Tag Archives: life

The building blocks of life can form on space dust, offering clues to the origins of life

New research proposes that the source of life on Earth may not be on our planet at all, but, in fact, on spaceborne dust.

Nebula NGC 4038. Image via PxHere.

Researchers at Friedrich-Schiller-Universitaet Jena in Germany report that peptides — small-scale proteins — can form on particles of dust under conditions present in outer space. Since all life on our planet relies on proteins, this raises the possibility that the building blocks of life didn’t emerge on Earth at all, but were seeded here from outer space.

The authors propose cosmic molecular clouds as a possible source for these first peptides, although it is currently impossible to confirm that this was the process that seeded life on Earth, or pinpoint a particular structure from whence they came.

Spaceborne, quantumborne — maybe

“Water plays an important role in the conventional way in which peptides are created [by the binding together of individual amino acids],” says Dr Serge Krasnokutski of the Laboratory Astrophysics and Cluster Physics Group of the Max Planck Institute for Astronomy at the University of Jena.

“Our quantum chemical calculations have now shown that the amino acid glycine can be formed through a chemical precursor — called an amino ketene — combining with a water molecule. Put simply: in this case, water must be added for the first reaction step, and water must be removed for the second.”

Peptides are an essential building block of living cells as we know them. They perform a variety of functions within the body such as transporting substances, catalyzing chemical reactions, and forming structural elements inside cells. Peptides are chains of amino acids fused together, and the order and type of amino acids that form the chain give the peptide its final properties.

They are quite complex and ordered structures and likely were the first larger biochemical molecules on Earth. As such, researchers are keen to understand how these peptides came to be.

Some other building blocks of life, including amino acids, nucleobases, and sugars, have been found in meteorites before, which gave us some understanding that the very basic bricks from which organic matter is composed could originate in space. However, as we’ve said before, peptides are complex and highly structured, so they require very specific conditions in which to form. Furthermore, these conditions need to change during the process: first, water must be present; it must then be removed.

Krasnokutski’s team was able to show one reaction pathway through which the production of peptides can occur under cosmic conditions, in a process that requires no liquid water.

“Instead of taking the chemical detour in which amino acids are formed, we wanted to find out whether amino ketene molecules could not be formed instead and combine directly to form peptides,” says Krasnokutski. “And we did this under the conditions that prevail in cosmic molecular clouds, that is to say on dust particles in a vacuum, where the corresponding chemicals are present in abundance: carbon, ammonia, and carbon monoxide.”

The team validated their theory through experiments using an ultra-high vacuum chamber. This experiment involved the use of substrates that mimic cosmic dust, which was mixed together with carbon, ammonia, and carbon monoxide. Everything was then kept at one quadrillionth of normal air pressure and minus 263 degrees Celsius to mimic conditions in outer space.

The peptide polyglycine formed from the substrate under these environmental conditions, the team explains — polyglycine is composed of chains of multiple molecules of glycine, an amino acid, and is, therefore, a peptide. The longest single peptide molecule the team observed consisted of eleven amino acid units linked together. The team further reports that they identified the amino acid ketene in the substrate sample. Ketene is an unstable molecule but highly useful for biological life, as it serves as a key catalyst in the production of other essential compounds.

“The fact that the reaction can take place at such low temperatures at all is due to the amino ketene molecules being extremely reactive. They combine with each other in an effective polymerisation. The product of this is polyglycine,” Krasnokutski explains. “It was nevertheless surprising to us that the polymerisation of amino ketene could happen so easily under such conditions.”

“This is because an energy barrier actually has to be overcome for this to happen. However, it may be that we are helped in this by a special effect of quantum mechanics. In this special reaction step, a hydrogen atom changes its place. However, it is so small that, as a quantum particle, it could not overcome the barrier but was simply able to cross it, so to speak, through the tunnelling effect.”

It may be a bit hard to wrap our heads around such results, as exciting as they may be for researchers looking into the origins of life. Suffice it to say, what the team found is that some of the basic building blocks of life form quite readily in outer space if certain materials are present. Although such results don’t prove that life on Earth originates ultimately in space, it does give researchers ample grounds to consider the cosmos as a likely source.

In the end, it may be that we come to the conclusion that life on Earth is spaceborne — and findings such as these may be remembered as the first step towards that conclusion.

It also raises an exciting possibility; if such molecules can form in space, there’s no reason to believe that Earth was the only planet seeded with them. In other words, the findings should increase our confidence that there is life on other planets. The only thing left to see now is if we find it or not.

The paper “A pathway to peptides in space through the condensation of atomic carbon” has been published in the journal Nature Astronomy.

Photosynthesis could be as old as life itself

Photosynthesis has been supporting life for longer than previously assumed, according to a new paper. The finding suggests that the earliest bacteria that wiggled their way around the planet were able to perform key processes involved in photosynthesis.

Image via Pixabay.

Exactly how the earliest organisms on our planet lived and evolved is an area of active interest and research — but not answers are few and scarce. However, a new paper could fundamentally change how we think about this process.

The advent of photosynthesis on a large scale is one of the most significant events that shaped life on Earth. Not only did this process feed bacteria and plants that would then support for entire ecosystems, but it also led to a massive increase in atmospheric oxygen levels, basically making our planet livable in the first place. Oxygen that we and other complex life still breathe to this day.

To the best of our understanding , it took life several billion years to evolve the ability to perform photosynthesis. However, if the findings of this new study are confirmed, it means complex life could have appeared much earlier.

A light diet

“We had previously shown that the biological system for performing oxygen-production, known as Photosystem II, was extremely old, but until now we hadn’t been able to place it on the timeline of life’s history. Now, we know that Photosystem II show patterns of evolution that are usually only attributed to the oldest known enzymes, which were crucial for life itself to evolve.”

The team led by researchers from Imperial College London studied the evolutionary process of certain proteins that are crucial for photosynthesis. Their findings show that these could possibly have first appeared in the very early days of life on Earth.

They traced the ‘molecular clock’ of key proteins involved in the splitting of water molecules. This approach looks at the time between ‘evolutionary moments’, events such as the emergence of different groups of cyanobacteria or land plants that carry a version of these proteins. They then used this to calculate the rate at which the proteins evolved over time — by backtracking this rate, researchers can estimate when a protein first appeared.

A comparison with other known proteins, including some used in genetic data manipulation that should (in theory) be older than life itself, as well as comparison with more recent events, suggests that these photosynthesizing enzymes are very old. According to the team, they have nearly identical patterns of evolution to the oldest enzymes — suggesting they evolved at a similar rate for a similar time.

Based on what we know so far, type II photosynthesis (which produces oxygen) likely appeared around 2.5 billion years ago in cyanobacteria (blue-green algae), with type I likely evolving some time before that. But there’s something that doesn’t really mesh with that timeframe: we know that there were pockets of atmospheric oxygen before this time. This means that biological communities were around to produce said oxygen even before the 2.5 billion years ago mark, since oxygen is extremely reactive and doesn’t last long in nature without binding to something. Researchers have been trying to reconcyle this for a while.

The current findings could help make everything fit. According to the team, key enzymes that underpin photosynthesis were likely present in the earliest bacteria on Earth. There’s still some uncertainty about this, as life on our planet is at least 3.4 billion years old, but it could be older than 4 billion years.

The first versions of the process were probably simplified, very inefficient versions of the one seen in plants and algae today. It took biology around one billion years to tweak and refine the process, which eventually led to the appearance of cyanobacteria. From there, it took two more billion years for plants and animals to colonize dry land, with the latter breathing oxygen produced by the former.

One interesting implication of these findings is that it could mean life would evolve much quicker and easier on other planets than previously assumed. We tend to estimate this based on how quickly and easily life appeared and then developed on Earth.

The paper “Time-resolved comparative molecular evolution of oxygenic photosynthesis” has been published in the journal Biochimica et Biophysica Acta (BBA) – Bioenergetics.

Phosphine on Venus? It’s probably just sulfur dioxide

Enthusiasm over a Venusian compound associated with life has been quenched by a new study. It’s probably just sulfur dioxide, researchers now believe.

A 3D perspective view of the surface of Venus. Image credits: NASA/JPL.

Phosphine is a colorless, flammable, toxic gas compound — not something you’d be thrilled to see in most cases. But back in September, researchers got really excited about phosphine because it detected in the atmosphere of Venus.

For all its toxicity, phosphine can be produced by life. Finding phosphine on the hellish Venus suggests that life could perhaps exist on Venus, which understandably made a lot of astronomers very curious.

But right from the get-go, some were skeptical about the study. Just one month later, another group of researchers tried to find the phosphine themselves (using telescopes), but couldn’t. Two other groups reprocessed the same data used in the first study and also couldn’t find evidence for phosphine.

We’re not really sure what happened in the first study, but currently, the Nature page where the study is published reads:

“The authors have informed the editors of Nature Astronomy about an error in the original processing of the ALMA Observatory data underlying the work in this Article, and that recalibration of the data has had an impact on the conclusions that can be drawn. Nature Astronomy is working with the authors to resolve the matter.”

Now, a new study seems to put the final nail in the Venusian phosphine theory.

