Tag Archives: oxygen

Climate change is choking the oxygen out of deep water, and it’s putting fish in a double bind

Being a fish was never easy, but a new paper reports that it’s been getting harder over the last 15 years or so. According to the findings, oxygen levels are dropping in the depths of the oceans, forcing fish to move ever closer to the surface.

Image via Pixabay.

New research from the University of California – Santa Barbara and the University of South Carolina is warning us that fish are slowly drowning. Changes in ecology, as well as the effects of climate change on seasonal patterns, water temperature, and its gradient over different depths, have been causing deeper layers of the ocean to lose their dissolved oxygen content. This, in turn, is forcing fish to either move closer to the surface, or asphyxiate.

It may seem like a trivial matter, but this shift is causing wide-scale changes in marine ecosystems and could have a very real impact on the health of the ocean as a whole. It also raises important questions for fishery management and conservation efforts, with the authors underscoring the importance of accounting for this shift with policy to avoid further damaging marine ecosystems.

Swimming out of breath

“This study finds that oxygen is declining at all the depths we surveyed: from 50 meters to 350 meters,” said lead author Erin Meyer-Gutbrod, assistant professor at the University of South Carolina, “and so fish seem to be moving up to shallower regions to get to an area where the oxygen is relatively higher.”

The findings are based on 15 years’ worth of recordings, surveys, and measurements. These included measurements of dissolved oxygen in samples of water taken at varying depths, of temperature, salinity, and surveys of the average depth at which certain fish species tend to congregate. A total of 60 different species of fish were encountered often enough during these 15 years to be statistically relevant and included in the study.

Data was collected on a yearly basis, every fall, from 1995 through to 2009. The team focused on three reef features between the Anacapa and Santa Cruz islands in Southern California. These were the Anacapa Passage area, with an average depth of 50m, a seamount known as the “Footprint”, at around 150m, and the “Piggy Bank”, with an average depth of around 300m. During the surveys, the team identified all fish species that came within two meters of the submarine or were visible and within two meters of the seafloor. They also estimated the length of each individual fish.

During this time, they saw depth changes in 23 species. Four of these shifted towards deeper waters, while the other 19 moved towards the surface in response to low oxygen conditions (as shown by analysis of water samples).

The team explains that surface waters tend to be better oxygenated (have higher levels of dissolved oxygen) due to surface motions such as waves continuously mixing gases into the top layer of bodies of water. Over time, as waters mix, this oxygen also finds its way lower along the column of water. However, the team explains that warming climates make for warmer surface waters, which increases the buoyancy of these layers compared to those deeper down, reducing their ability to mix. This process is known as ocean stratification.

In addition to this, warmer water has a lower ability to dissolve and hold oxygen compared to colder water, so there’s less of this gas being mixed into the ocean to begin with.

In the end, this means less oxygen makes it to the bottom layers of water. Although salinity and temperature gradients along the column of water also influence the extent of vertical mixing, the team reports that both remained relatively constant over the study period. In other words, the trend towards lower oxygen levels seen at the study site is primarily driven by climate-associated changes in surface water temperatures. That being said, the other factors can’t be discounted completely either.

“A third of [the 60 fish species’] distributions moved shallower over time,” Meyer-Gutbrod said. “I personally think that’s a remarkable result over such a short time period.”

The team acknowledges that their study only included a relatively small area, but it did include a wide range of depths, which was the ultimate objective of the research. This narrower area actually helps reduce confounding factors, they explain, since it allowed for most conditions (apart from depth) to be constant across all the survey areas.

“Other scientists have used lab experiments to show that fish don’t like low oxygen water,” Meyer-Gutbrod said, “but what nobody’s ever done is just return to the same location year after year to see if there’s actually a change in the distribution of fish stemming from a change in oxygen over time.”

In closing, the authors explain that this trend can have quite severe negative impacts on marine ecosystems, and indirectly, on all life on Earth. Fish are simply forced to move away from their optimal depths, which will eventually result in them being pushed out entirely out of several ecosystems. According to co-author Milton Love, a researcher at UC Santa Barbara’s Marine Science Institute, we could even see a point in which species are forced into depth ranges that they simply cannot survive in.

They also cite previous research showing that many fish species also cannot tolerate high water temperatures, and are migrating towards lower depths. In the end, these factors can leave many species in an impossible situation — where they cannot breathe if too low, and can’t bear the heat if too close to the surface.

In the end, even if we start working to redress climate change right now, meaningful progress will take quite a lot of time. Until then, policymakers need to recognize and react to the pressures faced by fish species and issue regulation that protects them as best as possible, or risk wide-ranging ecological collapse in the world’s oceans.

“If you throw your net in the water and you get a ton of fish — more than you’re used to getting — you may think, ‘Oh, it’s a good year for the fish. Maybe the population is recovering,'” Meyer-Gutbrod said. “But instead, it could be that all the fish are just squished into a tighter area. So you could have fishery regulations changing to increase fish allowances because of this increase in landings.”

The paper “Moving on up: Vertical distribution shifts in rocky reef fish species during climate‐driven decline in dissolved oxygen from 1995 to 2009” has been published in the journal Global Change Biology.

Submersible robots help us better understand ocean health and carbon flows

Floating robots could become indispensable in helping us monitor the health of ocean ecosystems and the flow of carbon between the atmosphere and oceans, according to a new study.

Although the microscopic marine plants and animals which make up plankton are the bedrock of ocean ecosystems. While they’re essential for the well-being of everything that swims, they’re also very important for our comfort and well-being, too. Plankton is one of the largest single sources of oxygen on the planet, and it consumes a lot of CO2 to do it. This process is known as marine primary productivity.

Knowing how they’re faring, then, would be a great help. Floating robots can help us out in that regard, according to a new paper.

Floats my boats

“Based on imperfect computer models, we’ve predicted primary production by marine phytoplankton will decrease in a warmer ocean, but we didn’t have a way to make global-scale measurements to verify models. Now we do,” said Monterey Bay Aquarium Research Institute (MBARI) Senior Scientist Ken Johnson, first author of the paper.

Together with former MBARI postdoctoral fellow Mariana Bif, Johnson shows how a fleet of marine robots could completely change our understanding of primary productivity on a global scale. Data from these crafts would allow researchers to more accurately model the flow of carbon between the atmosphere and the ocean, thus improving our understanding of the global carbon cycle.

Furthermore, the duo explains, shifts in phytoplankton productivity can have significant effects on all life on Earth by changing how much carbon oceans absorb, and by altering oceanic food webs. The latter can easily impact human food security, as the oceans are a prime source of food for communities all over the world. In the context of our changing climate, it’s especially important to know with accuracy how much carbon plankton can scrub out of the atmosphere, and what factors influence this quantity.

Part of what makes the ocean such a good carbon sink is that dead organic matter sinks to the bottom. Plankton grows by consuming atmospheric oxygen, and is in turn consumed by other organisms, such as fish. As these eventually die, they sink to the bottom of the sea, where they’re decomposed by bacteria, releasing carbon in the process. However, because this happens at great depths, the carbon is effectively prevented from returning to the atmosphere for very long periods of time. Generally, it seeps into deep-water sediments and stays there for millions of years or more.

That being said, this process is very sensitive to environmental factors such as changes in climate. While we understand that this happens, we’ve not been able to actually monitor how primary productivity is responding to climate change on a global scale, as most of it happens in the depths of the oceans.

“We might expect global primary productivity to change with a warming climate,” explained Johnson. “It might go up in some places, down in others, but we don’t have a good grip on how those will balance.”

“Satellites can be used to make global maps of primary productivity, but the values are based on models and aren’t direct measurements,”

Autonomous robots could help us get the data we need, the study argues. For starters, it’s much easier to build robots that can withstand the humongous pressures of the deep ocean than it is to build equivalent manned submarines. Secondly, robots are mass-producible for relatively little cost. Human crews are expensive and slow to train — they’re also quite limited in availability. Finally, robots can operate for much longer periods of time than human crews, and nobody needs to risk their life in the process.

