine works like a standard CT scanner used in hospitals: A series of X-ray images is taken from different angles, then combined using computer processing to create three-dimensional images. This allows researchers to see the complexities of a shark intestine without having to dissect or disturb it.

Pacific Spiny Dogfish

A live Pacific spiny dogfish shark (Squalus suckleyi). Credit: Samantha Leigh/California State University Dominguez Hills

“CT scanning is one of the only ways to understand the shape of shark intestines in three dimensions,” said co-author Adam Summers, a professor based at UW Friday Harbor Labs who has led a worldwide effort to scan the skeletons of fishes and other vertebrate animals. “Intestines are so complex — with so many overlapping layers, that dissection destroys the context and connectivity of the tissue. It would be like trying to understand what was reported in a newspaper by taking scissors to a rolled-up copy. The story just won’t hang together.”

Smooth Dogfish Spiral Intestine

A CT scan image of a smooth dogfish shark (Mustelus canis) spiral intestine, shown
from the top looking down. Credit: Samantha Leigh/California State University Dominguez Hills

From their scans, the researchers discovered several new aspects about how shark intestines function. It appears these spiral-shaped organs slow the movement of food and direct it downward through the gut, relying on gravity in addition to peristalsis, the rhythmic contraction of the gut’s smooth muscle. Its function resembles the one-way valve designed by Nikola Tesla more than a century ago that allows fluid to flow in one direction, without backflow or assistance from any moving parts.

This finding could shed new light on how sharks eat and process their food. Most sharks usually go days or even weeks between eating large meals, so they rely on being able to hold food in their system and absorb as many nutrients as possible, Leigh explained. The slowed movement of food through their gut caused by the spiral intestine probably allows sharks to retain their food longer, and they also use less energy processing that food.

This video shows the 3D image of a Pacific spiny dogfish (Squalus suckleyi) spiral intestine. Credit: Samantha Leigh/California State University Dominguez Hills

Because sharks are top predators in the ocean and also eat a lot of different things — invertebrates, fish, mammals and even seagrass — they naturally control the biodiversity of many species, the researchers said. Knowing how sharks process what they eat, and how they excrete waste, is important for understanding the larger ecosystem.

“The vast majority of shark species, and the majority of their physiology, are completely unknown. Every single natural history observation, internal visualization and anatomical investigation shows us things we could not have guessed at,” Summers said. “We need to look harder at sharks and, in particular, we need to look harder at parts other than the jaws, and the species that don’t interact with people.”

This video shows the soft tissue of a Pacific spiny dogfish (Squalus suckleyi) spiral intestine, rotated and viewed from different angles. Credit: Samantha Leigh/California State University Dominguez Hills

The authors plan to use a 3D printer to create models of several different shark intestines to test how materials move through the structures in real time. They also hope to collaborate with engineers to use shark intestines as inspiration for industrial applications such as wastewater treatment or filtering microplastics out of the water column.

Reference: 20 July 2021, Proceedings of the Royal Society B.
DOI: 10.1098/rspb.2021.1359

Other co-authors on the paper are Donovan German of University of California, Irvine, and Sarah Hoffmann of Applied Biological Services.

This research was funded by Friday Harbor Laboratories, the UC Irvine OCEANS Graduate Research Fellowship, the Newkirk Center Graduate Research Fellowship, the National Science Foundation Graduate Research Fellowship Program and UC Irvine.

Mission to Venus: Europe’s large-scale return to space
Mission to Venus: Europe’s large-scale return to space

The European Space Agency has announced huge plans for the next three decades

The last few years have really looked exciting when it comes to space exploration. Only in 2021 did the United States and China land their spacecraft on Mars, where they are actively conducting missions.

Even the United Arab Emirates became the first Arab state to send a mission to the Red Planet and even make large-scale plans to build a Martian city.

As for the moon, NASA plans to send a man there again soon, while Russia and China want to build a whole habitable base together.

For their part, private companies are also showing increasing interest in space and are in themselves a competition reminiscent of that between the Soviet Union and the United States during the Cold War. Elon Musk’s SpaceX, Jeff Bezos’ Blue Origin and Richard Branson’s Virgin Galactic are building their own spaceships, and Bezos himself plans to fly among the stars next month.

Two weeks after Bezos leaves Amazon, he will fly aboard his own rocket.

And while America and Asia seem to be making more and more progress in space exploration, Europe somehow seems to be lagging behind. The latest large-scale missions of the European Space Agency (ESA) are the Venus Express, which ended in 2014, and the Mars Express, which is expected to be completed by the end of next year.

However, this will soon change, as ESA recently announced large-scale plans for the next three decades until 2050.