“Instead of phosphine in the clouds of Venus, the data are consistent with an alternative hypothesis: They were detecting sulfur dioxide,” said co-author Victoria Meadows, a UW professor of astronomy. “Sulfur dioxide is the third-most-common chemical compound in Venus’ atmosphere, and it is not considered a sign of life.”

Instead of looking for the phosphine in the telescope data, Meadows and colleagues tried a different approach: they created models of what could be observed on Venus. They found that sulfur dioxide can not only explain the observations, but is also consistent with what we already know of Venus.

Venus is as mysterious as ever. Image credits: NASA / JPL.

The initial phosphine study used the Atacama Large Millimeter/submillimeter Array (ALMA) and the James Clerk Maxwell Telescope (JCMT) to make the observations, focusing on the 266.94 gigahertz frequency. Both phosphine and sulfur dioxide absorb radio waves close to this frequency. So what researchers observed could have been sulfur dioxide. The new study modelled how the signals would be picked up by the JCMT and ALMA telescopes.

“This is what’s known as a radiative transfer model, and it incorporates data from several decades’ worth of observations of Venus from multiple sources, including observatories here on Earth and spacecraft missions like Venus Express,” said lead author Andrew Lincowski, a researcher with the UW Department of Astronomy.

There’s another reason why the previous observations are very unlikely to be phosphine, researchers say: the initial signal was found not in the planet’s cloud layer, but far above it, where phosphine would likely be destroyed within seconds, but sulfur dioxide would be more stable.

“Phosphine in the mesosphere is even more fragile than phosphine in Venus’ clouds,” said Meadows. “If the JCMT signal were from phosphine in the mesosphere, then to account for the strength of the signal and the compound’s sub-second lifetime at that altitude, phosphine would have to be delivered to the mesosphere at about 100 times the rate that oxygen is pumped into Earth’s atmosphere by photosynthesis.”

The team also found that the ALMA antenna configuration had an unfortunate side effect: signals from gases like sulfur dioxide give off weaker signals than gases distributed over a smaller scale.

“They inferred a low detection of sulfur dioxide because of that artificially weak signal from ALMA,” said Lincowski. “But our modeling suggests that the line-diluted ALMA data would have still been consistent with typical or even large amounts of Venus sulfur dioxide, which could fully explain the observed JCMT signal.”

“When this new discovery was announced, the reported low sulfur dioxide abundance was at odds with what we already know about Venus and its clouds,” said Meadows. “Our new work provides a complete framework that shows how typical amounts of sulfur dioxide in the Venus mesosphere can explain both the signal detections, and non-detections, in the JCMT and ALMA data, without the need for phosphine.”

So where does this leave us? We know that Earth’s atmosphere contains small amounts of phosphine, and life may produce phosphine. At this point, it seems more likely that previous observations aren’t of phosphine. But venus also remains as mysterious and ever — with a toxic atmosphere, acidic clouds, and scorching hot temperatures, it’s not the place where you’d expect any life form to exist. Then again, we can’t say that for sure, either.

The study has been published in the journal Nature Astronomy.

Million-year-old dormant microbes beneath ocean floor push life to its absolute limits

Every living creature requires energy in order to subsist, multiply, and pass on its genes. How much energy an animal requires depends on their habitat and size, among many other things. But some cells require so little energy, it just boggles the mind.

Recently, researchers have identified microbial cells that live in sediments kilometers beneath the ocean floor that require a tiny fraction of a calorie to survive. In fact, many of these cells may be up to 100 million years old, something that is owed to their suspended animation state.

Speaking to Quanta Magazine, James Bradly, a geobiologist at Queen Mary University of London and the lead author of a new study that modeled the suboceanic biosphere, said that “This entire biosphere of cells, equivalent in size to the world’s soils, hardly has enough energy to survive.”

Bradly, along with colleagues from universities across the world, employed existing data from previous drilling operations and lab experiments, which they modeled to extrapolate a detailed profile of sub-seafloor sediments.

Researchers projected values like the age of the sediments, the density of cells living inside them, which nutrients are available to these cells, and the rate at which the cells metabolize the nutrients. The findings were quite staggering.

When the researchers calculated the power consumption of the dormant cells living inside the sediments, they found that they were close to the absolute theoretical limit for energy requirements to sustain life.

These sub-seafloor microbes use only 0.1% of the power consumed by creatures living in the upper 200 meters of the ocean. The buried microbes survive at power levels orders of magnitude lower than any organism ever measured in a laboratory, the authors reported in the journal Science Advances.

Previously, in 2015, Douglas LaRowe and Jan Amend, both at the University of Southern California in Los Angeles, estimated the lowest amount of power required to sustain life. Even life that is dormant for millions of years in a zombified state waiting for the right conditions for reanimation needs at least some energy for fundamental biological processes like the repair of DNA damage.

Power per cell (watts) calculated on a global scale and depth-integrated for the (A) oxic, (B) sulfate-reducing, and (C) methanogenic sedimentary layers. White areas denote absence of the corresponding catabolic zone. Credit: Science Advances.

Even if an individual cell doesn’t divide, it would still need at least a zeptowatt, or 10−21 watts, in order to survive. The sub-seafloor microbes are just slightly above this threshold.

Some of these microbes may be up to 100 million years old, researchers report. Given their phenomenally low energy requirements, this all might change how biologists see cellular evolution.

The findings also open the possibility that life may exist in places that scientists had previously discarded as impossible habitats — and this includes other planets, as well.

The sediment samples that were used for the new theoretical model are around 2.6 million years old. However, deeper sediments might house even more starving cells, pushing energy requirements further to the brink.

Researchers list the 10 lifestyle choices most likely to kill you

We all want a long, happy life, but how does one get it? New research from the University of British Columbia (UBC) can’t tell us, but it will tell us which social factors were most associated with death between 2008 and 2014.

Image via Pixabay.

Smoking, alcohol abuse, and divorce were the three closest-linked factors to death during this time interval out of a list of 57 social and behavioral factors. The team used data collected from 13,611 U.S. adults between 1992 and 2008, tying it to which factors applied to those who died between 2008 and 2014.

A good life

“It shows that a lifespan approach is needed to really understand health and mortality,” said Eli Puterman, Assistant Professor at the University of British Columbia’s school of kinesiology and lead author of the study.

“For example, instead of just asking whether people are unemployed, we looked at their history of unemployment over 16 years. If they were unemployed at any time, was that a predictor of mortality? It’s more than just a one-time snapshot in people’s lives, where something might be missed because it did not occur. Our approach provides a look at potential long-term impacts through a lifespan lens.”

The research was prompted by the observation that life expectancy in the U.S. stagnated, as compared to those in other industrialized countries, for the last three decades (only picking up recently). Medical and biological factors definitely have a huge impact, so they were omitted from this study in order to make room for social, psychological, economic, and behavioural factors.

Data was obtained from the U.S. Health and Retirement Study, a nationally-representative study with participants from 50 to 104 years old. While obviously still limited — the survey didn’t capture factors such as food insecurity or domestic abuse — its results can help us understand, in broad lines, which factors or coupling of factors seemed most closely aligned with death for the participants.

A total of 57 factors was analyzed. Out of this list, the 10 most closely associated with death, in order, were:

  • Being a smoker
  • A history of divorce
  • Past or present alcohol abuse
  • Going through financial difficulties recently
  • A history of unemployment
  • A history of smoking
  • Feeling lower levels of life satisfaction
  • Having never married
  • Having relied on food stamps in the past or presently
  • Negative affect

“If we’re going to put money and effort into interventions or policy changes, these areas could potentially provide the greatest return on that investment,” Puterman said.

While smoking has long been identified as a driver of preventable death, the weight of factors such as negative affect or unemployment is surprising. Given how important they were determined to be here, the team says that targeting them with interventions might be a good idea. However, it’s not yet clear what such interventions would look like, whether these factors can be targeted as such, and whether interventions here would actually lead to a reduction in the risk of death.

The paper “Predicting mortality from 57 economic, behavioral, social, and psychological factors” has been published in the journal Proceedings of the National Academy of Science.

Australian men have the longest life expectancy

Australian men live the longest of them all.

New research from The Australian National University (ANU). reports that Australian men are now longer-lived than any of their counterparts elsewhere on Earth. The study relies on a new method of measuring life expectancy, one which accounts for the historical mortality conditions that older generations lived through.

A country for old men

“Popular belief has it that Japan and the Nordic countries are doing really well in terms of health, wellbeing, and longevity. But Australia is right there,” said Dr. Collin Payne, co-lead author of the study.

“The results have a lot to do with long term stability and the fact Australia’s had a high standard of living for a really, really long time. Simple things like having enough to eat, and not seeing a lot of major conflict play a part.”

According to the authors, Australian men live, on average, to the ripe old age of 74.1. Australian women ranked second globally, after their Swiss sisters. The study drew data from 15 countries with high life expectancies in Europe, North America, and Asia.

The team grouped people by their year of birth, which helped them separate ‘early’ deaths from ‘late’ ones — this baseline allowed them to tell whether someone could be considered an ‘above-average’ survivor or not.