The authors point to the deployment of Biogeochemical-Argo (BGC-Argo) floats across the globe as a great example of how robots can help monitor primary productivity. These automated floats can measure temperature, salinity, oxygen, pH, chlorophyll, and nutrient content in marine environments, at depths of up to 2,000 meters (6,600 ft). A float can perform its monitoring tasks autonomously, shifting between different depths and supplying live data to researchers onshore. These robots have been deployed in increasing numbers over the past decade, providing reliable — but as of yet, still sparse — measurements of oxygen production across the globe.

Although the data they’ve been feeding us didn’t tell us anything new, it is the first time we’ve been able to quantitatively measure primary productivity directly.

“Oxygen goes up in the day due to photosynthesis, down at night due to respiration—if you can get the daily cycle of oxygen, you have a measurement of primary productivity,” explained Johnson.

In order to confirm that these robots were actually performing their job reliably, the team compared primary productivity estimates computed from the BGC-Argo floats to ship-based sampling data in two regions: the Hawaii Ocean Time-series (HOT) Station and the Bermuda Atlantic Time-series Station (BATS). The data from these two sources matched over several years, proving the reliability of the system.

“We can’t yet say if there is change in ocean primary productivity because our time series is too short,” cautioned Bif. “But it establishes a current baseline from which we might detect future change. We hope that our estimates will be incorporated into models, including those used for satellites, to improve their performance.”

Seeing as we have drones flying about the atmosphere taking pictures of everything and anything, it only makes sense that we’d eventually have some doing the same underwater. I am personally very thrilled to see robots taking on the deepest depths. The ocean is a fascinating place, but I’m also terrified of drowning, so I’ll probably never work up the courage to actually explore it. Hopefully, our automated friends will do the work for us and help us understand what is still a very much unexplored frontier of Earth.

The paper “Constraint on net primary productivity of the global ocean by Argo oxygen measurements” has been published in the journal Nature.

Earth’s rotational slowdown may have led to life as we know it

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

We don’t pay too much attention to it, but every whiff of air is a blessing — and we have bacteria to thank. Whilst Earth is a paradise home to countless species of plants and animals, early in its history, our planet looked radically different, with an atmosphere rich in hydrogen sulfide, methane, and ten to 200 times as much carbon dioxide as today’s atmosphere.

Eventually, Earth’s atmosphere transitioned to an oxygen-rich environment conducive to the evolution of complex and diverse life thanks to photosynthetic cyanobacteria. However, this was an arduous and painfully slow process that unfolded over a period of two billion years. Scientists have always struggled to explain why the oxygenation of Earth’s atmosphere took so long.

Now, an international team of researchers has come a step closer to solving this puzzle. In a new study published today in the journal Nature Geoscience, scientists at the University of Michigan, Grand Valley State University, and the Max Planck Institute for Marine Microbiology have proposed a novel model that explains the slow buildup of oxygen content in the atmosphere, linking cyanobacteria oxygenation with a slowdown in Earth’s rotation.

Late rising cyanobacteria

Map of the Great Lakes basin showing the geological context. Arrow and red circle indicate the location of several submerged Lake Huron sinkholes, including the Middle Island Sinkhole. Image credits: Figure from Biddanda et al. 2012, published in Nature Education Knowledge, and originally sourced from Granneman et al. 2000.

Some of the oldest evidence of life on Earth is 3.5-billion-year-old fossilized remains of microbial mat structures, which look like wrinkle marks in rocks, found in Western Australia. These may have very well been cyanobacteria, also known as blue-green algae. Despite their alternative moniker, cyanobacteria are not actually algae, but rather prokaryotic life forms.

These hardy creatures thrive in hot, cold, salty, acidic, and alkaline environments in which most eukaryotes (organisms with cells that have organelles and distinct nuclei) would perish.

Early cyanobacteria evolved from more primordial organisms and slowly gained the ability to use the sun’s energy, along with carbon and sulfide compounds, to generate energy. The evolution of cyanobacteria went a step further when they started utilizing water during photosynthesis, releasing oxygen as a byproduct.

But although scientists are quite certain cyanobacteria are responsible for the oxygenation of Earth’s atmosphere and the resulting explosion of life, many enigmas remain as to how exactly this process panned out.

“One of the most enduring questions in the Earth Sciences is how Earth became the oxygen-rich planet that we could evolve on. It is clear that photosynthesis is, and always has been, the only significant source of oxygen on our planet. Oxygenic photosynthesis was ‘invented’ by cyanobacteria, the ancestors of all O2 producing phototrophs that we know today. Despite an early evolution of cyanobacteria (before 2.4 billion years ago), Earth only slowly transformed from a reduced harsh environment to the O2 rich planet that we know today. There are many open questions around Earth’s oxygenation pattern. For instance, Why did it take so long after the evolution of oxygenic photosynthesis to reach the first major oxygenation event, the Great Oxidation Event? Why did atmospheric oxygen levels subsequently stay at low levels during the “boring billion” years? What caused the second major rise of oxygen after the boring billion?” geomicrobiologist Judith Klatt of the Max Planck Institute for Marine Microbiology told ZME Science.

The answers to such big questions may have come to Klatt in a flash. Before joining Max Planck, Klat was a postdoc researcher at a lab led by Greg Dick from the University of Michigan. Dick was the leader of an expedition aboard the R/V storm, a 50-foot NOAA research vessel on a mission to collect samples from the Middle Island Sinkhole, several miles offshore from the Michigan town of Alpena.

The water in the Middle Island Sinkhole, found 80-feet-below the water’s surface of Lake Huron, is very rich in sulfur and low in oxygen, conditions that prevailed on Earth billions of years ago.

“This ecosystem thus represents a window into Earth’s past. It, therefore, had been studied already for many years as an analog to the ancient ‘matworld,'” Klatt said.

The mat dance

Geomicrobiologist Judith Klatt, formerly a postdoctoral researcher in Greg Dick’s U-M laboratory and now at the Max Planck Institute for Marine Microbiology, scrapes a microbial mat from the top of a sediment core collected at the Middle Island Sinkhole in Lake Huron. Photo credit: Jim Erickson, University of Michigan News.

Middle Island Sinkhole (MIS) is inhabited by brightly colored bacteria that thrive where most other creatures would have been doomed. Two types of microbes particularly stand out:  purple oxygen-producing cyanobacteria that compete with white sulfur-oxidizing bacteria. The former generates oxygen using sunlight, while the latter eats sulfur for energy.

These microbes have learned to coexist by performing a dance that is repeated and unfolds over the course of each day. From dusk to dawn, the sulfur-consuming bacteria form a mat that sits on top of the cyanobacteria, blocking their access to sunlight. When the sun comes out, the sulfur-eating bacteria descends, making room for the cyanobacteria to rise to the surface and start producing oxygen. However, the cyanobacteria are late risers, taking a few hours before their oxygen production is ramped to the max, Klatt and colleagues learned after performing controlled experiments in Greg Dick’s lab.

“Greg then presented some of these results during a talk for a general audience in 2016. Brian Arbic (a physical oceanographer at the University of Michigan) was present there and then approached us asking if we think that day length would have impacted photosynthesis. While it was clear that MIS mats would have been very sensitive to day length, I was actually hesitant to generalize this thought – despite the stunning similarity between the pattern of oxygenation and Earth rotation rate suggested by some models. It then took more than a year for the next big step. While I was visiting the MPI in Bremen, I suddenly realized that there is in fact a general mechanistic link between day length, i.e. the light dynamics over a day-night cycle, and O2 release from any possible mat. I was super excited, quickly sketched it up, and went over to Arjun Chennu’s desk (who then also worked at the Max Planck Institute for Marine Microbiology and now leads his own group at the Leibniz Centre for Tropical Marine Research (ZMT) in Bremen) to talk it through. He was immediately caught by the idea and we started setting up the numerical model on the very same day. The long journey from tiny to global scales was then a real challenge – but also fun,” Klatt recounted.

