How did life survive 'Snowball Earth'? In ponds, study suggests.
Earth hasn't always been a hospitable place to live. During several ice ages, the planet's surface was almost completely frozen over, creating what has been dubbed "Snowball Earth."
Liquid water appears to be the most important ingredient for life on any planet, raising the question: how did anything survive such frosty, brutal times?
A group of scientists said Thursday that they had found an astonishing diversity of microorganisms in tiny pools of melted ice in Antarctica, suggesting that life could have ridden out Snowball Earth in similar ponds.
During the Cryogenian Period between 635 and 720 million years ago, the average global temperature did not rise above minus 50 degrees Celsius. The climate near the equator at the time resembled modern-day Antarctica.
Yet even in such extreme conditions, life found a way to keep evolving.
Fatima Husain, the lead author of a new study published in Nature Communications, said there was evidence of complex life forms "before and after the Cryogenian in the fossil record."
"There are multiple hypotheses regarding possible places life may have persisted," said Husain, a graduate student at the Massachusetts Institute of Technology.
Perhaps it found shelter in patches of open ocean, or in deep-sea hydrothermal vents, or under vast sheets of ice.
The tiny melted ice pools that dotted the equator were another proposed refuge.
These ponds could have been oases for eukaryotes, complex organisms that eventually evolved into multicellular life forms that would rise to dominate Earth, including humans.
Melted ice ponds still exist today in Antarctica, at the edges of ice sheets.
In 2018, members of a New Zealand research team visited the McMurdo ice shelf in east Antarctica, home to several such pools, which are only a few meters wide and less a meter deep.
The bottom of the ponds are lined with a mat of microbes that have accumulated over the years to form slimy layers.
"These mats can be a few centimeters thick, colorful, and they can be very clearly layered," Husain said.
They are made up of single-celled organisms called cyanobacteria that are known to be able to survive extreme conditions.
But the researchers also found signs indicating there were eukaryotes such as algae or microscopic animals.
This suggests there was surprising diversity in the ponds, which appears to have been influenced by the amount of salt each contained.
"No two ponds were alike," Husain said. "We found diverse assemblages of eukaryotes from all the major groups in all the ponds studied."
"They demonstrate that these unique environments are capable of sheltering diverse assemblages of life, even in close proximity," she added.
This could have implications in the search for extraterrestrial life.
"Studies of life within these special environments on Earth can help inform our understanding of potential habitable environments on icy worlds, including icy moons in our Solar System," Husain said.
Saturn's moon Enceladus and Jupiter's Europa are covered in ice, but scientists increasingly suspect they could be home to simple forms of life, and several space missions have been launched to find out more about them.
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Japan Times
21-06-2025
- Japan Times
How did life survive 'Snowball Earth'? In ponds, study suggests.
Earth hasn't always been a hospitable place to live. During several ice ages, the planet's surface was almost completely frozen over, creating what has been dubbed "Snowball Earth." Liquid water appears to be the most important ingredient for life on any planet, raising the question: how did anything survive such frosty, brutal times? A group of scientists said Thursday that they had found an astonishing diversity of microorganisms in tiny pools of melted ice in Antarctica, suggesting that life could have ridden out Snowball Earth in similar ponds. During the Cryogenian Period between 635 and 720 million years ago, the average global temperature did not rise above minus 50 degrees Celsius. The climate near the equator at the time resembled modern-day Antarctica. Yet even in such extreme conditions, life found a way to keep evolving. Fatima Husain, the lead author of a new study published in Nature Communications, said there was evidence of complex life forms "before and after the Cryogenian in the fossil record." "There are multiple hypotheses regarding possible places life may have persisted," said Husain, a graduate student at the Massachusetts Institute of Technology. Perhaps it found shelter in patches of open ocean, or in deep-sea hydrothermal vents, or under vast sheets of ice. The tiny melted ice pools that dotted the equator were another proposed refuge. These ponds could have been oases for eukaryotes, complex organisms that eventually evolved into multicellular life forms that would rise to dominate Earth, including humans. Melted ice ponds still exist today in Antarctica, at the edges of ice sheets. In 2018, members of a New Zealand research team visited the McMurdo ice shelf in east Antarctica, home to several such pools, which are only a few meters wide and less a meter deep. The bottom of the ponds are lined with a mat of microbes that have accumulated over the years to form slimy layers. "These mats can be a few centimeters thick, colorful, and they can be very clearly layered," Husain said. They are made up of single-celled organisms called cyanobacteria that are known to be able to survive extreme conditions. But the researchers also found signs indicating there were eukaryotes such as algae or microscopic animals. This suggests there was surprising diversity in the ponds, which appears to have been influenced by the amount of salt each contained. "No two ponds were alike," Husain said. "We found diverse assemblages of eukaryotes from all the major groups in all the ponds studied." "They demonstrate that these unique environments are capable of sheltering diverse assemblages of life, even in close proximity," she added. This could have implications in the search for extraterrestrial life. "Studies of life within these special environments on Earth can help inform our understanding of potential habitable environments on icy worlds, including icy moons in our Solar System," Husain said. Saturn's moon Enceladus and Jupiter's Europa are covered in ice, but scientists increasingly suspect they could be home to simple forms of life, and several space missions have been launched to find out more about them.