“Most measures of life expectancy are just based on mortality rates at a given time,” Dr Payne said. “It’s basically saying if you took a hypothetical group of people and put them through the mortality rates that a country experienced in 2018, for example, they would live to an average age of 80.

This, however, leaves out part of the picture — for example, it doesn’t give any information regarding “the life courses of people, as they’ve lived through to old age.” The team wanted their approach to take this into account — for example, it also factors in mortality rates from 50, 60, and 70 years ago. Such an approach allows the team to tell whether someone has reached or exceeded the life expectancy of their own cohort, rather than the aggregate whole.

Dr. Payne says that any Australian man who lived over 74 years of age has outlived half of his cohort (other Australian men born the same year), making him an above-average survivor. One who died before the age of 74 didn’t live up to his cohort’s life expectancy.

Apart from the conditions in Australia proper, other effects helped put the men of the Dry Continent on the top of the list too.

“[Life expectancy] figures are higher here than anywhere else that we’ve measured life expectancy,” Dr. Payne says. “Mortality was really high in Japan in the 30s, 40s and 50s. In Australia, mortality was really low during that time.”

“French males, for example, drop out because a lot of them died during WW2, some from direct conflict, others from childhood conditions.”

The team hopes to get enough data together to see how the rankings have evolved throughout the last 30 or 40 years.

The paper “Tracking progress in mean longevity: The Lagged Cohort Life Expectancy (LCLE) approach” has been published in the journal Population Studies.

Credit: American Chemical Society.

Scientists uncover new insights into the origin of life

New research investigated whether early Earth could have supported some of the conditions required for the building blocks of life — as proposed by a famous experiment. Turns out it did.

Credit: American Chemical Society.

Credit: American Chemical Society.

How did we get here? That’s one of the big questions that has been vexing humans probably since we first became conscious. Thanks to the theory of evolution by natural selection, scientists are confident that our species evolved from a common ancestor that we share with other apes alive today. However, Homo sapiens represents a single twig on a branch of the evolutionary tree that reaches back some seven million years. If you follow these branches all the way to the stem, you’ll eventually reach ground zero: the very first lifeform out of which all other life evolved.

Although the Earth is thought to be 4.5 billion years old, the oldest rocks on the record are about 4 billion years old. Not long after this period, tantalizing evidence of life emerges, including 3.7-billion-year-old stromatolites(layered structures created by bacteria) found in Greenland and 4-billion-year-old stromatolites found in the Labrador Peninsula in Canada.

In 1953, chemists Harold Urey and Stanley Miller conducted one of the most famous experiments of the past century, commonly known as the primordial soup experiment. In order to find out how the first signs of life on Earth surfaced, the scientists exposed a mix of gases to a lightning-like electrical discharge to create amino acids. Amino acids are very important because they form proteins, which, in turn, form cellular structures and control reactions in living things. Remarkably, when water, methane, ammonia, and hydrogen — all chemicals present on early Earth — were hit by the simulated lightning, they reacted to form hydrogen cyanide, formaldehyde, and other intermediate molecules that reacted further to generate amino acids, along with other biomolecules.

But some scientists think that this experiment relies on too many things coming together. Early Earth — whose conditions are still rather poorly understood — was wrapped in a hazy atmosphere which would have made it very difficult for lightning and ultraviolet light to reach the planet’s surface.

However, that doesn’t mean that there weren’t other alternative forms of energy that could have jump-started these primordial reactions. Indian researchers at the CSIR-National Chemical Laboratory led by Kumar Vanka wondered if heat from ocean waters — which 4 billion years ago were nearly boiling — might have been one such driving force.

In their experiment, Vanka and colleagues used an ab initio nanoreactor that simulates how mixtures of molecules collide and react, forming new molecules. Their results suggest that ancient ocean heat was enough for hydrogen cyanide and water to mix and form the molecules required to produce the amino acid glycine, as well as the precursors of RNA.

Writing in the journal ACS Central Science, the authors conclude that these reactions are both thermodynamically and kinetically feasible, meaning they do not require a catalyst or a lot of energy.

We might never find out exactly how life first emerged on Earth but the fact that there are multiple pathways that could have given rise to it offers some exciting possibilities. It suggests that maybe the conditions necessary for life to form aren’t all that singular, so perhaps many other planets elsewhere in the galaxy and beyond are blessed with this rare gift.

Cycling first person photo.

If you want to find your passion, keep a first-person perspective on life

A new study shows that we can smash through pre-existing beliefs and remember what we find interesting or enjoyable.

Cycling first person photo.

Image via Pixabay.

We all have some idea of what we like, and hopefully, we spend our time doing as much of those things as possible. The really lucky ones among us may also manage to make a career out of something we’re passionate about, but new research shows that we may have a distorted view of this subject. Pre-existing self-beliefs and cultural stereotypes, the authors report, can alter your memory of certain events and how interested you were in them. Essentially, this mechanism sometimes makes us forget where our passions lie because they don’t fit into our idea of what we ‘should be’.

However, we can overcome this dynamic.

Walk a mile in your shoes

“When we are developing our interests and looking back on our memories, I don’t think we realize how biased we can be by our pre-existing beliefs,” said study lead author Zachary Niese, who participated in the research as a doctoral student in psychology at Ohio State.

“People think they know themselves and know if they liked something or not, but often they can be misled by their own thoughts.”

Niese gives the example of a young girl who genuinely enjoyed participating in a science project at a summer camp while it was ongoing. However, upon her return home, she’s reminded that “science is not for girls“, and this comment can change the way she remembers her experience of the project. In effect, this dynamic replaces the feelings of enjoyment in her memories with the ‘proper’ ones of being bored by science.

In a series of four recently-published papers, Niese and her colleagues found consistent evidence that this dynamic is real; people can “forget” how much they enjoyed a particular activity because of what they believed going in, they explain.

Luckily for us, they’ve also found an efficient tool to break the bias. It’s as simple as visualizing an activity from a first-person perspective. For the girl in the example above, simply visualizing herself being at camp and picturing exactly what she did in the project will help put her back in touch with her feelings at the moment.

“We can use imagery as a tool to tap into our memories and more accurately identify what our actual experiences are instead of relying on our old beliefs,” said study co-author Lisa Libby, associate professor of psychology at Ohio State.

“People sometimes have experiences that are inconsistent with what they think about themselves. We may think we don’t like math, so if we enjoy a math class, that doesn’t fit in with our view of ourselves, so we dismiss that positive experience. That’s what using first-person visual imagery helps overcome.”

Perspective matters

The team says this approach works because it changes the frame of mind with which we process that particular event. Viewing it from a first-person perspective forces us to think about and pay attention to how the event made us feel, Niese explains. In contrast, a third-person perspective is more abstract and forces us to imagine how we look from the outside — social norms and our pre-existing beliefs have much more sway here.

The team shows that imagery perspective is so powerful that we can change how people process events by merely showing them photographs taken from one visual perspective or the other, Niese adds.

In one of their experiments, the team worked with 253 undergraduate women, which they first surveyed about their interest in science. A few days later, the participants were asked to play a computer simulation game in which the objective was to create a balanced ecosystem.

Players could achieve this by tweaking how much grass, as well as the number of sheep and wolves that were present. Some of the women played an interesting version of the game (where they had complete control) while others played a ‘deliberately boring’ version (where they could run through predetermined settings rather than make any actual choices). Each of the students was asked to complete a task designed to influence their frame of mind in the moment. During this task, the researchers talked about the game as a science task (this was meant to prime participants) and then showed all the women a series of images and told them to pay attention to each one and try to form an impression of it in their mind.

The images showed an everyday action that differed only in whether the photo was taken from the first-person or third-person perspective. For example, the image could show a person cleaning a spill from a first-person or a third-person. Each participant saw all photos in either the first-person or third-person perspective. After this task, they were asked how interesting they found the ecosystem simulation game as a science task.

The team used the baseline value of their interest in science the women provided on the first day as a reference. All in all, the researchers report, those who viewed the third-person photos reported interest in the game that was very similar to how much interest they reported in science earlier. This was true both for those that played the boring or interesting version of the game. In other words, their pre-existing beliefs completely blinded them to how interesting the game actually was, Niese said.

The women who viewed the first-person photos didn’t show this bias. They accurately reported more interest in the game if they played the interesting version than if they played the boring version. The team says this shows that this group was able to accurately recall how interesting the game was, regardless of their individual interest in science. First-person imagery helped women see how interesting an activity actually was rather than be biased by their pre-existing beliefs, Niese said.

At the end of the study, the researchers offered participants three future “opportunities to do more things like the science task you completed today.” Those who played the interesting version of the simulation and who viewed the first-person photos were more likely than others to show greater interest in future science activities.

“Part of what is so interesting and surprising about our study is that a simple manipulation — just the way people think about a past event — is changing their conclusions about what they’re doing and whether they’re interested or not,” Niese said.

“It’s something people could do on their own if they wanted to and gain these benefits in situations where cultural stereotypes or pre-existing beliefs might be likely to bias their judgment or cloud their memories.”

The paper “I can see myself enjoying that: Using imagery perspective to circumvent bias in self-perceptions of interest” has been published in the Journal of Experimental Psychology: General.

Rusted metal.