Daylight used to be much shorter early in the planet’s history, possibly as short as only six hours. Earth’s rotation rate slowly decreased due to the tug-of-war with the Moon’s gravity and tidal friction. However, this rotational deceleration hasn’t been constant and was even interrupted for about one billion years, which coincides with a long period of static global oxygen levels and stalled biological evolution known as the Boring Billion, a.k.a the Dullest Time in Earth’s History. Earth’s rotational deceleration began again about 600 million years ago, which also marks a major transition in global oxygen concentrations.

To Klatt and colleagues, these coinciding patterns looked more than a simple coincidence. Indeed, the modeling performed by Chennu suggests that day length does, in fact, heavily influence the oxygen release from the cyanobacteria mats.

“After several weeks of modeling, we laid out the oxygen release graphs from two days of different lengths. The difference, while subtle, was there that a longer day releases oxygen differently from a shorter day. We needed much more work to figure out what that means, but I remember that moment when the lines on the graph did not quite align,” Chennu told ZME Science.

These results are somewhat counterintuitive. Although early Earth may have had a 6-hour day, over the span of 24-hours, a surface area would have been exposed to the same amount of cumulative light as today. However, these interruptions caused by early dusk are important owing to molecular diffusion, which is decoupled from oxygen production. In other words, even if the same amount of oxygen is produced by the bacteria during a 24-hour day as during four six-hour days, the net amount of oxygen that is diffused into the atmosphere is much less during the shorter day.

“Even if the mat-cyanobacteria would have produced the very same amount of O2 over billions of years, less O2 would have escaped a mat during a 12 h day compared to an 18-hour day, for instance. These changes might have been relatively small, maybe just a few percent extra oxygen. But considering that Earth was likely a “matworld” these few percent could have had a huge impact. In some extreme cases, including the MIS mats, daylength had, however, a very obvious influence and even turned mats from sinks to sources of oxygen,” Klatt said.

“The heart of our story is simple physics – the physics of diffusional mass transfer, which links the dynamics of light to the export of substances from an ecosystem. When it comes to the question: Could it have mattered sufficiently to shape Earth’s oxygenation pattern?, our story clearly becomes conjectural. We tested our hypothesis as much as possible, but we had to rely on several assumptions, across a wide range of scientific disciplines. Thus, we present a concept rather than a quantitative estimate, which would require more empirical studies,” the researcher added.

Daylight is not the only driver of oxygenation but may have played a crucial role alongside other physical and biological processes, each contributing little but amplifying over time.

“We propose an interaction between planetary mechanics and fine-scale physical and biological processes on extremely small scales over extremely long time scales. The paper is therefore a mosaic of concepts from diverse disciplines. We, therefore, needed to draw from the insights of geology concerning Earth’s oxygenation pattern and from oceanography and astronomy for Earth’s rotational deceleration, for instance. But moving across all kinds of spatial and temporal scales and across fields of research was overall the most fun part,” Klatt concluded.

Another first: NASA’s Perseverance rover extracts oxygen on Mars

The toaster-sized experimental MOXIE instrument aboard the rover extracted oxygen from Martian carbon dioxide. It’s only a proof of concept, but it’s an important one, as it suggests that one day Martian astronauts could make their own oxygen for breathing and rocket fuel.

Technicians in the clean room carefully lowering the Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) instrument into the belly of the Perseverance rover. Credit: NASA/JPL-Caltech

A tree on Mars

The atmosphere of Mars is very different from that of Earth. It’s much thinner (about 96% thinner) and also has a different chemical make-up: it’s poor in oxygen and rich in carbon dioxide. Future astronauts won’t have much use for carbon dioxide, but pure oxygen is a different matter.

“When we send humans to Mars, we will want them to return safely, and to do that they need a rocket to lift off the planet. Liquid oxygen propellant is something we could make there and not have to bring with us. One idea would be to bring an empty oxygen tank and fill it up on Mars,” says Michael Hecht, Principal Investigator of the Perseverance project.

Researchers have been working on ways to do this for a while, and with the Perseverance rover, they got a chance to actually try it out — not in a lab on Earth, but right on Mars.

The MOXIE instrument aims to help humans explore Mars by making OXygen. It works “In situ” (in place) on the Red Planet, and is an Experiment.” As always, NASA loves to toy with acronyms, but the instrument did its job excellently so far.

MOXIE’s first run produced 5.4 grams of oxygen in an hour. The power supply used for the experiment limits potential production to 12 g/hr — about the same amount that a large tree would produce. It’s not spectacular, but it’s the first time this has ever been done, and it could also be scaled up .

“This is a critical first step at converting carbon dioxide to oxygen on Mars,” said Jim Reuter, associate administrator STMD. “MOXIE has more work to do, but the results from this technology demonstration are full of promise as we move toward our goal of one day seeing humans on Mars. Oxygen isn’t just the stuff we breathe. Rocket propellant depends on oxygen, and future explorers will depend on producing propellant on Mars to make the trip home.”

The conversion process requires high levels of heat: 1,470 degrees Fahrenheit (800 Celsius). To withstand these temperatures and carry out the process safely, MOXIE is built from heat-tolerant materials, including 3D-printed nickel alloys and a light aerogel that acts as a buffer, holding the heated air inside. MOXIE is coated with a thin gold layer that reflects infrared heat and ensures that it won’t damage other parts of Perseverance.

Illustration of the MOXIE instrument, depicting the elements within the instrument. Credits: NASA/JPL-Caltech. 

Live off the land

This bodes well for future Mars missions, as transporting oxygen all the way there would be quite a hassle. Oxygen tends to take a lot of space, and it’s very unlikely that astronauts to Mars will be able to carry their own oxygen. Extracting oxygen from the Martian soil or atmosphere will therefore be crucial for future missions.

To get a team of four astronauts off of Mars, a future mission would require about 15,000 pounds (7 metric tons) of rocket fuel and 55,000 pounds (25 metric tons) of oxygen. Astronauts that would carry experiments and potentially spend a lot of time on the Red Planet would also require oxygen (though far less than this). With instruments like MOXIE, they could live off the land — quite literally.

“MOXIE isn’t just the first instrument to produce oxygen on another world,” said Trudy Kortes, director of technology demonstrations within STMD. It’s the first technology of its kind that will help future missions “live off the land,” using elements of another world’s environment, also known as in-situ resource utilization.

“It’s taking regolith, the substance you find on the ground, and putting it through a processing plant, making it into a large structure, or taking carbon dioxide – the bulk of the atmosphere – and converting it into oxygen,” she said. “This process allows us to convert these abundant materials into useable things: propellant, breathable air, or, combined with hydrogen, water.”

Now that the technology demonstration was successful, NASA will attempt to extract oxygen at least nine more times over the next two years (Earthly years, that is). The goal is to test the equipment in different conditions to see if it keeps working properly.

Meanwhile, Perseverance will continue its mission to search for signs of microbial life on Mars, analyzing its geology and past climate, as well as paving the way for human exploration.

Perseverance with science instruments. Image credits: NASA / JPL.

How Mars brine could produce breathable air and fuel for a colony

Our understanding of Mars has been a true rollercoaster. Centuries ago, scholars thought Mars could host rivers and oceans like on Earth and maybe teeming with life. When the first observations came in from Galileo Galilei in 1610, astronomers discovered a planet with polar ice caps that was seemingly similar to Earth, so the hypothesis seemed to stand. But as we learned increasingly more, it became apparent that Mars isn’t exactly a lush planet.

