Photos released by NASA could prove that there’s life on Mars.
The photographs show what appears to be fungi on the Red Planet, therefore proving that Mars could in fact be home to some forms of life.
The theory comes from microbiologist Dr Xinli Wei from the Chinese Academy of Sciences, astrophysicist Dr Rudolph Schild from Harvard-Smithsonian and Dr. Rhawn Gabriel Joseph after studying NASA’s Curiosity rover images.
They’ve dubbed the odd-looking specimens as a type of mushroom, MailOnline reports.
Describing the appearance of the mushrooms as being like ‘puffballs’, the scientists wrote in the study:
Fungi thrive in radiation intense environments. Sequential photos document that fungus-like Martian specimens emerge from the soil and increase in size, including those resembling puffballs (Basidiomycota). After obliteration of spherical specimens by the rover wheels, new sphericals-some with stalks-appeared atop the crests of old tracks.
This fungi then changes and grows along with Mars’ seasons, and is believed to grow up to a staggering 300 metres in the spring, but will disappear by the time winter comes round.
Leading on from this, scientists believe that this ‘may represent massive colonies of black fungi, mould, lichens, algae, methanogens and sulfur reducing species’.
Comparative statistical analysis found that nine ‘spherical specimens’, believed to be the so-called puffballs, emerged from beneath the soil. They were also found to have moved closer together over time.
In regards to how this proves that there could be life on Mars, the trio went on to explain:
Although similarities in morphology are not proof of life, growth, movement, and changes in shape and location constitute behaviour and support the hypothesis there is life on Mars.
Upon the discovery of fungus on Mars, it hasn’t just opened up the possibility of life on the planet, it’s also opened the possibility of buildings there being made out of it.
Last year, NASA announced that it was exploring technologies that could see people’s future homes on the Red Planet being made of the organisms.
Lynn Rothschild, the principal investigator on NASA’s myco-architecture project said at the time, ‘Right now, traditional habitat designs for Mars are like a turtle — carrying our homes with us on our backs – a reliable plan, but with huge energy costs. Instead, we can harness mycelia to grow these habitats ourselves when we get there.’
A new analysis of data from the 1978 Pioneer Venus mission, by researchers at Cal Poly Pomona, finds evidence not only for phosphine, but also possible chemical disequilibrium in Venus’ atmosphere, an additional possible sign of biological activity.Sharing is caring!
In late 2020, scientists studying the atmosphere of Venus announced the surprising – and controversial – discovery of phosphine, a chemical that, on Earth, is produced primarily by living organisms. Jane Greaves at Cardiff University in Wales and her colleagues asked at the time: could the phosphine be a sign of microorganisms inhabiting Venus’ atmosphere? Maybe, other scientists said, but phosphine itself wouldn’t be proof of life, and subsequent studies questioned whether the phosphine was ever there at all. Then – in March, 2021 – a study from Rakesh Mogul of Cal Poly Pomona supported the original finding of phosphine and went further. It suggested other “biologically relevant chemicals” in Venus’ atmosphere that appear to be in a state of disequilibrium: another hallmark of life.
The new study focused on the re-analysis of data from the old Pioneer Venus mission, which sent four probes into Venus’ atmosphere in 1978, collecting data as they plunged toward the surface. This was the Pioneer Venus Multiprobe part of the mission, with three small probes and one larger one. The scientists analyzed data from the largest probe. The tantalizing peer-reviewed results were published in Geophysical Research Letters on March 10, 2021.
We re-examined archived data obtained by the Pioneer Venus Large Probe Neutral Mass Spectrometer. Our results reveal the presence of several minor chemical species in Venus’ clouds including phosphine, hydrogen sulfide, nitrous acid (nitrite), nitric acid (nitrate), hydrogen cyanide, and possibly ammonia.
The presence of these chemicals suggest that Venus’ clouds are not at equilibrium; thereby, illuminating the potential for [possibly life-related] chemistries yet to be discovered.
Mogul and his team found that the original analysis back in 1978 focused only on the most common chemicals that were expected to be found in Venus’ atmosphere. He told space journalist Nancy Atkinson in a March 25 article for The Planetary Society:
The focus on the minor and trace [chemical] species was minimal. That’s what we realized after looking at the archival data and the associated publications. We immediately found signals in data that other publications hadn’t discussed or mentioned. That was all we needed for motivation to keep going.