Iron-breathing bacteria might have delayed Earth’s oxygenation for almost one billion years

New research shows that early life on Earth relied on a completely different type of photosynthesis — and that delayed the formation of the atmosphere as we breathe it today.

Rusted metal.

Image via Pixabay.

It’s no understatement to say that life today is wholly dependent on photosynthesis. Not only does it power plants (which directly or indirectly feed everybody else), but it also provides the oxygen we breathe. At least as far as the oxygen-producing photosynthesis of today is concerned. This reaction is what led to the appearance of free oxygen in Earth’s atmosphere, something which was unheard of 2.3 billion years ago (as oxygen is very reactive).

However, we have evidence that oxygen-releasing photosynthesis evolved much earlier in our planet’s history, even as early as 3 billion years ago. New research looking into why Earth’s atmosphere took so long to oxygenate suggests that it may simply have been a case of good ol’ fashioned competition at play.

Oxygently

“The striking lag has remained an enduring puzzle in the fields of Earth history and planetary science,” says Christopher Reinhard, an assistant professor in the School of Earth and Atmospheric Sciences (EAS) and the paper’s corresponding author.

Reinhard and his colleagues, led by EAS postdoctoral researcher Kazumi Ozaki, suggest that an older form of photosynthesis may have delayed the oxygenation of Earth’s atmosphere. Chemical conditions in Earth’s early oceans helped prop-up this competitor, against which oxygen-releasing photosynthesizers could not compete effectively at the time.

Modern photosynthesizers break apart water and release oxygen gas. Primitive ones, the team explains, substitute iron ions for water — and release rust instead of oxygen gas. Through a combination of experimental microbiology, genomics, and large-scale biogeochemical modeling, the team found that these primitive photosynthesizers are “fierce competitors for light and nutrients,” Ozaki explains.

“We propose that their ability to outcompete oxygen-producing photosynthesizers is an important component of Earth’s global oxygen cycle,” Ozaki, now an assistant professor in the Department of Environmental Science at Toho University, in Japan, adds.

The findings help us better understand how geology and the biosphere worked to change the Earth’s atmosphere into what we have today. It also helps us better understand the path life took on our planet; as much as oxygenation was a boon to animals like us, it was an environmental catastrophe for organisms at the time. The findings could also help us refine our search for Earth-like planets, or planets harboring alien life, as they give us a better understanding of how life itself can change a planet — and to what extent.

“Our results contribute to a deeper knowledge of the biological factors controlling the long-term evolution of Earth’s atmosphere,” Ozaki says. “They offer a better mechanistic understanding of the factors that promote oxygenation of the atmospheres of Earth-like planets beyond our solar system.”

The results “yield an entirely new vantage from which to build theoretical models of Earth’s biogeochemical oxygen cycle,” Reinhard adds.

The paper “Anoxygenic photosynthesis and the delayed oxygenation of Earth’s atmosphere” has been published in the journal Nature.

Credit: NASA.

Mars may have been habitable more than 4.4 billion years ago

A new study suggests that Mars may have exhibited conditions fit for harboring life as early as 4.48 billion years ago, which would predate the earliest evidence of life on Earth by half a billion years.

Credit: NASA.

Credit: NASA.

The solar system’s early history was wrought with violence, filled with rock and debris flying everywhere. This is evidenced by the countless craters that dot the surface of virtually every planet, moon, and even asteroid, in the solar system. Chemical analysis shows that each of these bodies must have formed and cooled before these impacts began about 4 billion years ago, during a time known as the Late Bombardment Period.  Eventually, the impacts became smaller and infrequent, allowing life to develop on Earth — and possibly elsewhere, too.

When exactly this heavy bombardment ended has always been a matter of debate among scholars. In a new study, astronomers at Western University analyzed minerals from the oldest-known Martian meteorites. The team imaged tiny grain samples from the meteorites down to the atomic level, revealing that they are almost unchanged since they crystalized on the surface of Mars eons ago.

In comparison, samples taken from impact sites on Earth and its moon show that more than 80% of the studied grains had been altered by the intense pressure and heat of the impacts. This all means that heavy bombardment on Mars ended by the time the analyzed minerals formed some 4.48 billion years ago.

According to the researchers at Western University, the Martian surface could have been habitable around the time it is believed that water was abundant there. Based on this new timeline, the researchers believe there was a 700-million-year period between 3.5 billion and 4.2 billion years ago when Martian life could’ve thrived. Because water was also present on Earth by this time, it is plausible that life in the solar system may have started much earlier than previously accepted.

“Giant meteorite impacts on Mars may have actually accelerated the release of early waters from the interior of the planet setting the stage for life-forming reactions,” Western researcher Desmond Moser said. “This work may point out good places to get samples returned from Mars.”

It also means that there’s a chance that if there was ever life on Mars, it could have first appeared there before life on Earth. There’s also a chance that life originating on Mars may have migrated to Earth via meteorites, although this is purely the author speculating at this point.

Plant soil.

What is soil? Here’s the inside scoop

Ground beneath your feet — all planets have it (yes even gas giants). But the one on our Earth is a little different from those in other places. So, what exactly is soil, and what makes ours stand out?

Plant soil.

Image via Pixabay.

Soils are actually very complex things. They’re a mix of solid material — both organic and inorganic — with fluids such as water and air, with a helping of living organisms thrown in to tie everything together. It’s a very dynamic material, one that responds to factors such as climate, terrain, biology, and human activity to name a few. It’s also continuously developing. Depending on where on Earth you look, and when, soils take on unique properties. It’s so complex, in fact, that soils are treated as ecosystems unto themselves.

However, life as we know it would be impossible without soil. So, everybody, grab your spades and let’s take a look at what exactly soil is.

The most bare-bones definition of soil is that it is a mixture of sand, clay, silt, and humus (not the tasty spread). In more geologically-savvy talk, soil is the unconsolidated mineral and/or organic material that forms on the immediate surface of the Earth. According to the Soil Science Society of America Glossary of Soil Science Terms, soil is also “subjected to and shows effects of genetic and environmental factors of: climate (including water and temperature effects), and macro- and microorganisms, conditioned by relief, acting on parent material over a period of time.” In other words, soils represent a mixture of geology and biology, and they are, quite literally, the substrate that fosters life on dry land.

The inorganic parts

 

Sand.

Sand is not readily carried by water.
Image credits Andrew Martin.

The ‘geology’ part includes the inorganic elements of soil — mainly ground-up, weathered rocks and minerals. Weathering are the mechanical or chemical processes through which rocks are broken down into smaller pieces. These rocks and minerals are referred to as the soil’s “parent material“. This inorganic fraction represents around 90% by volume of all the solid material in the mix.

Soil texture is mainly produced by the ratios of different types of inorganic material in the soil. We generally classify these by the size of their particles. The three main types are sand, silt, and clay.

Sand is the coarsest of the three, with particles ranging in diameter from 0.0625 mm to 2 mm. Soils that contain more than 85% sand-sized particles by weight are called sand. Its exact composition varies from place to place, but generally, sand is made up of silica (quartz).

Particles in sand are pretty loose and coarse which creates a lot of open spaces for water to flow through. This makes sand very good at draining and filtering water. Its lack of organic material and inability to hold water, however, makes it a very poor environment for plants to grow in.

Silty water.

Silt is easily mixed with water because of how light its particles are, and can be carried over great distances.
Image credits Andrew Martin.

Silt is an intermediate texture, with particles ranging between 0.0039 mm and 0.0625 mm in diameter. To give you a rough idea, dry silt feels like coarse flour in your hands. Add water to it, and it would feel smooth, almost silky to the touch, without being sticky. Silt is much better than sand at holding in water. Due to its smaller-sized particles, it can be transported over long distances by wind (forming loess) or rivers. It is composed mainly of quartz and feldspar.

Silt an important component for fertile soils. Because of the size of its particles, it’s good at holding water for plants to absorb through their roots, but also creates enough open spaces for air pockets to form (more on that later). Smaller particles also mean they can be circulated around an environment to provide fresh minerals for plants. The Nile River, for example, brings huge amounts of fresh silt, rich in organic material, to bear on its banks every time it floods; this has single handedly fed Ancient Egypt’s ascent in the middle of an inhospitable desert. It had such a central role to play in the Egyptians’ life that they adopted the black silt on the Nile’s banks as a symbol of rebirth.

Clay.

Clay can absorb a lot of water — and all that water increases its volume. Clay contracts and breaks apart when it dries and sheds those water molecules.

Clay is the finest type of material on the list. Its texture feels like that of eye shadow. While the exact point at which a particle is no longer considered silt varies depending on which discipline you’re asking, geologists usually consider particles under 2 micrometers to be clay. It’s usually made up of metallic oxides, which make clay quite colorful. These oxides are why clay-fired bricks are red, but clay can come in a wide range of colors.

Clays are made of wide, flat particles — which means that they have large surface areas compared to the other inorganic fractions. This makes them more chemically active than silt or sand and thus, better able to hold nutrients onto their surfaces. As such, clays can help make very fertile soils. Too much clay, however, can dry plants out — clay particles are good at capturing water but not very good at letting it go.