Mars is barren nowadays, and while it may have been water-rich at some point in the past, that’s not really the case now. But there’s one more twist to the story: Mars really does have ice caps, and it does have some liquid water. Granted, that water is full of salts and buried beneath the surface, but it’s still liquid water.

According to a new study, this brine can be used to produce breathable air and fuel for Martian colonists — two valuable resources we would absolutely need on the Red Planet.

Some Martian layers are hiding pockets of water beneath the surface. This water may be used by astronomers to produce breathable air and fuel. Image credits: NASA/MRO.

The rovers we’ve sent to Mars don’t really need oxygen. They do just fine in the ultra-thin atmosphere of the planet, wandering around and doing experiments in freezing temperatures. But if we want to establish a colony (or more likely, a research base), we can’t really manage without oxygen.

In 2008, NASA’s Phoenix Mars Lander came with some good news in that regard. It “tasted” the Martian water and upon analyzing it, found out how it manages to stay liquid on the freezing temperatures of Mars.

The key is something called perchlorate, a chemical compound containing chlorine and oxygen. Perchlorate is very stable in water, and its salts are very solluble — up to the point where they absorb and collect water vapor over time. As the perchlorate absorbs more water, it also dissolves into the water, substantially lowering its freezing temperature — this is how the water manages to remain liquid at temperatures way below the normal freezing point of water.

The European Space Agency’s Mars Express has found several such underground ponds of perchlorate brine and now, a new study reports that these pockets of liquid water could be used to produce valuable resources.

Of course, you can’t drink salty water. You also can’t use it for too many things. If you want to apply the electrolysis to break it down into oxygen (for breathing) and hydrogen (for fuel), you’d normally need to remove the salt — a very costly and complicated process in the harsh Martian environment. This is where the research team led by Vijay Ramani from the University of Connecticut comes in.

Typically, electrolysis requires purified water, but Ramani’s research team found a way to apply electrolysis efficiently to extract hydrogen and oxygen out of the brine simultaneously, without needing to also extract the perchlorate.

“Our Martian brine electrolyzer radically changes the logistical calculus of missions to Mars and beyond” said Ramani. “This technology is equally useful on Earth where it opens up the oceans as a viable oxygen and fuel source”

An outcrop of rocks on the surface of Mars. Image credits: NASA.

They built a modular electrolysis system and tested it at -33 Fahrenheit (-36 Celsius), showing that it really does work. The fact that it’s modular means you can start a small operation on Mars (say, a small research base) and then build on it. Ironically, they were also able to use the salt in their favor.

“Paradoxically, the dissolved perchlorate in the water, so-called impurities, actually help in an environment like that of Mars,” said Shrihari Sankarasubramanian, a research scientist in Ramani’s group and joint first author of the paper.

“They prevent the water from freezing,” he said, “and also improve the performance of the electrolyzer system by lowering the electrical resistance.”

The results are so promising, researchers say, that they’re even considering using a similar technology here on Earth. For instance, submarines or deep-sea could make great use of this technology, potentially enabling us to explore uncharted environments in the deep ocean.

“Having demonstrated these electrolyzers under demanding Martian conditions, we intend to also deploy them under much milder conditions on Earth to utilize brackish or salt water feeds to produce hydrogen and oxygen, for example through seawater electrolysis,” said Pralay Gayen, a postdoctoral research associate in Ramani’s group and also a joint first author on this study.

NASA’s Perseverance rover, currently en-route to Mars, is also carrying some instruments that will allow it to produce oxygen from the Martian brine — but no hydrogen. Perseverance’s equipment is also 25 times less efficient than that designed in Ramani’s lab, but it will be a test for the technology and could perhaps offer new insights on how to apply the technology.

While a Martian base is probably pretty distant possibility, a lunar outpost is almost in sight. NASA has concrete plans to send humans back to the moon in this decade, and it wants to lay down infrastructure for a permanent research base. If this is successful, a Martian base might not be that far off.

The study “Fuel and oxygen harvesting from Martian regolithic brine” was published in PNAS

This company’s weird mission: turning moon dust into oxygen

Humans haven’t been on the moon for about 50 years, since the Apollo Era. But that’s soon about to change. Several ambitious lunar missions are underway, including the Artemis Gateway in orbit, and even planned bases on the surface of the moon, like NASA’s Artemis Base Camp and the ESA’s International Moon Village.

The logistic challenges for establishing a moonbase are enormous. It’s a completely different endeavor from just sending people there and hauling them back. You need infrastructure, food, water, and even air — and you need to produce many of these things using what’s already on the moon.

The bad news is that there’s not that much on the moon. The good news is that even what little is available can be useful. Case in point: a British company has just won a European Space Agency contract to develop the technology that turns moon dust into oxygen, leaving behind useful elements like aluminium and iron.

A proposed design for a lunar base. Image from ESA.

The dust has not settled

The practice of extracting oxygen and metals from lunar dust is simple in principle and very challenging in practice. The main idea is that you take oxidated regolith (which is what lunar dust is called) and break it into pure oxygen and other constituents.

Analyses of this rock showed that oxygen makes about 45% of this dust by weight — encouraging if you want to produce breathing air. But actually extracting it is a very challenging job.

In work published one year ago, researchers at the European Space Agency (ESA), the University of Glasgow, and British company Metalysis, showed that it could be done: up to 96% of the oxygen from lunar soil could be extracted through an electrochemical process developed in 1997 by Cambridge researchers. The process, called the ‘FFC Cambridge process‘, typically takes place at over 900 °C.

Lunar dust before (left) and after (right) the FFC Cambridge process. Image credits: ESA.

The gateway to the solar system

The process is already used here on Earth, but it is typically used as a way to extract metal, with the oxygen being discarded and eliminated as a byproduct. Now, ESA has funded Metalysis for 9 months to tweak the process to also trap and store the oxygen. The oxygen can then be used to produce breathable air, as well as rocket propellant, which could be manufactured on the moon. In addition, the de-oxidized metals will also be useful.

“Anything you take from Earth to the moon is an added weight that you don’t want to carry, so if you can make these materials in situ it saves you a lot of time, effort and money,” said Ian Mellor, the managing director of Metalysis, which is based in Sheffield.

Metalysis will also try to perfect the process and make it ‘moon-proof’, and if it goes according to plan, the next step will be to demonstrate it on the moon. They have 9 months to get to this point.

Mark Symes, one of the researchers working on the process at the University of Glasgow, said moon rock represents “an enormous potential source of oxygen” which could support exploration not only on the moon, but even further in the solar system.

“Oxygen is useful not only for astronauts to breathe, but also as an oxidizer in rocket propulsion systems,” he said. “There is no free oxygen on the moon, so astronauts would have to take all their own oxygen with them to the moon, for life support and to enable their return journey, and this adds considerably to the weight and hence expanse of rocket launches bound for the moon.”

So far, our farthest exploration station has been the International Space Station — which is impressive enough. But building a moon base could serve as a gateway to the rest of the solar system, allowing us to venture even farther away from Earth. For now, the first thing to do is to see how we can produce oxygen on the moon. For now, it all hinges on dust.

Scientists find the first animal that doesn’t breathe oxygen

Aerobic respiration was thought to be ubiquitous in animals, but now scientists have confirmed that this isn’t necessarily the case. A tiny parasite that lives inside the muscles of salmon is the first animal that we know of that doesn’t need to breathe oxygen in order to survive and replicate.

Prof. Hulchon holding a sample of Henneguya salminicola. Credit: Tel Aviv University.

“It is generally thought that during evolution, organisms become more and more complex, and that simple single-celled or few-celled organisms are the ancestors of complex organisms,” Prof. Dorothee Huchon, a life science researcher at Tel Aviv University, said in a statement. “But here, right before us, is an animal whose evolutionary process is the opposite. Living in an oxygen-free environment, it has shed unnecessary genes responsible for aerobic respiration and become an even simpler organism.”