The Mainichi
26-05-2025
- The Mainichi
New nasal COVID vaccine offers high immunity in animal tests: Tokyo researchers
TOKYO -- A new type of coronavirus vaccine administered nasally has proven effective when tested on animals, researchers at the University of Tokyo Pandemic Preparedness, Infection and Advanced Research Center (UTOPIA) have announced. The research team including UTOPIA Director Yoshihiro Kawaoka claim that in addition to preventing serious illness, the nasal vaccine is expected to prevent the spread of infection by inhibiting growth of the virus in the nose. Since the global outbreak of COVID-19, vaccines using messenger RNA (mRNA), which contains genetic information, have been developed and put into widespread use for inoculations. However, there has been demand for new types of vaccines that boost immunity in areas where infection occurs, such as the upper respiratory tract, and which inhibit the spread of the virus even if infection occurs. The team created viruses using genetic information from which the parts of the coronavirus' genes needed to assemble viral particles were removed. Inside human and other cells, these engineered viruses create proteins needed for acquiring immunity. Because they cannot build the viral structure or core components themselves, there is no risk of them multiplying and spreading. When a vaccine with the artificial virus was administered nasally to mice, immunity was achieved on the mucous membranes of their nasal cavity and lungs. The new type reportedly achieves particularly wide immunity coverage in the lungs when compared to mRNA vaccines. Next, when a group of eight hamsters treated with the nasal vaccine was infected with the delta variant of the coronavirus and omicron's XBB subvariant, neither of these virus variants propagated in the lungs. The nasal cavities of around half of the hamsters were reportedly free of viral growth on the third day after infection, and even in the other half, the amount of growth was significantly suppressed, disappearing by the sixth day. Kawaoka commented, "The nasal vaccine is effective for respiratory tract infections and is thought to be effective in preventing the spread of infection. Unlike mRNA vaccines, it has the advantage of providing immunity similar to that acquired through actual viral infection." The results were published in the U.K. science journal Nature Communications.
Yomiuri Shimbun
03-05-2025
- Yomiuri Shimbun
Comet-like Planet Observed Disintegrating near Its Star
Jose-Luis Olivares, MIT / Handout via Reuters The disintegrating exoplanet BD+05 4868 Ab orbits a sun-like star 140 light years away from Earth in this illustration released on April 22. WASHINGTON (Reuters) — Astronomers have spotted a small rocky planet that orbits perilously close to its host star disintegrating as its surface is vaporized by stellar heat, trailed by a comet-like tail of mineral dust up to about 9 million kilometers long. About 5,800 planets beyond our solar system, called exoplanets, have been discovered since the 1990s. Of those, only four have been observed disintegrating in orbit, as this one is. This planet is the closest to our solar system of the four, giving scientists a unique opportunity to learn about what happens to these doomed worlds. The researchers have observed the planet, named BD+05 4868 Ab, as it gradually crumbles into dust, shedding material roughly equal to the mass of Mount Everest with each orbit of its star. The tail of dust trailing the planet wraps halfway around the star. The planet is estimated as between the size of our solar system's smallest and innermost planet Mercury and Earth's moon. It is located about 140 light years away from Earth in the constellation Pegasus. Its host star, a type called an orange dwarf, is smaller, cooler and dimmer than the sun, with about 70% of the sun's mass and diameter and about 20% of its luminosity. The planet orbits this star every 30.5 hours at a distance about 20 times closer than Mercury is to the sun. The planet's surface temperature is estimated at close to about 1,600 C thanks to its close proximity to its star. As a result, the planet's surface has probably been turned to magma — molten rock. 'We expect the planet to disintegrate into dust within the next million years or so,' said Marc Hon, a postdoctoral researcher at the Massachusetts Institute of Technology's Kavli Institute for Astrophysics and Space Research and lead author of the study published on April 22 in the Astrophysical Journal Letters. 'This is catastrophically quick in cosmic timescales. The disintegration is a runaway process. As more material from the planet turns into dust, the disintegration process gets faster,' Hon said. Once in space, the vaporized material cools down to form mineral dust that streams away from the planet. 'We know the dust grains in the tail can have sizes between large soot particles and fine grains of sand,' Hon said. 'We don't know the mineral composition of the tail yet.' The researchers detected BD+05 4868 Ab using the 'transit method,' observing a dip in the host star's brightness when the planet passes in front of it, from the perspective of a viewer on Earth. It was found using NASA's Transiting Exoplanet Survey Satellite, or TESS, space telescope. How the planet came to have its current close-in orbit is unclear. 'The planet's orbit is not seen to be visibly decaying from the data. It is possible that the planet initially formed farther away, and had its original orbit altered under the influence of an external body, such that the planet was sent much closer to the star,' Hon said. This could have resulted from the gravitational influence of another planet or some other celestial object. The researchers plan further observations in the coming months using NASA's James Webb Space Telescope to study the composition of the material in the tail, which could give clues about the makeup of rocky exoplanets. The search for life in other solar systems focuses on rocky exoplanets orbiting stars in the 'habitable zone,' a distance where liquid water, a key ingredient for life, can exist on a planetary surface. 'The tail is expected to contain minerals evaporated from the surface or interior of the disintegrating planet. So, this could be the crust, mantle or even the planet's core. Learning about the interiors of planets is extremely challenging. Doing this even for planets within our solar system is difficult. But BD+05 4868 Ab will allow us to directly measure the mineral composition of a terrestrial planet outside our solar system,' Hon said. 'This is definitely an exceptional opportunity for exoplanet geology and to understand the diversity and potential habitability of rocky worlds beyond our solar system,' Hon said.