It is a multi-component Voyage 2050 strategy, “and its first missions are expected to launch at the beginning of the next decade. Most of them will be of the so-called L-Class, which means that they are large-scale and high-priority.”

“The plan is the result of the enormous efforts of the scientific community and the teams of our committee,” Fabio Favata, head of ESA’s Strategy, Planning and Coordination Office, said in an official statement. “Voyage 2050 has launched and will maintain Europe’s place in the forefront of space science for decades to come.”

The last missions of the current program until 2025 “Cosmic Vision” are currently in a different stage of development. The Cosmic Orbiter solar satellite has already been sent into space, while other special ARIEL, Euclid and Plato telescopes will be launched by the end of the decade.

Voyage 2050’s main focus will be on three areas: studying the giant moons in the solar system, observing exoplanets near our galaxy, and studying the evolution of the first structures in the early universe.

This will include studying the moons of Jupiter, Neptune and Saturn. Some of them are thought to have subterranean oceans, and hence the possibility of life.

ESA plans to return to Venus and launch the EnVision mission, which is worth 610 million euros, in 2031.

Compared to Mars, Venus is much less frequently visited, and so far only European, Russian, Japanese and American missions have reached it. The planet will increasingly attract our attention due to the observed climate change of Earth-like exoplanets.

Scientists will try to find the answer to the question why the atmosphere of Venus is so poisonous at the moment, provided that it once had quite similar characteristics to those of our planet. Once upon a time there was even water, but over time it disappears, carbon dioxide slowly begins to suffocate the atmosphere, and the greenhouse effect of the planet turns it into a real oven.

So far, more than 20 missions have been sent there, and thanks to them we know that the air of Venus is not exactly air. It consists of 97% carbon dioxide, which is so dense that it is about 100 times thicker than the Earth’s atmosphere. It also has a temperature of 462 degrees Celsius.

All this makes sending devices there a real challenge, because the atmosphere itself literally eats away at any material known to man.

Recently, the Venus Express finds evidence that Venus once had oceans and volcanoes. EnVision’s job will be to confirm this data and check for active volcanoes. as the available technology will allow a significantly deeper look at the composition of the local atmosphere and will also make it possible to look for possible traces of the presence of hot lava.

The latter can be done using a special radar provided by NASA. In fact, EnVision will follow two US missions that will depart for Venus a little earlier. VERITAS will make a detailed topography, while DAVINCI + will go deep into the planetary atmosphere and reach the surface itself.

Together, the three missions will complement each other and provide many answers for scientists about the different destinies of Venus and Earth.

And there will also be an opportunity to talk again about the European Space Agency as a leading factor in space research.

Le Figaro:The Struggle for Space – Part of the New Cold War
Le Figaro:The Struggle for Space – Part of the New Cold War

Space exploration has become relevant again, “got a second wind”, writes Le Figaro journalist Nicolas Bavere. The United States expects to send a man to the moon before the end of the decade and then prepare for flights to Mars. China, for its part, is developing at a tremendous rate in space: in 2019, it sent a ship to the far side of the moon, and recently its spacecraft landed on Mars. And China has ambitions to send its astronauts to Earth’s natural satellite by 2030. “The renaissance of space is inseparable from the new Cold War, in which the United States and China oppose each other,” the author wrote. During the bipolar system, space, along with nuclear weapons, was at the epicenter of hostilities between the United States and the Soviet Union. And it is space that will play a decisive role in the outcome of the confrontation between Washington and Beijing, the author of the article believes.

It determines the effectiveness of modern weapons. So, although international treaties prohibit the deployment of weapons of mass destruction in outer space, militarization is still taking place there. All major nations already have commands in the armed forces that deal with space.

Among other things, space is becoming the most important infrastructure for the digital economy and plays a crucial role in competition between countries and continents. “Space in the 21st century will become what the seas were – in the 19th century: whoever controls it controls the earth,” the author writes. The current phase of space exploration differs from the previous one in three respects.

First, space shuttles and the small size of satellites allow them to be concentrated and used for dual purposes.

Second, space has become a market and emerged from US monopoly. Although it is still under party control in China, private entrepreneurs have entered the United States.

Third, according to the author of the article, now the United States and China dominate in space, while Russia and Europe are receding into the background. And if Russia is trying to cooperate with China, Europe is content with second-rate programs. The European model of development is proving to be too complex and bureaucratic, outdated. It suffers from chronic underfunding and growing divisions between France and Germany. “Space is one of the key aspects of the strategic autonomy of France and Europe, both technologically, economically and militarily,” concluded the author of the article in Le Figaro.