The general assumption has always been that complex multicellular life first appeared on Earth once oxygen levels rose. That’s because aerobic respiration is a major source of energy without which higher-order cellular development cannot take place — or so we thought.

This latest groundbreaking discovery, however, shows that relatively complex organisms can find a way to thrive in strange environments — even when there’s no oxygen to speak of.

Other living organisms such as fungi, bacteria, amoebas and ciliate lineages can also survive in anaerobic environments. The new study shows that this can happen to an animal as well.

“It’s not yet clear to us how the parasite generates energy,” Prof. Huchon says. “It may be drawing it from the surrounding fish cells, or it may have a different type of respiration such as oxygen-free breathing, which typically characterizes anaerobic non-animal organisms.”

The newly discovered parasite, known as Henneguya salminicola, is comprised of fewer than 10 cells and lives inside salmon muscle. The animal, which is classed as a myxozoan, is thought to be a relative of jellyfish and coral.

The cnidarian parasite infecting salmon under a microscope. Image credits: Stephen Atkinson.

Its inability to breathe oxygen was found completely by accident while Huchon and colleagues were sequencing its genome. The researchers were stunned to see that there wasn’t any mitochondrial genome. Mitochondria are known as the powerhouses of the cell. They are organelles that produce energy-rich molecules for the cell. The fact that the animal didn’t have any mitochondria immediately suggested that it doesn’t breathe oxygen.

The new findings, which appeared in the journal PNAS, have important implications for evolutionary research.

“Our discovery confirms that adaptation to an anaerobic environment is not unique to single-celled eukaryotes, but has also evolved in a multicellular, parasitic animal. Hence, H. salminicola provides an opportunity for understanding the evolutionary transition from an aerobic to an exclusive anaerobic metabolism,” the study concludes.

This is the first animal we know that doesn’t breathe

A parasitic creature (distant cousin of the jellyfish) doesn’t have a mitochondrial genome — making it the first multicellular creature we know of that doesn’t need oxygen to survive.

The unseemly parasite features a weird and unique adaptation. Image credits: Stephen Atkinson.

Life is incredibly diverse. From the plant-like corals to the giant mammals and slithering lizards that inhabit the Earth, we’ve found a dazzling variety of creatures. But for all this variety, some things remained unchanged. All life as we know it needs water to survive. It’s all based on carbon — except for some experiments carried out in a lab — and it all needs oxygen. Or so we thought.

The common salmon parasite called Henneguya salminicola is well known to researchers. It causes white cysts that resemble tapioca in the fish muscles, which is why it is also called tapioca disease.

The parasite is a cnidarian belonging to the same phylum as corals, jellyfish and anemones — but it is a distant relative of jellyfish. Henneguya salminicola lives deep inside the fish for its entire lifecycle, which makes for some oxygen-poor conditions.

Researchers have suspected that it must have a special adaptation to allow it to survive when oxygen is scarce, but it wasn’t until Dayana Yahalomi of Tel Aviv University and her colleagues had a thorough look at it that they realized just how weird this adaptation is.

They used deep sequencing and fluorescence microscopy to analyze the parasitic creature, finding that it has completely lost its mitochondrial genome, as well as the capacity for aerobic respiration. Simply put, the creature can’t breathe oxygen.

“Our discovery shows that aerobic respiration, one of the most important metabolic pathways, is not ubiquitous among animals,” the study reads.

Life without oxygen

No oxygen? No problem. At least, if you’re a weird cnidarian parasite infecting salmon. Image credits: Stephen Atkinson.

This is the first macroscopic creature known to not breathe oxygen. This simple trait has been with macroscopic life as we know it, ever since an Archaea swallowed a smaller bacterium, and somehow this worked out for both parties and the two stayed together. That is, the smaller bacteria became an organelle called mitochondria (the fabled powerhouse of the cell), an essential part of the breathing process.

Every cell in your body — and most bodies for that matter — contains large numbers of mitochondria. They break down oxygen to produce a molecule called adenosine triphosphate (ATP), which is then used to power cellular processes. Hence, the powerhouse of the cell thing.

Creatures that live in low-oxygen environments have special adaptations that enable them to survive, but no creature has been observed to completely lack this system.

This raises a number of intriguing questions. For starters where does it get its ATP from? A yet-untested theory is that they somehow leech it from the host, but this is yet to be confirmed. Secondly, how and why did the creature lose its mitochondria?

Researchers suspect that this is a case of genetic simplification, where the parasite simply shed unnecessary, cumbersome DNA as it evolved. This is consistent with the overall evolutionary trend observed in H. salminicola, devolving from a jellyfish-type creature to a much simpler parasite. But the fact that it just shed its mitochondria and ATP synthesis is extreme and very unusual.

Some single-celled creatures have developed mitochondria-type organelles for anaerobic metabolism. But never had this been identified in a multicellular creature — and even whether it was possible at all was debated.

The acquisition of mitochondria was a key step in the evolution of life on Earth. This is a possibility to study life as we didn’t know it before and understand how breathing really works. It’s also a nod that life can sometimes shift in different unexpected directions.

“Our discovery confirms that adaptation to an anaerobic environment is not unique to single-celled eukaryotes, but has also evolved in a multicellular, parasitic animal. Hence, H. salminicola provides an opportunity for understanding the evolutionary transition from an aerobic to an exclusive anaerobic metabolism,” the study concludes.

The study has been published in PNAS.

A new study says oxygen buildup on Earth was “inevitable,” and maybe on other planets, too

While the history of oxygen on Earth is believed to have started with microorganisms or plate tectonics, a new paper reports that this may not be the case.

Image via Pixabay.

The study suggests that the distinct oxygenation events that shaped the Earth’s atmosphere into what it is today may have happened spontaneously, rather than through particularities of our planet (such as biological and tectonic activity). The findings give new insight into the possible history of our planet and offer renewed hope of finding oxygen on alien worlds.

Self-oxygenating?

“Based on this work, it seems that oxygenated planets may be much more common than previously thought, because they do not require multiple — and very unlikely — biological advances, or chance happenings of tectonics,” says study lead author Lewis Alcott, a postgraduate researcher in the School of Earth and Environment at Leeds.

“This research really tests our understanding of how the Earth became oxygen rich, and thus able to support intelligent life.”

Until roughly 2.4 billion years ago, Earth’s atmosphere held no meaningful levels of oxygen. This is due to the gas’s high chemical reactivity — it will bind with almost everything, scrubbing it out of the air. However, that’s when the first of three oxygenation events in our planet’s history occurred.

The first is known as the “Great Oxidation Event”. Subsequent oxygenation events occurred around 800 million years ago and 450 million years ago, leading to the concentrations of atmospheric oxygen of today.

In order to understand how it came to be, the team modified a well-established model of Earth’s marine biogeochemistry to make it run during the entire history of the planet. This model, they report, also produced three different oxygenation events all by itself. This, the team explains, strongly suggests that that beyond early photosynthetic microbes and the initiation of plate tectonics — both of which were established by around three billion years ago — it was simply a matter of time before oxygen would reach the necessary level to support complex life.

While previous research into the appearance of oxygen in Earth’s atmosphere focused on biological revolutions (where life such as algae essentially ‘bioengineers‘ oxygen-rich atmospheres) and tectonic revolutions (the generation of oxygen through volcanic processes), this study highlighted a series of feedback between the global phosphorus, carbon and oxygen cycles. These three together are capable of rapidly shifting ocean and atmospheric oxygen levels without any input from life or tectonics, the team explains. The transitions are driven by the way the marine phosphorus cycle responds to changing oxygen levels, and how this impacts photosynthesis, which requires phosphorus.

The results should bolster our hopes of finding alien planets with oxygen gas present in their atmosphere. While this isn’t a prerequisite for life, it is, to the best of our understanding, essential for the evolution of large, complex organisms — which require a lot of energy.