Overall, the inorganic components of soil mainly include silica, with iron and aluminum oxides. They mainly create soil’s texture and structure. Overall, it isn’t of much value to plants, although fractions like clay can transport nutrients.

The organic parts

Apple soil.

Image credits Annette Meyer.

Geology alone isn’t enough to produce soil. Mars, too, has a lot of ground-up, weathered rocks and minerals about its surface. So does the moon — but that’s just barren dirt. The components that set ‘soil’ apart from ‘dirt’, the bits that give it its unique pizzaz, are biological. Soil is pretty dense in organic material, which makes up around 10% of the volume of its solid components. The two main types of organic matter in soil are the living and the non-living fractions.

The latter improves soil’s ability to hold water, improves its nutritive value, and helps form stable aggregates (i.e. it ties everything together). It mostly originates from the microbial decomposition of animal or plant material (such as leaves, roots, soft tissues, or feces). This breakdown process recirculates nutrients through the soil to feed plants. Exactly how fast this material breaks down depends on how homey the soil is for bacteria. Higher decomposition rates occur in warm, moist conditions with good aeration, a favorable ratio of nutrients, with a pH (soil acidity) near neutral, and without pollutants or toxins.

Organic matter content in soil depends on how much of it is added versus how much of it is broken down over a given unit of time. Bacteria first munch on the juicier bits, such as sugars, starch, and certain proteins. More resistant compounds — such as the structural components in cell walls — are decomposed relatively slowly. These compounds, such as lignin and tannin, impart a dark color to soils containing a significant organic matter content. In general, the darker the soil, the more organic material it contains — so the better it is for growing plants.

Compost.

Compost is just organic material slowly breaking down into soil.
Image credits Manfred Antranias Zimmer.

Living organic matter includes the aforementioned bacteria, earthworms, and everything in between. Fungi, actinomycetes, algae (yes, there is algae in soil), and protozoa also make an appearance. These organisms all work together to make soil the complex ecosystem it is, but they can both support and hinder plant growth. They can help plants by decomposing organic matter, fixing nitrogen (which plants can’t do themselves), and by improving soil quality through aggregation, aeration, and drainage. On the other end of the spectrum, they can compete with plants for nutrients or munch on their roots.

Soil structure

Soil profile.

Its a layered dirt cake!
Image credits Colin Smith.

Soils have complex structures to go along with their complex makeup. Dig down through some and you’ll see it’s made of layers, which are also called ‘horizons’. Taken together, all of these horizons form a soil’s profile. As a rule of thumb, almost all soils have three major horizons, and most also have an organic horizon. In order, a soil’s profile can include:

  • An organic/humus horizon. This material is mostly made up of organic matter in various stages of decay. If you’ve ever walked through a thick forest in spring, you may have noticed that there’s a brown, wet, mushy layer of something between the fallen leaves of last year and the ground proper. That’s plant matter that is rapidly being turned into soil and is part of this organic horizon. This layer shows great variation between soils: it’s thin in some, thick in others, and completely absent in some cases.
  • Topsoil. This horizon is mostly made up of minerals from the soil’s parent material mixed in with a healthy heaping of organic matter. It’s a very cozy place, and most plants and animals that live in soil call this layer home.
  • The eluviated horizon. This is a blanket of gravel, sand, and silt particles of quartz or other particularly hardy materials left over after the clay, organic matter, and more soluble minerals have been washed away by water draining through the soil. It has to be noted that water does this to the above horizons as well, but those tend to be replenished through organic decomposition. The eluviated horizon isn’t seen in most soils but is quite often found in older soils and forest soils.
  • The subsoil. This part is packed with minerals and nutrients washed down from the above layers that get stuck here like coffee grounds onto filter paper.
  • Parent material. The inorganic ‘foundation’ from which the soil developed.
  • The bedrock. A solid mass of solid rocks (usually granite, basalt, quartzite, limestone, or sandstone). If the bedrock is close enough to the surface to weather, it can serve as the parent material for the above soil. But, make no mistake — this is rock. This bit isn’t considered soil.

A lot of this column, ideally, is empty air. Fertile, medium-grain soils can reach up to 50% porosity, and all this empty space is crucial for its health. The pores allow air and water to pool and (ideally) circulate through the soil, keeping both its flora and fauna alive.

Pore size (which is dictated by particle size) is important, too, as is the distribution of these pores. If a pore is too small, it traps water too tightly for plants to absorb. That’s why soils with a large clay content aren’t very good for agriculture. We till the land as a way to break it up and temporarily increase its porosity and permeability.

Pores that are too large just let water woosh right through, as we discussed earlier, which is just as bad for plants. Large pores that communicate (i.e. that are connected) with one another allow water and air to move freely through the soil, carrying nutrients around. However, smaller pores are better if you’re dealing with drought — they store water better.

As far as flora is concerned, pores can keep different populations of bacteria separate from one another. This is actually pretty good news since it keeps the strains from competing with one another directly. As such, soil porosity allows for multiple organisms that occupy the same ecological niche to coexist, which improves its resilience to shocks such as pollution or climate change.

It’s easy to take the soil under our feet for granted — after all, it’s just dirt in our soles. But hopefully, I’ve helped you see a glimpse of the living, breathing ecosystem that underpins all of the life on dry land, and most of the life on Earth. So the next time you visit the park, spare a moment to think of all the hard work that’s going on beneath your shoes — we wouldn’t be here without it.

Scuba Diver.

Robots and AI can help us better understand deep sea species, study reports.

Robots and artificial intelligence may be just what we need to meet the denizens of the ocean floor, a new study reports.

Scuba Diver.

Image via Pixabay.

Artificial intelligence (AI) has an important role to play in helping us understand the large variety of species living on the ocean floor, new research from the University of Plymouth reports. Such systems could finally allow marine researchers to push past the efficiency bottleneck created by human users analyzing recordings from the depths of the sea.

Davy Jones’ locker

“Autonomous vehicles are a vital tool for surveying large areas of the seabed deeper than 60m [the depth most divers can reach],” says PhD student Nils Piechaud, lead author on the study. “But we are currently not able to manually analyse more than a fraction of that data.”

“This research shows AI is a promising tool but our AI classifier would still be wrong one out of five times, if it was used to identify animals in our images.”

The new study analyzed the effectiveness of a computer vision (CV) system in taking over the role of humans in analyzing deep-sea images. All in all, the team found, such as system is around 80% accurate in identifying various animals in images of the seabed but can be up to 93% accurate for specific species if enough data is used to train the algorithm. The authors say that such results suggest CV could soon be routinely employed to study marine animals and plants. In such a case, it would lead to a major increase in data availability for conservation research and biodiversity management, they add.

“But we are not at the point of considering it a suitable complete replacement for humans at this stage,” Piechaud notes.

The team used Google’s Tensorflow, an open access library, to teach a (pre-trained) neural network to identify individuals of deep-sea species found in images taken by autonomous underwater vehicles (AUV). One of these AUVs, known as Autosub6000, was deployed back in May 2016 on the north-east side of Rockall Bank, UK, and collected over 150,000 images in a single dive. Around 1,200 of these images were manually analyzed, containing 40,000 individuals of 110 different kinds of animals (morphospecies), most of them only seen a handful of times.

Manual annotation ranged from 50 to 95% on this dataset; however, it was very slow. And, as you guessed from that ‘ranged’ part, it was quite inconsistent across different teams and work intervals. The automated method reached around 80% accuracy, approaching the performance of humans with a clear speed and consistency advantage. The software worked particularly well for certain morphospecies. For example, it correctly identified a type of xenophyophore 93% of the time.

So should we just use it instead of marine biologists? Well, the authors of this present study don’t think that would be a good idea. The study makes a case for automated systems working in tandem with marine biologists, not replacing them. The AIs could greatly enhance the ability of scientists to analyze the data before them.

And combining the ability of high-tech AUVs to survey large areas of the seabed, the fast data-crunching ability of AI, and expertise of marine biologists together could massively speed up the rate of deep-ocean exploration — and with it our wider understanding of marine ecosystems.

“Most of our planet is deep sea, a vast area in which we have equally large knowledge gaps,” says Dr Kerry Howell, Associate Professor in Marine Ecology and Principal Investigator for the Deep Links project.”

“With increasing pressures on the marine environment including climate change, it is imperative that we understand our oceans and the habitats and species found within them. In the age of robotic and autonomous vehicles, big data, and global open research, the development of AI tools with the potential to help speed up our acquisition of knowledge is an exciting and much needed advance.”

The paper “Automated identification of benthic epifauna with computer vision” has been published in the journal Marine Ecology Progress Series.

Comet.

Building blocks of life can spontaneously form in outer space

Space may be the final frontier, but it may have also been the first.

Comet.

Image via Pixabay.

Researchers at NASA’s Ames Research Center found new evidence in support of the view that asteroids carried the basic ingredients of life to Earth. In a new study, they report that such compounds can spontaneously form in the conditions of outer space with substances commonlt found the interstellar medium.