According to Mogul and his team, these chemicals could be evidence for redox disequilibria, processes suggestive of life. For example, on Earth, microbes take advantage of the redox disequilibrium found in natural environments like water to derive energy. Could something similar be happening in the atmosphere of Venus? Are parts of the atmosphere, at least, a potential habitable zone for microorganisms?
False-color view of Venus (to bring out details) from Japan’s Akatsuki orbiter. Image via JAXA/ ISAS/ Akatsuki Project Team/ Royal Astronomical Society/ Attribution: CC BY 4.0.
The temperate zone in Venus’ atmosphere where temperatures and pressures are more habitable for life. Image via Seager et al. (2020)/ Astronomy.
The data for this study come from the Large Probe Neutral Mass Spectrometer (LNMS), which was on the largest of the four probes that descended to Venus’ surface in 1978. The composition of the atmosphere was measured several times during descent. LNMS targeted gas molecules in the atmosphere that have a neutral charge. Phosphine would be one of those gases.
The Pioneer Venus data are important, especially since they were obtained in-situ, in the atmosphere itself, instead of remotely by Earth-based telescopes, as the other data last year had been.
The disequilibrium in Earth’s atmosphere is due to life, but whether the same is true for Venus is still unknown. This latest study supports that it could be, but more data are still needed, most likely from a return mission, to know for sure. Astronomers also say that this kind of disequilibrium could be used to search for evidence of life on exoplanets. Wouldn’t it be fascinating if that first evidence actually came from someplace much closer to home? From the linked paper in Science Advances (2018):
Chemical disequilibrium in planetary atmospheres has been proposed as a generalized method for detecting life on exoplanets through remote spectroscopy. Among solar system planets with substantial atmospheres, the modern Earth has the largest thermodynamic chemical disequilibrium due to the presence of life.
The new study was led by Rakesh Mogul at CalPolyPomona. Image via LinkedIn.
Today, the surface of Venus is horrendously uninhabitable, with temperatures of 840 degrees F (450 degrees C) – hot enough to melt lead – and crushing atmospheric pressure. But the middle layers of the atmosphere are temperate and Earth-like in temperature and pressure, although the clouds do contain abundant sulphuric acid. But there has been growing evidence that the planet used to be much more Earth-like earlier in its history, with rain, lakes and oceans. Less than a billion years ago however, something happened to cause a catastrophic greenhouse effect, where Venus transformed into the hellish world we see today.
Could there have been microscopic life of some kind, which then sought refuge in the clouds, away from the burning surface? Perhaps.
It will be very interesting to see what other follow-up studies say about this newest chapter in the phosphine on Venus enigma, and the possible disequilibrium. As Mogul said:
There are always mysteries to be solved and I think what we just showed that sometimes old data can reveal new stories. This is all a process, and moving forward is what science is all about.
Scientists think that Venus was once much more Earth-like, with rain, lakes and even oceans. Did it ever have surface life? Image via NASA.
Bottom line: A new analysis of data from the 1978 Pioneer Venus mission finds evidence not only for phosphine, but also possible chemical disequilibrium in Venus’ atmosphere, an additional possible sign of biological activity.
Lightning may have played a key role in the emergence of life on Earth.Nolan Caldwell/Getty Images
In 2016, a family in Illinois thought that a meteorite had hit their backyard. They called up the geology department at nearby Wheaton College to say that whatever struck their property had started a small fire and had left a weird rock embedded in the scorched dirt.
“Meteorites, contrary to popular belief, are cold when they hit the ground,” says Benjamin Hess, who was an undergraduate at the college but is now a graduate student at Yale University. “My professor readily figured out that that was probably a lightning strike.”
When lighting strikes sand, soil or stone, it immediately melts the materials into a glassy clump known as a “fulgurite,” or lightning rock. When geologists excavated the one in Illinois, they found something unexpected inside — an important ingredient for life that had long been thought to be delivered to early Earth by meteorites.