“Our model suggests that oxygenation of the Earth to a level that can sustain complex life was inevitable, once the microbes that produce oxygen had evolved,” explains study co-author Professor Simon Poulton, also from the School of Earth and Environment at Leeds.

“Our work shows that the relationship between the global phosphorus, carbon and oxygen cycles is fundamental to understanding the oxygenation history of the Earth. This could help us to better understand how a planet other than our own may become habitable,” adds Dr Benjamin Mills, senior author of the study.

The paper “Stepwise Earth oxygenation is an inherent property of global biogeochemical cycling” has been published in the journal Science.

Curiosity rover stumbles upon mystery of oxygen on Mars

NASA scientists have noticed baffling seasonal changes in oxygen on Mars. The concentration of the gas, which many creatures on Earth require in order to breathe, rises and falls with the seasons in a way that scientists cannot yet explain, pointing towards mysterious chemical sources.

A self-portrait taken by NASA’s Curiosity rover taken on Sol 2082 (June 15, 2018). A Martian dust storm has reduced sunlight and visibility at the rover’s location in Gale Crater. Image Credit: NASA/JPL-Caltech/MSSS.

For the past six years that it has been on Mars, the Sample Analysis at Mars (SAM) mobile chemistry lab inside the Curiosity rover, has been sniffing the air above Gale Crater. The analysis confirmed the readings made by other science experiments since the 1970s, finding that the Martian atmosphere is made of 95% CO2, 2.6% nitrogen, 1.9% argon, 0.16% molecular oxygen (O2), and 0.06% carbon monoxide.

These molecules mix together and circulate around the planet due to changes in air pressure throughout the year. According to NASA, these seasonal changes are due to the freezing of CO2 over the poles during winter, which lowers the air pressure across the planet, and the evaporation of CO2 during spring and summer, which raises air pressure as the gas mixes across the Martian atmosphere.

The waxing and waning of CO2 concentrations at Gale Crater are followed by similar changes in nitrogen and argon — so, naturally, scientists thought that oxygen would follow the same curve. For some reason, though, this isn’t happening. Instead, the amount of oxygen in the air rises throughout spring and summer by as much as 30% and then drops back to predictable levels in fall. This pattern repeated each spring, however, the amount of oxygen added to the atmosphere varied — in other words, something must be producing it and something must be removing it.

“The first time we saw that, it was just mind-boggling,” said Sushil Atreya, professor of climate and space sciences at the University of Michigan in Ann Arbor.

What could explain this peculiar pattern? What could be adding oxygen to the atmosphere and what could be subtracting it?

Credit: Melissa Trainer/Dan Gallagher/NASA Goddard.

The SAM instrument itself is well calibrated and the readings are fine, NASA says. Perhaps, CO2 or water might have released the oxygen when the molecules were broken apart in the atmosphere. Later, solar radiation might break the molecular oxygen, leaving two single oxygen atoms free to escape into space. However, this explanation doesn’t stand because there would have to be five times more water than you can find on Mars to produce the extra oxygen and CO2 doesn’t break apart that fast. Moreover, it would take at least a decade for oxygen to break apart and disappear due to solar radiation.

There’s something out there that might explain this, but the truth is that, for now at least, scientists are left in the dark.

“We’re struggling to explain this,” said Melissa Trainer, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland who led this research. “The fact that the oxygen behavior isn’t perfectly repeatable every season makes us think that it’s not an issue that has to do with atmospheric dynamics. It has to be some chemical source and sink that we can’t yet account for.”

The explanation might be tied to another mysterious gas on Mars: methane. Since Curiosity arrived on Mars, the rover’s chemical sensors were able to detect methane, albeit in extremely minute quantities of 0.00000004% on average. The methane concentration also rises and falls seasonally, increasing by about 60% during the summer months. What’s more, the methane concentration in the atmosphere also spikes randomly and significantly at times. Again, scientists do not know why this is happening. But, what may be causing the spikes of methane could also be responsible for the skewed oxygen patterns. Sometimes, the two gases appear to fluctuate in tandem, for instance.

“We’re beginning to see this tantalizing correlation between methane and oxygen for a good part of the Mars year,” Atreya said. “I think there’s something to it. I just don’t have the answers yet. Nobody does.”

On Earth, oxygen and methane can both be produced by organisms but NASA says that on Mars their source isn’t likely to be biological. Instead, the gases are likely produced by chemical processes related to water and rock. One possible source for the extra springtime oxygen is the Martian soil, which contains hydrogen peroxide and perchlorates. Heat and humidity might release oxygen from the soil.

“We have not been able to come up with one process yet that produces the amount of oxygen we need, but we think it has to be something in the surface soil that changes seasonally because there aren’t enough available oxygen atoms in the atmosphere to create the behavior we see,” said Timothy McConnochie, assistant research scientist at the University of Maryland in College Park and another co-author of the paper.

The findings appeared in the Journal of Geophysical Research: Planets.

The best fossils may need oxygen — just a little — to form

We may have had a few bad assumptions about how fossils form, a new study suggests.

Image credits Aryok Mateus.

The prevailing wisdom among paleontologists today is that fossils form in the absence of oxygen. It isn’t a simple guess: some of the best-preserved fossils ever found formed in oxygen-poor conditions in ancient oceans.

However, new research from the University of Texas at Austin found that this assumption wasn’t wrong, but rather incomplete. Fossil formation is jump started in anoxic (‘without oxygen’) conditions, but oxygen is eventually required to complete the process.

Not too little, not too much

“The traditional thinking about these exceptionally preserved fossil sites is wrong,” said lead author Drew Muscente. “It is not the absence of oxygen that allows them to be preserved and fossilized. It is the presence of oxygen under the right circumstances.”

The best-preserved fossils tend to come from Lagerstätte (German for ‘storage place’), rare sedimentary deposits that make up an anoxic, relatively bacteria-free environment. The unique conditions in Lagerstätten support tissue conservation. Fossils in these structures can even preserve soft tissues like flesh or fur alongside hard tissues like bone. This makes them a unique (and uniquely valuable) window into ancient ecosystems.

The new paper examined the fossilization processes at an exceptional fossil site (Ya Ha Tinda Ranch in Canada’s Banff National Park). The site is known for its unique collection of delicate marine life from the Early Jurassic trapped in slabs of black shale. Lobsters have been found in very good condition here, as well as some vampire squids with ink sacks still intact, the team explains.

At the time these animals died (about 183 million years ago), the world’s ocean water had lower levels of oxygen than it does today, consistent with our understanding of fossilization processes. In order to determine whether the fossils started forming in an oxygen-deprived environment, the team analyzed their mineral makeup using a scanning electron microscope (different minerals form in different chemical conditions).

“When you look at lagerstätten, what’s so interesting about them is everybody is there,” said Jackson School undergraduate Brooke Bogan, paper co-author. “You get a more complete picture of the animal and the environment, and those living in it.”

“The cool thing about this work is that we can now understand the modes of formation of these different minerals as this organism fossilizes,” adds Rowan Martindale, Jackson School Assistant Professor and co-author. “A particular pathway can tell you about the oxygen conditions.”

The vast majority of the fossils analyzed were formed of apatite, a phosphate-based mineral. Most importantly, however, we know that apatite needs oxygen to form — so the fossils were at some point in their formation exposed to this gas. Factor in that animals need oxygen to live, and it becomes pretty obvious that at least some of it was floating around dissolved in the ancient ocean water. That being said, however, the team also found that the climatic conditions of a low-oxygen environment helped set the stage for fossilization once oxygen became available.

Periods of low ocean oxygen are linked to high global mean temperatures, which causes sea levels to rise (yes, what we’re causing today). Higher seas come into contact with fresh rocks on the coast and start eroding them, which generates a large influx of phosphate. But, if this low-oxygen state persists, this phosphate simply escapes the sediment (created by rock erosion) and dissolves into the water. The team explains that oxygen is needed to fix this phosphate in sediment, where it can take part in fossilization processes. Muscente said that the apatite fossils of Ya Ha Tinda point to this mechanism.