From whence we came. Maybe

We actually don’t know that much about how life started on Earth. In fact, we don’t even know if life started on Earth — at least, not its constituent parts. Two main theories compete in this regard. One holds that life emerged in hot springs or deep-sea thermal vents because such areas are rich in the right ingredients. The other states that those ingredients formed up there (way up there) and then crash-landed on the planet on the back of meteorites or comets.

The Ames Research Group team found evidence supporting the latter. They found that one of the fundamental building blocks of life — sugars — can and will spontaneously form in outer space. Sugars are important both from a nutritional value (they pack a lot of energy) as well as a biochemical one: 2-deoxyribose, for example, is a fundamental component of DNA (and also a sugar).

In a lab setting mirroring conditions in outer space, the team managed to spontaneously create 2-deoxyribose. The team cooled a sample of aluminum substrate in a freezer and cooled it down to nearly absolute zero. Afterward, they placed the sample in a vacuum chamber; all in all, this rig was a close simulation of conditions in deep space, they report.

Next, the researchers pumped small quantities of a water and methanol gas mixture similar to that found in the interstellar medium (to simulate its chemical makeup) and blasted the whole thing with UV light (to simulate radiation levels in outer space).

Initially, the test seemed to be a dud — only water ice formed on the sample. After a while, however, the strong UVs melted it down, and subsequent chemical analysis revealed that a small quantity of  2-deoxyribose had formed along with some other sugars. Fresh on the scent, the team then analyzed samples from several carbonaceous meteorites. They found traces of alcohols and deoxysugar acids on these space rocks which.

Although that’s not exactly 2-deoxyribose, the team notes their samples were drawn from a small number of meteorites. It’s quite possible, they add, that others would carry traces of these substances.

The findings add more weight to the to the theory that life got jump-started by space-stuff. However, that isn’t to say it’s definitive proof, or that the two scenarios didn’t take place at the same time, or in tandem. It is, however, a good indicator that the chemical building blocks of life are out there and, given the right environment, they can lead to life.

The paper “Deoxyribose and deoxysugar derivatives from photoprocessed astrophysical ice analogues and comparison to meteorites” has been published in the journal Nature Communications.

Tunneling bot.

Nuclear-powered ‘tunnelbot’ could probe the depths of Europa’s oceans

Researchers at the University of Illinois at Chicago (UoI) have designed a nuclear-powered ‘tunnelbot’ to explore Europa, Jupiter’s ice-bound moon.

Tunneling bot.

Artist’s rendering of the Europa “tunnelbot.”
Image credits Alexander Pawlusik / LERCIP Internship Program, NASA Glenn Research Center.

Europa (the moon, not the continent) has captured the imaginations of space buffs around the world since 1995. That year saw NASA’s Galileo spacecraft’s first flyby around the moon which, along with subsequent investigations in 2003, pointed without a doubt to a liquid ocean beneath the icy surface.

All that water makes Europa a very strong candidate for alien microbial life or at least evidence of now-extinct microbial life. Needless to say, researchers were very thrilled about paying the moon a visit. However, we simply didn’t have any machine capable of pushing through the crust and then braving the oceans beneath — at least, not until now.

We all live in a nuclear submarine

“Estimates of the thickness of the ice shell range between 2 and 30 kilometers [1.2 and 18.6 miles], and is a major barrier any lander will have to overcome in order to access areas we think have a chance of holding biosignatures representative of life on Europa,” said Andrew Dombard, associate professor of earth and environmental sciences at the University of Illinois at Chicago.

Dombard and his spouse, D’Arcy Meyer-Dombard, associate professor of earth and environmental sciences at UoI, are part of the NASA Glenn Research COMPASS team, a multidisciplinary group of scientists and engineers tasked with designing technology and solutions for space exploration and science missions. Together with the team, Dombard presented their new design — a nuclear-powered tunnelling probe — at the American Geophysical Union meeting in Washington, D.C. this week.

The so-called “tunnelbot” is meant to pierce through Europa’s ice shell, reach the top of its oceans, and deploy instruments to analyze the environment and search for signs of life. The team didn’t worry about how the bot “would make it to Europa or get deployed into the ice,” Dombard said, instead focusing on “how it would work during descent to the ocean.”

Such a tunnelbot should be able to take ice samples as it passes through the moon’s shell, water samples at the ocean-ice interface, and it should be able to search the underside of this ice for microbial biofilms, the team explains. Finally, it should also be capable of searching for and investigating liquid water “lakes” within the ice shell.

Two designs were considered for the job: one version of the robot powered by a small nuclear reactor, and another powered by General Purpose Heat Source bricks (radioactive heat source modules designed for space missions). In both cases, heat generated by the power source would be used to melt through the ice shell. Communications would be handled by a string of “repeaters” connected to the bot by optic fibre cables.

NASA is very interested in visiting Europa, particularly because of its potential to harbor life. However, the bot designed by Dombard’s team isn’t an official ‘go’ sign for such an expedition. Whether NASA will plan tunneling, and if one of these designs would be selected for the job, remains to be seen.

Mars may yet hold life in salty subsurface waters

In its current form, Mars isn’t the best place to host life — but some of its subsurface oases may be pretty welcoming, a new study reports.

Credits: NASA.

In order to sustain life, a planet (or any celestial body) must fulfill quite a lot of conditions. You need sufficient gravitational pull, an atmosphere with a specific chemical makeup, a Goldilocks temperature — and that’s just the start of it. All in all, the stars need to align just right to provide the necessary conditions for life to evolve.

Mars definitely fulfills some of those requirements. It’s a rocky planet, lies at a reasonable distance from its star, and shows signs of hosting water. Its atmosphere, however, isn’t conducive to life as we know it. Aside from being very thin (just 6% the density of Earth’s atmosphere on average), it comprises 96% carbon dioxide and only contains traces of free oxygen. Due to the scarcity of oxygen, Mars has been assumed to be incapable of producing environments with sufficiently large concentrations of O2 to support aerobic respiration, researchers write in a new study.

However, there are some places where Mars could, in fact, host life: underground. But the story isn’t that straight-forward.

Here on Earth, oxygen and life go hand in hand. Photosynthesis evolved at least 2.3 billion years ago, and aerobic (or oxygen-breathing) life evolved with it. We haven’t seen any sign of that on Mars, however. Furthermore, life requires liquid water — and with an average surface temperature of -81 degrees Fahrenheit (-63 Celsius), liquid water is a scarce commodity on the red planet. There’s no clear evidence that liquid water exists (or could exist) on Mars’ surface, but there are some hints that liquid water could exist underground, in the form of brine (very salty water).

Water mixed with salt freezes at lower temperatures than freshwater. While pure water will freeze at 32 degrees Fahrenheit (0 Celsius), salty water will still be liquid at that temperature. But salt also reduces the amount of oxygen that water can store, while low temperatures increase the amount of oxygen. So salt, temperature, and oxygen are trapped in a constant push and tow.

To study this dance, Vlada Stamenković and colleagues calculated how much molecular oxygen could be dissolved in subsurface Martian liquid brines. They found that molecular oxygen concentrations are particularly high in the polar regions, and remarkably, some of them could even contain enough oxygen to support aerobic life.

These findings also fit with surface observations, particularly oxidized rocks observed by rovers exploring Mars’ surface.

“That’s the thing of habitability; we never thought that environment could have that much oxygen,” says Stamenković, a planetary scientist and physicist at NASA’s Jet Propulsion Laboratory.

This completely changes our understanding of the potential for life on current-day Mars, he adds. Of course, it doesn’t mean that there is life on Mars — but the fact that could be is already pretty exciting.

The study has been published in Nature Geoscience.

Dickinsonia.

Fossil fats reveal the ‘oldest macroscopic animal’ that lived 558 million years ago

Fossils of an animal that lived 558 million years ago — the oldest animal ever discovered — shed light on the shapes early life took on Earth.

Dickinsonia.

Dickinsonia fossil. Image credits Ilya Bobrovskiy et al., 2018, Science / The Australian National University (ANU)

An international team of researchers, led by members from The Australian National University (ANU), has made a stunning discovery: the team identified intact fat molecules in a fossil of the oldest animal discovered to date. The animal, called Dickinsonia, could grow up to 1.4 meters in length, being formed of rib-like segments.

The discovery yields an unprecedented view into the Ediacaran Biota, the first complex multicellular organisms known to have spawned on Earth. The findings help piece together our own evolutionary history as the Ediacaran lifeforms are the forefathers of each and every animal on the planet today.

Life, Beta Version

The Ediacaran Biota developed roughly 20 million years prior to the Cambrian explosion, a period of rapid evolution of animals in a greater number of species of more complexity than ever before. This period sees complex, multicellular organisms such as mollusks, worms, arthropods, and sponges start to dominate the fossil record — and laid the groundwork for life as we know it today.

Viewed in that light, the Ediacaran Biota is the evolutionary touchstone that made further diversification possible. As such, it is the ancestor of all the animals that ever walked, swam, or flew upon the face of the Earth.

The team’s findings are a paleontologists’ holy grail — they discovered a Dickinsonia fossil so well preserved in a remote area near the White Sea in the northwest of Russia that the tissue still contained molecules of cholesterol, a type of fat that is the hallmark of animal life.