A report on the find, in the journal Nature Communications, suggests that this could have been a way for lightning to have played a key role in the emergence of life.Article continues after sponsor message
Most of the fulgurites that have been studied in the past were collected on beaches or deserts, says Hess, because “it’s really easy to see a glass structure sticking out of the sand.” One that is buried in the soil and potentially hidden by random debris or vegetation is harder to spot, although it might contain different minerals produced when the bolt hit something like clay.
When the researchers dug out the fulgurite in Illinois, they first saw glassy bits on its surface. Below that was a thick, tree-root-like structure extending down about a foot and a half. “It’s just entirely made of glass and has, like, burned soil on the outside of it,” says Hess, adding that the object looked like a foggy gray mass with a lot of air holes.
Hess and two colleagues at the University of Leeds analyzed the minerals inside and found one called schreibersite. “Which was very strange,” says Hess.
This reactive mineral contains phosphorus, an essential element for life. Phosphorus “really plays a key role in a lot of the basic cell structures,” says Hess. For example, it makes up the backbone of DNA.
Phosphorus was abundant in early Earth, but geologists know that it was mostly inaccessible because it was trapped inside nonreactive minerals that don’t dissolve easily in water. That led to a mystery: Where did all the phosphorus needed to make biological molecules come from?
One possibility is meteorites, which can contain reactive minerals like schreibersite. When the Earth was forming and for the first billion years or so afterward, the planet was pelted with numerous meteorites.
“So people thought, ‘Aha! It could actually be an extraterrestrial phosphorous source that provided the reactive phosphorous needed for life to form,’ ” says Hess.
But it occurred to the researchers that lighting offered an alternative source of phosphorus for the young Earth — and one that had certain advantages.
After all, meteorite strikes declined in number over time as the solar system got cleared out, and meteorite impacts can also be hugely destructive. “Lightning doesn’t destroy an entire 100-kilometer area when it strikes,” Hess points out.
The team did a kind of back-of-the-envelope calculation to see if lightning strikes really might have contributed a significant amount of usable phosphorus.
“There are a lot of things to consider,” says Hess, “like what was the dominant rock type that was being struck on early Earth? How much land might there have been? What was the atmosphere like? How much lightning would come from that atmosphere? How much phosphorus was in the rock type?”
Data from satellites and other monitors show that these days, there are over 500 million flashes of lightning a year and that about a quarter of them strike the ground.
Climate modeling suggests that when Earth formed, about 4.5 billion years ago, to when life first emerged, about 3.5 billion years ago, there could have been 1 billion to 5 billion lightning flashes every year.
“Assuming there was a fair amount of land, it’s upwards of a billion lightning strikes a year,” says Hess.
He and his colleagues believe that around the time life formed, the amount of usable phosphorus created through lighting strikes would be about the same as that provided by meteorites. “There’s a large uncertainty there, but basically we found that they are essentially similar,” says Hess.
This new idea about lightning is “pretty cool,” says Hilairy Hartnett, an astrobiologist at Arizona State University who thinks a lot about phosphorus and its role in the potential for life on other planets.
“All life on Earth requires phosphorus, from the tiniest virus to the largest organisms,” she notes.
She thinks this team made a lot of reasonable guesses about whether lightning was important for making reactive phosphorus, but it’s just hard to know and it’s clear that meteorites did deliver large amounts of the stuff.
Still, “the lightning strikes deliver more than they might have expected,” says Hartnett.
So even if meteorite phosphorus was the big deal on early Earth, she says, this means lightning strikes are now a way that planets around other stars might get usable phosphorus, even if they aren’t constantly smacked by meteorites.
“It’s really nice,” she says, “to be able to say there’s more than one path to generating phosphorous that could be available to a planet that might be able to develop life.”
Date:December 28, 2020Source:Scripps Research InstituteSummary:Chemists have made a discovery that supports a surprising new view of how life originated on our planet. They demonstrated that a simple compound called diamidophosphate (DAP), which was plausibly present on Earth before life arose, could have chemically knitted together tiny DNA building blocks called deoxynucleosides into strands of primordial DNA.Share: FULL STORY
Chemists at Scripps Research have made a discovery that supports a surprising new view of how life originated on our planet.
In a study published in the chemistry journal Angewandte Chemie, they demonstrated that a simple compound called diamidophosphate (DAP), which was plausibly present on Earth before life arose, could have chemically knitted together tiny DNA building blocks called deoxynucleosides into strands of primordial DNA.