The researchers plan to continue their work by analyzing specimens from exceptional fossil sites in Germany and the United Kingdom that were preserved around the same time as the Ya Ha Tinda specimens and compare their fossilization histories.

The paper “Taphonomy of the lower Jurassic Konservat-Lagerstätte at Ya Ha Tinda (Alberta, Canada) and its significance for exceptional fossil preservation during oceanic anoxic events” has been published in the journal PALAIOS.

Lunar dirt can be broken down into oxygen and metals

New research from the University of Glasgow is working out how to squeeze metal and oxygen from dry rock; dry moon rocks that is.

Image credits Beth Lomax, University of Glasgow.

Samples of regolith (dirt) retrieved from the Moon revealed that the material is made up of between 40% to 45% oxygen by weight. Essentially, this vital (for us) gas is the single most abundant element in the lunar soil. A group of researchers plans to draw the oxygen out of the dirt, in order to give astronauts and colonists a reliable and plentiful source of breathable air and metals.

Rise from the dirt

“This oxygen is an extremely valuable resource, but it is chemically bound in the material as oxides in the form of minerals or glass, and is therefore unavailable for immediate use,” explains researcher Beth Lomax of the University of Glasgow, whose Ph.D. work is being supported through the European Space Agency’s (ESA) Networking and Partnering Initiative.

The approach involves the use of molten salt electrolysis to pry apart the Oxygen and metallic atoms in regolith. The team reports that this is the first “direct powder-to-powder processing of solid lunar regolith simulant” that can extract all the oxygen in such a sample. Alternative methods, they add, either achieve much lower yields or require extreme temperatures (in excess of 1600°C) to work.

The team placed powdered regolith in a mesh-lined basket, mixing in molten calcium chloride salt as an electrolyte. Then they baked everything up to 950°C. While the regolith is still solid at this temperature, the team explains that pushing current through it causes the oxygen atoms to migrate across the molten salt and build-up at the anode.

The technique takes around 50 hours to pull 96% of the oxygen from a sample, but around 75% of the total is extracted in the first 15 hours.

“This research provides a proof-of-concept that we can extract and utilise all the oxygen from lunar regolith, leaving a potentially useful metallic by-product,” adds Lomax.

“This work is based on the FCC process — from the initials of its Cambridge-based inventors — which has been scaled up by a UK company called Metalysis for commercial metal and alloy production.”

Going forward, the team plans to continue cooperating with Metalysis and ESA to ready the process for a lunar context. The process would give lunar settlers access to oxygen for fuel and life support, and raw material (metals) for on-site manufacturing. Exactly what metals they would obtain, the team says, would depend on where on the Moon they land.

Furthermore, the same approach could likely work on Mars as well, materials engineer Advenit Makaya told Phys. The findings also tie in nicely with previous research that developed an approach to extract water out of lunar regolith. Future colonists, it seems, will have ample resources at their disposal.

The paper “Proving the viability of an electrochemical process for the simultaneous extraction of oxygen and production of metal alloys from lunar regolith” has been published in the journal Planetary and Space Science.

Key variable used to study Mars’ ancient atmosphere varies during the day

New research is helping to improve our understanding of how Mars lost its atmosphere — and how much of it the planet lost.

Image via Wikimedia.

A new study led by NASA shows that a key tracer used to estimate how much atmosphere the planet lost changes with the temperature and time of day on Mars. The work should help make sense of previous measurements of the tracer, which have found wildly conflicting results. Having an accurate measurement of this tracer — a particular isotope of the oxygen atom — will enable us to estimate whether Mars has ever been habitable and what it was like on its surface.

The air that was

“We know Mars had more atmosphere. We know it had flowing water. We do not have a good estimate for the conditions apart from that — how Earthlike was the Mars environment? For how long?” said Timothy Livengood of the University of Maryland, College Park and NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who led the study.

Even today, Mars has features such as dry riverbeds and mineral compounds that form in liquid water which point to much milder days in its past. One element that’s critical for such a past is a thick atmosphere that could retain enough heat for water to stay liquid on the surface.

However, Mars has lost all that atmosphere today, which transformed its climate from one that could (potentially) nurture life to the dry and freezing environment found by NASA missions such as MAVEN, Curiosity, and the Viking missions of 1976.

Naturally, researchers have a lot of questions regarding the Red Planet’s ancient atmosphere. One way to estimate its nature and properties is to look at oxygen isotopes — lighter isotopes escape into space faster than light ones, so the remaining atmosphere gets enriched in heavier ones.

In Mars’ case, the lighter (and more common) isotope of oxygen is 16O, while the heavier one is 18O. By analyzing the relative amount of each of these isotopes, researchers can get a good idea of how thick the atmosphere was on early Mars.

The glaring flaw in this approach is that the 18O/16O ratio has been measured several times, producing various readings. The new paper provides a way to resolve this discrepancy by showing that the ratio can change during the Martian day.

“Previous measurements on Mars or from Earth have obtained a variety of different values for the isotope ratio,” said Livengood. “Ours are the first measurements to use a single method in a way that shows the ratio actually varying within a single day, rather than comparisons between independent devices.”

“In our measurements, the isotope ratio varies from being about 9% depleted in heavy isotopes at noon on Mars to being about 8% enriched in heavy isotopes by about 1:30pm compared to the isotope ratios that are normal for Earth oxygen.”

This range of ratios, they explain, is consistent with previously reported measurements. This suggests that those measurements were corrent, but disagreed because the dynamics of the Martian atmosphere are more complex than we assumed.

These ratio changes throughout the day are likely a routine occurrence caused by changes in ground temperature, the team explains. Molecules with heavier isotopes likely stick to cold surface grains at night more than the lighter isotopes which are freed (thermally desorbed) as the surface warms up during the day.

As Mars’ atmosphere is mostly made up of carbon dioxide (CO2), the team studied oxygen isotopes bound up in CO2 molecules. For the observations, they used the Heterodyne Instrument for Planetary Winds and Composition developed at NASA Goddard, currently installed at the NASA Infrared Telescope Facility on Mauna Kea, Hawaii.

“While trying to understand the broad spread in estimated isotope ratios that we retrieved from the observations, we noticed that they were correlated with the surface temperature that we also obtained,” said Livengood. “That was the insight that set us on this path.”

The paper “Evidence for diurnally varying enrichment of heavy oxygen in Mars atmosphere” has been published in the journal Icarus.

Geologists uncover ancient mass extinction from 2 billion years ago

Even before macroscopic life has evolved, Earth’s inhabitants were faced with extinctions of gargantuan proportions.

Image credits: Mike Beauregard/Wikimedia Commons

We’re taught in school about the five mass extinctions. These mass extinctions — which mark the end of geological periods — were described in a landmark paper published in 1982. The “Big Five” extinction events, as they are sometimes referred to, helped us understand that life on Earth is more dynamic and more prone to global disasters than we once thought. But now, a new study shows that mass extinctions have been happening for as long as life has existed on our planet.

Mass extinctions are not easy to define — even when they are macroscopic. When they are microscopic, it gets event more difficult. To find evidence of this even, researchers turned to barite from the Belcher Islands in Hudson Bay, Canada.

Barite is a mineral consisting of barium sulfate that encapsulates a record of oxygen in the atmosphere. It’s not easy to find rocks (let alone a specific mineral) that remained unturned for 2 billion years, but this was possible in Canada’s Belcher islands.

The barite samples revealed that Earth experienced huge changes in its early ecosystems — and 2.05 billion years ago, there was an enormous drop in life coinciding with a drop in oxygen levels.