“The fossil fat molecules that we’ve found prove that animals were large and abundant 558 million years ago, millions of years earlier than previously thought,” said Jochen Brocks, paper co-author and Associate Professor at the ANU Research School of Earth Sciences.

“Scientists have been fighting for more than 75 years over what Dickinsonia and other bizarre fossils of the Edicaran Biota were: giant single-celled amoeba, lichen, failed experiments of evolution or the earliest animals on Earth. The fossil fat now confirms Dickinsonia as the oldest known animal fossil, solving a decades-old mystery that has been the Holy Grail of palaeontology.”

Dickinsonia costata.

Artist’s rendition of Dickinsonia costata. Image via Wikimedia.

While paleontology usually looks at the structure of fossils, the team wanted to look at organic matter in the case of Dickinsonia, not just its imprint. This is because the species forms the bridge between ‘old’ biology (which was dominated by bacteria), and the first complex animals. Macrofossils from the Ediacaran are “‘as strange as life on another planet’ and have evaded taxonomic classification, with interpretations ranging from marine animals or giant single-celled protists to terrestrial lichens,” the paper explains. Without a look at their biochemistry, we simply couldn’t know for sure if they were animals or something else.

The main challenge was finding Dickinsonia fossils that still retained organic matter, the team reports.

“Most rocks containing these fossils such as those from the Ediacara Hills in Australia have endured a lot of heat, a lot of pressure, and then they were weathered after that,” explains ANU PhD scholar Ilya Bobrovskiy. “These are the rocks that palaeontologists studied for many decades, which explained why they were stuck on the question of Dickinsonia’s true identity.”

Bobrovskiy traveled to a remote area near the White Sea in the northwest of Russia — a region known for Ediacaran-biota-bearing rocks — to find the fossil the team needed. The Dickinsonia fossil was recovered near the Lyamtsa locality, while a second fossil species used in the study (Andiva) was recovered near Zimnie Gory.

“I took a helicopter to reach this very remote part of the world — home to bears and mosquitoes — where I could find Dickinsonia fossils with organic matter still intact,” he recounts.

The fossils were recovered from rocky outcrops along the White Sea. The cliffs themselves are “60 to 100 meters high” (196 to 328 feet) high, Bobrovskiy explains, which he had to scale in order to investigate.

“I had to hang over the edge of a cliff on ropes and dig out huge blocks of sandstone, throw them down, wash the sandstone and repeat this process until I found the fossils I was after.”

Chemical analysis of the Dickinsonia specimen revealed a “striking abundance of cholesteroids” and a marked difference in several key chemical markers that differentiate the organism from background microbial activity. By contrast, “biomarker signatures of Andiva specimens from the Zimnie Gory locality are less well differentiated from the microbial mat background signal and do not display a clear elevation of cholesteroids relative to the background,” the authors explain.

Further chemical analysis and comparison “firmly place dickinsoniids within the animal kingdom, establishing Dickinsonia as the oldest confirmed macroscopic animals in the fossil record (558 million years ago) next to marginally younger Kimberella from Zimnie Gory (555 million years ago),” the paper concludes.

When Ilya showed me the results, I just couldn’t believe it,” Brocks says. “But I also immediately saw the significance.”

The paper “Ancient steroids establish the Ediacaran fossil Dickinsonia as one of the earliest animals” was published in the journal Science.

It Is Possible Jupiter Could Support Life, Scientists Say

Jupiter and its shrunken Great Red Spot. Credit: Wikimedia Commons.

Jupiter and its shrunken Great Red Spot. Credit: Wikimedia Commons.

A new factor has been added to the debate on whether or not living organisms could exist on Jupiter. You probably know Jupiter is a Jovian planet, a giant formed primarily out of gases. So how could alien life be able to exist in an environment where most of the phases of matter are absent? The answer is simply found in the element of water.

Within the rotating, turbulent Great Red Spot, perhaps Jupiter’s most distinguishable characteristic, are water clouds. Many of the other clouds in this enormous perpetual storm are comprised of ammonia and/or sulfur. Life theoretically cannot be sustained in water vapor alone; it thrives in liquid water. But according to some researchers, the fact alone that water exists in any form on the planet is a good first step.

The Great Red Spot is still a planetary feature which stumps much of the scientific community today. As it has been observed for the past century and a half, the Great Red Spot has been noticeably shrinking. The discovery of water clouds may lead to a deeper understanding of the planet’s past, including whether or not it might have sustained life, as well as weather-related information.

Some scientists have pondered the possibility that, due to the hydrogen and helium content in its atmosphere, Jupiter could be a diamond-producing “factory.” They have further speculated that these diamonds could enter into a liquid state and a rainfall of liquid diamonds would be in the Jovian’s weather forecast.

Likewise, the presence of water clouds means that water rain (a liquid) is not entirely impossible. Máté Ádámkovics, an astrophysicist at Clemson University in South Carolina, had this to say on the matter:

“…where there’s the potential for liquid water, the possibility of life cannot be completely ruled out. So, though it appears very unlikely, life on Jupiter is not beyond the range of our imaginations.”

Scientists are acting accordingly, researching the part which water plays in the atmosphere and other natural systems on Jupiter. They remain skeptical but eager to follow up on the new discovery. They shall also strive to find out just how much water the planet really holds.

Bali eruption.

Ancient volcanism shows our emissions can trigger a mass marine extinction

Ancient volcanism offers a glimpse into the future effects of climate change.

Bali eruption.

Volcanic eruption in Bali, Indonesia.
Image credits Alit Suarnegara.

Right now, global climate patterns are swinging wildly (in geological terms), powered by all the greenhouse gases we’re pumping in the atmosphere. We have some broad idea of what these changes will entail, but we don’t know the details — and not knowing what to expect in such circumstances is quite scary. One thing we do know for sure right now is that the high concentrations of carbon dioxide in the atmosphere are draining oceans of oxygen. It’s happening faster than anything similar we’ve ever seen and has researchers worried and scrambling to find solutions.

For that, however, we’ll need to know what to expect. One team of researchers from Florida State University (FSU) dredged the geological record for similar events to use as a guideline. The magnitude and sheer destructiveness of what they found suggests that we were right to worry.

Volca-no

The team used ancient volcanism as a proxy for today’s anthropic emissions. Millions of years ago, during the Toarcian Oceanic Anoxic Event (T-OAE, during the Early Jurassic), powerful eruptions belched large quantities of carbon dioxide into the atmosphere. Oxygen levels in ocean waters soon plummeted. Most marine life followed suit, leading to a devastating mass extinction.

“We want to understand how volcanism, which can be related to modern anthropogenic carbon dioxide release, manifests itself in ocean chemistry and extinction events,” said study co-author Jeremy Owens.

“Could this be a precursor to what we’re seeing today with oxygen loss in our oceans? Will we experience something as catastrophic as this mass extinction event?”

The team set out to reconstruct ocean oxygen levels during the Early Jurassic in order to better understand the mass extinction event during the T-OAE. Their research reinforces previous findings regarding the (bad) effects of increased ocean temperature and acidification on marine life. However, it also revealed the importance of a third factor, oxygen level change, in leading to such an event.

Toarcian paleogeo.

Image credits Scotese CR (2001), Atlas of Earth History via R. Them et al., 2018, PNAS.

For the study, the team retrieved samples of ancient rock formations from North America and Europe. Thallium isotope analysis performed at the FSU-based National High Magnetic Field Laboratory revealed that oxygen levels in the oceans started to drop several hundred thousands of years before the interval we ascribe to the T-OAE. This initial drop was caused by massive bouts of volcanic activity, they explain, adding that it’s not that different a process from modern anthropic emissions of CO2.

“Over the past 50 years, we’ve seen that a significant amount of oxygen has been lost from our modern oceans,” says Theodore Them, a postdoctoral researcher at FSU who led the study. “While the timescales are different, past volcanism and carbon dioxide increases could very well be an analog for present events.”

“As a community, we’ve suggested that sediments deposited during the T-OAE were indicative of widespread oxygen loss in the oceans, but we’ve never had the data until now.”

High atmospheric levels of carbon dioxide increase average temperatures on the planet. This sets into motion multiple chains of events (chemical, biological, as well as hydrological) that compound to remove oxygen from ocean water. Ultimately, this process resulted in severe oceanic deoxygenation and mass extinction of marine life, which we see in the geological record as the T-OAE.

Extinction event

Sequence of events culminating in the Early Jurassic T-OAE. The massive die-off worked to sequester large amounts of carbon (δ13C line) from the atmosphere, allowing conditions to eventually stabilize. Top bars represent biodiversity.
Image credits R. Them et al., 2018, PNAS.

The findings help flesh out our understanding of how Earth’s systems function. But they also point to a worrying precedent. We’re already seeing signs of ocean acidification, increased average temperatures, and of falling levels of oxygen in ocean water. It’s safe to assume that the interplay between these events will have the same results as in the Early Jurassic. Should we continue pumping greenhouse gases such as CO2 in the atmosphere, we might just usher in an ocean mass extinction upon ourselves — one that will likely take society as we know it down, too.