The finding is the latest in a series of discoveries, over the past several years, pointing to the possibility that DNA and its close chemical cousin RNA arose together as products of similar chemical reactions, and that the first self-replicating molecules — the first life forms on Earth — were mixes of the two.
The discovery may also lead to new practical applications in chemistry and biology, but its main significance is that it addresses the age-old question of how life on Earth first arose. In particular, it paves the way for more extensive studies of how self-replicating DNA-RNA mixes could have evolved and spread on the primordial Earth and ultimately seeded the more mature biology of modern organisms.
“This finding is an important step toward the development of a detailed chemical model of how the first life forms originated on Earth,” says study senior author Ramanarayanan Krishnamurthy, PhD, associate professor of chemistry at Scripps Research.
The finding also nudges the field of origin-of-life chemistry away from the hypothesis that has dominated it in recent decades: The “RNA World” hypothesis posits that the first replicators were RNA-based, and that DNA arose only later as a product of RNA life forms.
Is RNA too sticky?
Krishnamurthy and others have doubted the RNA World hypothesis in part because RNA molecules may simply have been too “sticky” to serve as the first self-replicators.
A strand of RNA can attract other individual RNA building blocks, which stick to it to form a sort of mirror-image strand — each building block in the new strand binding to its complementary building block on the original, “template” strand. If the new strand can detach from the template strand, and, by the same process, start templating other new strands, then it has achieved the feat of self-replication that underlies life.
But while RNA strands may be good at templating complementary strands, they are not so good at separating from these strands. Modern organisms make enzymes that can force twinned strands of RNA — or DNA — to go their separate ways, thus enabling replication, but it is unclear how this could have been done in a world where enzymes didn’t yet exist.
A chimeric workaround
Krishnamurthy and colleagues have shown in recent studies that “chimeric” molecular strands that are part DNA and part RNA may have been able to get around this problem, because they can template complementary strands in a less-sticky way that permits them to separate relatively easily.
The chemists also have shown in widely cited papers in the past few years that the simple ribonucleoside and deoxynucleoside building blocks, of RNA and DNA respectively, could have arisen under very similar chemical conditions on the early Earth.
Moreover, in 2017 they reported that the organic compound DAP could have played the crucial role of modifying ribonucleosides and stringing them together into the first RNA strands. The new study shows that DAP under similar conditions could have done the same for DNA.
“We found, to our surprise, that using DAP to react with deoxynucleosides works better when the deoxynucleosides are not all the same but are instead mixes of different DNA ‘letters’ such as A and T, or G and C, like real DNA,” says first author Eddy Jiménez, PhD, a postdoctoral research associate in the Krishnamurthy lab.
“Now that we understand better how a primordial chemistry could have made the first RNAs and DNAs, we can start using it on mixes of ribonucleoside and deoxynucleoside building blocks to see what chimeric molecules are formed — and whether they can self-replicate and evolve,” Krishnamurthy says.
He notes that the work may also have broad practical applications. The artificial synthesis of DNA and RNA — for example in the “PCR” technique that underlies COVID-19 tests — amounts to a vast global business, but depends on enzymes that are relatively fragile and thus have many limitations. Robust, enzyme-free chemical methods for making DNA and RNA may end up being more attractive in many contexts, Krishnamurthy says.make a difference: sponsored opportunityhttps://action.publicgood.com/embed.html?partner_id=sciencedaily&utm_source=sciencedaily&title=Discovery%20boosts%20theory%20that%20life%20on%20Earth%20arose%20from%20RNA-DNA%20mix%3A%20Newly%20described%20chemical%20reaction%20could%20have%20assembled%20DNA%20building%20blocks%20before%20life%20forms%20and%20their%20enzymes%20existed&url=https%3A%2F%2Fwww.sciencedaily.com%2Freleases%2F2020%2F12%2F201228095428.htm&utm_content=https%3A%2F%2Fwww.sciencedaily.com%2Freleases%2F2020%2F12%2F201228095428.htm&widget_type=card&action=Default&is_flex=true&match_type=terms&content_id=13885177&cid_match_type=regex&tag=coronavirus%20~%20unsponsored%20first%20responders%20variant%20terms%20match&target_id=a5b62d04-991b-4b01-a285-9a499e519227&target_type=campaign&is_filter=true&url_id=25771184&parent_org=sciencedaily&target_name=Support%20%20First%20Responders%20and%20Health%20Care%20Workers%20During%20Coronavirus&is_sponsored=false&sponsor_name=
Ramanarayanan Krishnamurthy, Eddy I. Jiménez, Clémentine Gibard. Prebiotic Phosphorylation and Concomitant Oligomerization of Deoxynucleosides to form DNA. Angewandte Chemie International Edition, 2020; DOI: 10.1002/anie.202015910
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The theory of evolution shows that all of life stems from a single root and that we are related, more or less distantly, to every other living thing on Earth. Our closest ancestors, as Charles Darwin recognized, are to be found among the great apes. But beyond this, confusion over the branching pattern of the tree of life means that things become less clear.
We know that life evolved from a common universal ancestor that gave rise to bacteria, archaea (other types of single-celled microorganisms) and eukaryotes (including multi-cellular creatures such as plants and animals). But what did the first animals look like? The past ten years have seen a particularly heated debate over this question. Now our new study, published in Science Advances, has come up with an answer.
Sponge vs comb jelly
From the 19th century to about ten years ago, there was general agreement that our most distant relatives are sponges. Sponges are so different from most animals that they were originally classified as members of the algae. However, genes and other features of modern sponges, such as the fact that they produce sperm cells, show that they certainly are animals. Their distinctness and simplicity certainly fit with the idea that the sponges came first.
But over the past decade, this model has been challenged by a number of studies comparing DNA from different animals. The alternative candidates for our most distant animal relatives are the comb jellies: beautiful, transparent, globe-shaped animals named after the shimmering comb-rows of cilia they beat to propel themselves through the water.
Comb jellies are superficially similar to jellyfish and, like them, are to be found floating in the sea. Comb jellies are undoubtedly pretty distant from humans, but, unlike the sponges, they share with us advanced features such as nerve cells, muscles and a gut. If comb jellies really are our most distant relatives, it implies that the ancestor of all animals also possessed these common features. More extraordinarily, if the first animals had these important characters then we have to assume that sponges once had them but eventually lost them.
Tracing the evolutionary tree
To understand how species evolved, scientists often use phylogenetic trees, in which the tips of the branches represent species. The points where branches split represent a common ancestor. The below image shows an example of a phylogenetic tree in which the sponge splits off first, and one in which the comb jelly splits off first.
Both the sponges-first and comb jellies-first evolutionary trees have been supported by different studies of genes, and the dispute seems to have resulted in a transatlantic stalemate, with most Europeans preferring the traditional sponges-first and the North Americans generally preferring the novel comb jellies-first.
The argument boils down to a question of how best to analyze the copious genetic data we now have available. One possibility put forward by the sponges-first supporters is that the animal tree that put comb jellies first is the result of an error. The problem occurs when one of the groups being studied has evolved much faster than the others. Fast evolving groups often look like they have been around for a long time. The comb jellies are one such group. Could the fast evolution of the comb jellies be misleading us into thinking they arose from an earlier split than they really did?
Are we being fooled by jellies?
We have approached this problem in a new way—directly investigating the possibility that the fast-evolving comb jellies are fooling us. We wanted to ask whether the unequal rates of evolution we see in these animals are likely to result in a wrong answer.
Our new way of working was to dissect the problem by simulating how DNA evolution happens using a computer. We started with a random synthetic DNA sequence representing an ancestral animal. In the computer, we let this sequence evolve, by accumulating mutations, under two different conditions—either in accordance with the sponge-first model or the comb jelly-first model. The sequences evolve according to the branching patterns of each tree.
We ended up with a set of species with DNA sequences that are related to one another in a way that reflects the trees they were evolved on. We then used each of these synthetic data sets to reconstruct an evolutionary tree.
We found that when we built trees using data simulated according to the comb jellies-first model, we could always easily correctly reconstruct the tree. That’s because the bias coming from their fast rate of change actually reinforced the information from the tree—in this case also showing they are the oldest branch. The fact that the tree information and the bias both point in the same direction guarantees we would get the right result. In short, if the comb jellies really were the first branch, then there would be no doubt about it.