“It’s extremely important to study these past events,” Them said. “It seems that no matter what event we observe in Earth’s history, when we see carbon dioxide concentrations increasing rapidly, the result tends to be very similar: a major or mass extinction event. This is another situation where we can unequivocally link widespread oceanic deoxygenation to a mass extinction.”

Not all is lost, however. All out tech and know-how put us in this position, that’s true, but it also offers the way out. There are steps we can take to stop or at least slow down the rate of oxygen loss in our oceans, the team notes. For example, maintaining environments that absorb and store carbon dioxide (such as wetlands or estuaries) could help reduce the effect of our emissions. The single biggest change we can make, however, is to de-couple our industries and economies from fossil fuels — efforts are already underway, but it never hurts to double down.

Personal efforts also help. Many of the things you can do to reduce your impact on the planet are also quite healthy and beneficial choices on an individual level: drive less, to reduce the level of emissions you put in the air and get some exercise, too. Eat more veggies, cut out as much meat and dairy as you’re comfortable too, or just be more selective about what type of animal protein you eat — good for your health, your wallet, and the planet! Finally, waste not — it helps to reduce emissions from industry, reduces trash, and will give you a mood boost.

The paper “Thallium isotopes reveal protracted anoxia during the Toarcian (Early Jurassic) associated with volcanism, carbon burial, and mass extinction” has been published in the journal Proceedings of the National Academy of Sciences.

World_geologic_provinces

The Earth had continental crust much earlier than thought — potentially life, too

The Earth might have developed its continental crust much earlier than believed, new research reveals. The findings could have major implications for how we think about the evolution of life on our planet.

World_geologic_provinces

Map showing the world’s geologic provinces.
Image credits United States Geological Survey.

Strontium atoms locked in rocks from northern Canada might rewrite the history of life on Earth. According to new research from the University of Chicago, they suggest that continental crust developed hundreds of millions of years earlier than previously assumed.

Crustally fit

“Our evidence, which squares with emerging evidence including rocks in western Australia, suggests that the early Earth was capable of forming continental crust within 350 million years of the formation of the solar system,” says first author Patrick Boehnke.

“This alters the classic view, that the crust was hot, dry and hellish for more than half a billion years after it formed.”

There are two types of crust covering the Earth: oceanic, which is basically solidified magma, and continental, which is less dense and has a different chemical make-up — most notably, a much higher content of silica. We know that all crust starts out as the oceanic kind, and continental crust later develops on top of this. Geologists have been trying to determine how and at what point continental crust first appeared ever since we’ve known there is such a thing as ‘continental crust’.

However, that’s easier asked than answered. Part of the problem is that the Earth’s crust is continuously recycled over geological timescales — it sinks, melts down, and reforms. This also destroys the evidence geologists would need in order to back-track the process of continental crust formation.

Some fragments of these ancient bits of crust can still be found today, embedded into young rocks as flakes of the mineral apatite. But if they’re not perfectly insulated, they will degrade over time through oxidation, interaction with water, or other chemical and mechanical means.

Luckily, some of the younger minerals also include some that are very durable, such as zircons. These are hardy materials, similar to diamonds, that are very weather-resistant. Even better for a geologist with a mission, zircon can be dated.

“Zircons are a geologist’s favorite because these are the only record of the first three to four hundred million years of Earth. Diamonds aren’t forever — zircons are,” Boehnke said.

The team used strontium isotope analysis to date rocks retrieved from sites in Nuvvuagittuq, northern Canada to determine their age and the amount of silica present as it was forming. Because the flakes of rock they recovered were incredibly tiny — about as thick as a strand of spider silk, five microns across — the team had to use chili.

More specifically, they had to use CHILI (all capitalized). This unique instrument, the Chicago Instrument for Laser Ionization, came on-line last year. It uses laser beams that can be tuned to pick out and ionize strontium atoms, allowing the team to count them. The results of this counting process suggested plenty of silica was present when it formed.

The chemical composition of the crust tells us a lot about the state of the Earth at the time — our planet is like one huge chemistry jar, and every component interacts with all others. Crustal composition directly affects the atmosphere, for example, mostly through oxidation effects. It also alters the composition of seawater and dictates what nutrients are available to any potential organisms. The fact that Earth sported continental crust that early, and that is was so chemically similar to that of today, suggests that conditions at the time weren’t that different from those today. That doesn’t mean the continents looked like they do today (because they didn’t) but geochemical conditions should have been pretty similar to those today.

It could also be a sign that fewer meteorites hit Earth at this time than we assumed — these would pummel the planet, making it hard for continental crust to form.

The findings also suggest we need to take a second look at the processes we believe create continental crust: if the team’s findings are true, they need to work much faster than current models assume.

The paper “Potassic, high-silica Hadean crust” has been published in the journal Proceedings of the National Academy of Sciences.

What if we’re not the first advanced civilization on Earth — How would we know?

A new study raises an intriguing question: are we really the first ones to develop a civilization on Earth? Before you start thinking about aliens or wacky conspiracy theories, think about it this way: if another civilization had developed on the planet at some point in the geological past, how would we know about it? The new research explores that avenue; they call it “The Silurian hypothesis.”

Archaeological Site of Harappa. Image via Wikipedia.

Ancient life

Homo sapiens as we know it evolved some 315,000 years ago. You might think that’s a very long time and in one sense, it is. But at a geological scale, it’s nothing. Primates, as a group, emerged some 55 million years ago, while mammals came to be over 200 million years ago. Reptiles have been on this planet for more than 300 million years ago, and fish popped up more than 500 million years ago. The history of life on Earth is so incredibly long it’s difficult to comprehend it at the human scale.

What we know about these ancient living creatures, we know through fossils. Sure, we complement findings with computer models and the ecological principles we’ve discovered, but fossils are still the pillar of our knowledge of ancient life. But it takes special conditions for a fossil to form, and the results we’ve discovered so far are few and far between compared to the mind-blowing diversity our planet has witnessed.

To make matters even worse, our planet is an active environment and tectonic movement (and other geological processes) can destroy fossils and other clues about ancient environments. So to sum it up, remnants of life are rare, and even those rare bits are often destroyed by the Earth’s geology. Now, think about it this way: wouldn’t the same thing happen to evidence of an ancient civilization?

Remnants of a civilization

If humanity went extinct tomorrow, what would be left of us? The buildings, roads, and all the infrastructure — for a while. They would be engulfed by vegetation in a few years, and almost everything would be destroyed in a few centuries. After a million years, you probably won’t see any evidence that mankind ever existed — at the surface, anyway.

A diligent scientist one million years in the future might be able to tell that a civilization once existed. He’d find isotopic evidence of atomic explosions, an unnatural rise in CO2 emissions, perhaps even some remnants of former structures — but all these have essentially happened in the past century. In their new study, Gavin A. Schmidt (a climatologist with the NASA Goddard Institute for Space Studies) and Adam Frank (an astronomer from the University of Rochester) address this conundrum: are we the first civilization on Earth, and what does this mean for finding life on other planets?

Based on recent astronomical findings, we know that there is a huge number of stars in the galaxy, many of them harboring stars in the habitable zone. The number of planets capable of hosting life might be very high, thus also increasing the chances of intelligent life forms emerging. Scientists are looking for extraterrestrial life more and more — but what about here on Earth, what if there is a previous civilization we’ve still yet to discover? What if we are the scientists million of years in the future, hunting for an ancient industrialized civilization, what would we find?

You’d start with the air, researchers write.

“Since the mid-18th Century, humans have released over 0.5 trillion tons of fossil carbon via the burning of coal, oil and natural gas, at a rate orders of magnitude faster than natural long-term sources or sinks. In addition, there has been widespread deforestation and addition of carbon dioxide into the air via biomass burning.”

You’d move on to geomorphological features, like increased rates of sediment flow in rivers and its deposition in coastal environments, as a result of agricultural processes, deforestation, and the digging of canals. Then, you’d move on to biology, looking for evidence of domesticated animals. But the biggest smoking gun would be synthetic materials. The presence of synthetic materials, plastics, and radioactive elements (caused by nuclear power or nuclear testing) could also leave a significant mark on the geological record, and isotopes could last for millions of years. Finally, you’d look for extinctions caused by the rise of said civilization.

“The clearest class of event with such similarities are the hyperthermals, most notably the Paleocene-Eocene Thermal Maximum (56 Ma), but this also includes smaller hyperthermal events, ocean anoxic events in the Cretaceous and Jurassic, and significant (if less well characterized) events of the Paleozoic,” researchers continue.

A comparison between the Earth and Mars.

After tightening these constraints for Earth, they move on to what we might potentially see on other planets. Mars and Venus might have been habitable millions of years ago, and if we want to see if this was the case, we need to know what to look for.

“We note here that abundant evidence exists of surface water in ancient Martian climates (3.8 Ga), and speculation that early Venus (2 Ga to 0.7 Ga) was habitable (due to a dimmer sun and lower CO2 atmosphere) has been supported by recent modeling studies,” they state. “Conceivably, deep drilling operations could be carried out on either planet in future to assess their geological history. This would constrain consideration of what the fingerprint might be of life, and even organized civilization.”

Journal Reference: The Silurian Hypothesis: Would it be possible to detect an industrial civilization in the geological record? arxiv.org/abs/1804.03748