When we simulated data with the sponges as the first branch, however, we very often reconstructed the wrong tree, with the comb jellies ending up as the first branch. This is clearly a more difficult tree to get right and the reason is that the tree information—in this case showing that the sponges are the oldest branch—is contradicted by the bias coming from the fast evolving comb jellies (which supports comb jellies-first).
The long branch leading to the comb jellies can indeed cause them to appear older than they really are and this difficulty reconstructing the tree is exactly what we encounter with real data.
So, who came first? The chances are that the genetic analyzes suggesting that comb jellies came first may in fact suffer from not accounting for the bias that makes these animals look older than they really are. In the end, our work suggests that the sponges really are our most distant animal relatives.
All life on Earth evolved from microorganisms in the primordial slime, and billions of years later, the planet’s smallest life forms—including bacteria, plankton and viruses—are still fundamental to the biosphere. They cycle minerals and nutrients through soil, water and the atmosphere. They help grow and digest the food we eat. Without microbes, life as we know it wouldn’t exist.
Now, global warming is supercharging some microbial cycles on a scale big enough to trigger damaging climate feedback loops, research is showing. Bacteria are feasting on more organic material and produce extra carbon dioxide as the planet warms. In the Arctic, a spreading carpet of algae is soaking up more of the sun’s summer rays, speeding melting of the ice.
Deadly pathogenic microbes are also spreading poleward and upward in elevation, killing people, cattle and crops.
So many documented changes, along with other alarming microbial red flags, have drawn a warning from a group of 30 microbiologists, published Tuesday as a “consensus statement” in the journal Nature Reviews Microbiology.
The microbiologists, in their statement, warned about changes they’re already seeing and called for more research to understand the potential impact. The statement “puts humanity on notice that the impact of climate change will depend heavily on responses of microorganisms, which are essential for achieving an environmentally sustainable future,” they wrote.
“Microbes literally support all life on Earth,” said Tom Crowther, an environmental scientist with ETH Zürich, who was among the signers of the statement. “Maintaining and preserving these incredible communities has to be our highest priority if we intend to maintain the existence that we want on this planet.”
What’s known is that global warming increases microbial activity, driving global warming feedback loops, Crowther said.
His research has showed that accelerated microbial activity in soils will significantly increase carbon emissions by 2050. In another study, he showed how global warming favors fungi that quickly break down dead wood and leaves and release CO2 to the atmosphere.
A better understanding of the dynamics would not only help make better global warming projections, but that knowledge also is integral to efforts to reduce CO2 levels in the atmosphere with climate-friendly soils, forest and agriculture, said University of Vermont climate researcher Aimée Classen.
“We know microbes are important for the way the way plants grow,” she said. “Can we harness some of that to help plants be more resistant to changing climate and to sequester more carbon in the soil?”
It’s a Health Issue, Too
There are beneficial microbes, and there are pathogens that are deadly to plants and animals. Global warming is making it easier for some of those killers to spread, reproduce and persist in the environment, said MatthewBaylis, a health researcher at the University of Liverpool who joined the consensus statement.
“We’re seeing a remarkable rate of emergence with new and spreading diseases that are affecting our food production, plants and animals, and our own health,” he said.
It’s not all due to climate change. Some of the spread of disease is simply due to people moving around more and moving plants from place to place in commerce and agriculture.
But there is compelling scientific evidence that global warming has brought malaria to higher elevations in Africa even as its being eradicated in other places, and that it has enabled the spread of bluetongue, a livestock disease that affects sheep, Baylis said.
Millions more people will face the risks of these diseases as the climate warms, he said.
“As the environment warms, pathogens can proliferate in new habitats that were previously too cold, and thereby infect humans in these new habitats,” said Kenneth Timmis, an environmental microbiologist at the Technical University Braunschweig, Germany.
Warming oceans are also changing currents and extreme events like El Niño, which disperses pathogens to new habitats where they cause disease, Timmis said. “This is the case for Vibrio, the cause of cholera and related diseases, of which there has been a series of outbreaks in recent years. In general, water-borne infections increase with increasing temperature,” he said.
Microbes Changes Affect Ocean Food Chain
Charges are also being documented in the Southern Ocean around Antarctica, where marine microplankton take in some 40 percent of all the carbon sequestered by all the oceans and sink it to the seafloor, partly mitigating the buildup of greenhouse gases.
About 90 percent of the world’s ocean biomass is microbial, making it a thick, living soup at a microscopic scale, and global warming brewing up some biological storms with as-yet unknown consequences, said Antje Boetius, a marine microbiologist at the Max Planck Institute in Germany.
The widely reported extreme low Arctic sea ice extent in the summer of 2012 rippled through the ocean’s ecosystems. Huge amounts of microbial life, in the form of diatoms floating in sea ice east of Greenland drifted to the bottom. Boetius said she measured a noticeable change in ocean chemistry as the dead diatoms and associated bacteria piled up at the bottom of the ocean. The research didn’t trace a direct link to harm to marine animals, but it showed how sudden and dramatic extreme climate events can be.
“In the very deep sea, which everyone thinks is protected, we see the velocity of climate change,” she said.
The breeding and feeding cycles of many other Arctic species are closely linked to the timing and location of plankton blooms, so a disruption of the ocean microbe cycles can fundamentally affect the whole food chain, from birds to whales.
Boetius also warned of other tipping points that haven’t been studied yet, including the erosion of organic permafrost soil to the ocean, where aquatic bacteria could digest the material and release huge amounts of methane and CO2 to the air, as well as a potential increase in toxic algae blooms in the Arctic, where they are now still uncommon.
“For everyone that studies ocean microbiology,” she said, “it’s really scary.”
But extensive research over the past 20 years has led to a much better understanding of the environment that suggests it was actually part of an ancient volcano.
In modern volcanic settings, hot fluids circulate in the rocks underground and manifest as hot vents at the bottom of the salty ocean, such as the black or white smokers, or terrestrial hot springs on land where fresh rainwater is available.
What was unclear about the volcanic setting in the Pilbara was whether these hot circulating fluids were indeed discharging on land, producing hot springs—such as those we see in Rotorua, New Zealand—and could we link these hot springs to signs of life?
The smoking gun
Our recent findings from the Pilbara, published today in Nature Communications, provide a smoking gun to a terrestrial hot spring scenario in the form of a particular rock type called geyserite. This was found alongside a variety of textures that indicate life.
Geyserite only forms around the edges of terrestrial hot spring pools and geysers. These are found actively forming today in New Zealand, Yellowstone National Park and Iceland to name a few.
The biological signatures that we’ve found include stromatolites, but also some newly identified microbial textures. This includes a microbial texture (called palisade fabric) that represents microbes that grew upon the ancient sinter terraces —the rocks that form around hot spring pools.
We also found evidence of gas bubbles that must have been trapped in a sticky substance (microbial) in order to be able to preserve the bubble shape.
Importantly, all of these textures are comparable to fossil textures found in modern hot spring settings such as Yellowstone National Park or Rotorua, New Zealand.
Ancient life on land
The Earth’s geological and fossil record is like a thousand-piece puzzle, but we only have a few pieces. Every missing piece we discover helps us to better shape our understanding of life.
But these new findings don’t just extend back the record of geyserite and life living in hot springs on land by three billion years, they also indicate that life was inhabiting the land much earlier than previously thought, by up to 580 million years.
The new discovery has implications for the evolution, and perhaps even the origin, of life on Earth.
Scientists are currently considering two hypotheses regarding the origin of life: that it began in the ocean in hot vents, or alternatively that it began on land in a version of Charles Darwin’s “warm little pond” which was connected to a hot spring system.
The discovery of biological signatures and fossil preservation in such ancient hot springs provides at least a geological perspective of the types of environments available and inhabited by life very early on in Earth’s history.
This may lend weight to the hypothesis that life originated on land and then took a downhill adaptive evolutionary pathway to the salty ocean, whereas the opposite is typically proposed.
Life on Mars
These findings have major implications regarding the search for life elsewhere in the universe, or at least our solar system. Our neighbouring planet, Mars, has long been a target in the search for extraterrestrial life.
Our findings imply that if life ever developed on the red planet, and it is preserved in ancient hot springs on Earth, then there is a good chance it could be preserved in ancient hot springs on Mars too.