“This shows that even when biology on Earth is comprised entirely of microbes, you can still have what could be considered an enormous die-off event that otherwise is not recorded in the fossil record,” says geologist Malcolm Hodgskiss from Stanford University, who led the study.

“The fact that this geochemical signature was preserved was very surprising,” Hodgskiss said. “What was especially unusual about these barites is that they clearly had a complex history.”

Long before complex life emerged and diversified, it was a period of feast or famine in Earth’s history. Some 2.4 billion years ago, Earth’s atmospheric oxygen was scarce. But when cyanobacteria entered the scene, they changed the entire system. These microorganisms lived in the Earth’s primordial oceans, which were essentially empty at the time. They thrived and expanded, using sunlight for photosynthesis and eliminating oxygen into the air.

This is called the Great Oxidation Event, and for life on Earth, it was a time of feasting. But, for reasons which are not entirely clear, this period came to an abrupt (and catastrophic) end — and with it, life also recoiled.

The finding also supports the “Oxygen Overshoot” theory, which suggests that the oxygen-releasing microorganisms hit a critical peak and spread more than they should. Without the nutrients to sustain them, they started to dwindle, which led to a decrease in atmospheric oxygen.

“Some of these oxygen estimates likely require too many microorganisms living in the ocean in Earth’s past,” says geochemist Peter Crockford from the Weizmann Institute of Science and Princeton University.

“So we can now start to narrow in on what the composition of the atmosphere could have been through this biological angle.”

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.

Meet the fish that can hold its breath underwater

A Red Coffinfish, Chaunacops coloratus, found off southern Queensland at a depth of 2500 m. Credit: Rob Zugaro / Museums Victoria.

Although they live underwater, just like us, fish need oxygen to survive. Now, scientists have come across an odd sight: a fish that lives on the bottom of the ocean that can “hold its breath” up to 4 minutes at a time.

Oxygen is one of the things our bodies use to make energy. Humans have evolved lungs to take in oxygen from the air and exhale all the other gases that we don’t actually need, with the addition of carbon dioxide which is a byproduct of respiration. Fish had to find a way to extract oxygen from the water — which is where their gills come in. Gills work like filters that collect the oxygen required for a fish to breathe, which is then sent through the blood to fuel the body.

When you breathe, your chest and lower abdomen puff out and flatten as it lets air in and out. Similarly, a fish gets bigger when it breathes in water and smaller when it lets water out. Fish and other animals with gills are able to extract oxygen because their blood flows through the gills in the opposite direction of water, otherwise, the fish would not have been able to get as much as oxygen from it.

Pull a fish out of the water, and it will quickly suffocate because there’s no water to drive oxygen through the gills. Just like you and other terrestrial creatures would die if we’d be underwater for more than a couple minutes. Luckily we can hold our breath… and so can the coffinfish (Chaunax endeavouri), apparently.

Researchers at the National Oceanic and Atmospheric Administration (NOAA) caught this peculiar behavior on camera by accident. They were using one of their remotely operated submersibles in the Atlantic and Pacific oceans when they recorded at least eight individuals holding large quantities of water in their enormous gill chambers. For minutes, there was no sign of inhaling or exhaling. When the coffinfish finally open their gills, their bodies deflate by up to 30%.

According to the authors of a new study published in the Journal of Fish Biology, the coffinfish may be holding its breath to conserve energy which would have otherwise been used to pump water. ” This holding breath behavior has not been observed in any other fishes and is probably highly energetically efficient,” the authors of the study wrote. Alternatively, the bloated size could help ward off predators.

Comet-inspired reactor could create oxygen for astronauts

When it comes to space, oxygen has been famously known to be in short supply. This is why it was a very pleasant surprise when two researchers at the California Institute of Technology found a way to produce some.

Konstantinos P. Giapis with his reactor that converts carbon dioxide to molecular oxygen. Credit: Caltech.

In 2015, the European Space Agency’s Rosetta spacecraft unexpectedly found abundant levels of molecular oxygen in Comet 67Ps atmosphere. Molecular oxygen in space is highly unstable, as oxygen prefers to pair up with hydrogen to make water, or carbon to make carbon dioxide. When oxygen was detected streaming out of the comet, it was believed that the gas had been locked inside the comet for billions of years.

However, in 2017, Caltech researchers proposed that the oxygen was actually created by other compounds slamming into the comet at high speeds. After water or carbon dioxide are discharged from the comet, solar winds accelerate them back into the comet, which creates molecular oxygen.

Now Caltech scientists have created a reactor to reproduce this reaction originally found in outer space. Such technology is appealing, as it could provide future astronauts on Mars a way to generate their own air. It could even be utilized on our home planet to combat our little carbon dioxide problem. The process would remove CO2 from the atmosphere, converting it into O2, giving humans a leg-up in the war against climate change.

It works by crashing CO2 onto the inert surface of gold foil. The foil cannot be oxidized and theoretically should not produce molecular oxygen. However, through the experiment, O2 continued to be emitted from the gold surface. This meant that both atoms of oxygen come from the same CO2 molecule, effectively splitting it in extraordinary style.

“At the time we thought it would be impossible to combine the two oxygen atoms of a CO2 molecule together because CO2 is a linear molecule, and you would have to bend the molecule severely for it to work,” says Konstantinos P. Giapis, a professor of chemical engineering at Caltech. “You’re doing something really drastic to the molecule.”

Credit: Caltech.

Most chemical reactions require energy, which is most often provided as heat. However, Giapis’s research shows some unusual reactions can occur by providing kinetic energy. When water molecules are shot like extremely tiny bullets onto surfaces containing oxygen, such as sand or rust, the water molecule can rip off that oxygen to produce molecular oxygen.

“In general, excited molecules can lead to unusual chemistry, so we started with that,” Tom Miller, a professor of chemistry at Caltech, says. “But, to our surprise, the excited state did not create molecular oxygen. Instead, the molecule decomposed into other products. Ultimately, we found that a severely bent CO2 can also form without exciting the molecule, and that could produce O2.”

The device the Caltech team devised works like a particle accelerator. It converts carbon dioxide molecules into ions by giving them a charge and then fast-tracking them using an electric field, though at drastically lower energies than you’ll find in a particle accelerator. The device generates only one or two oxygen molecules for every 100 carbon dioxide molecules.

“You could throw a stone with enough velocity at some CO2 and achieve the same thing. It would need to be traveling about as fast as a comet or asteroid travels through space,” said Giapis but stresses this is not the final product. “Is it a final device? No. Is it a device that can solve the problem with Mars? No. But it is a device that can do something that is very hard,” he says. “We are doing some crazy things with this reactor.”

The study was published in the journal Nature Communications

The ISS starts experimenting with a photo-bioreactor

As if having a research station in space wasn’t awesome enough — astronauts are now getting a photo-bioreactor which will use algae to produce clean oxygen.

Image credits: IRS Stuttgart/DLR.

As NASA is tentatively considering deep-space exploration, it’s starting to hit one of the hard limitations on this type of project: the human body. Unlike engines, fuel tanks, or other spacecraft components, the human body is very difficult to tweak. It requires a fixed set of resources without which it just cannot do. Air, water, and food are the most important ones, and ensuring this triad in a long-term space shuttle is not easy.

The ISS is constantly re-equipped with supplies but in order for a long-term mission to succeed, we would need a closed-loop system with recycling and reusing resources. In the case of air, the basic system is simple: we already have an excellent mechanism to recycle oxygen in the form of plants. However, while the principle is pretty clear, implementation has proven quite challenging. However, NASA believes it may have found a solution in the form of a photobioreactor.

This German-made experiment has been flown onto the ISS and experimentation has commenced just this week. The system sucks some of the carbon dioxide and a few other gases from the air, producing methane and water from it, the latter of which is then fed back through the system into an electrolysis process that produces oxygen. The oxygen is then recycled into the cabin.

A summary of how the system works. Image credits: IRS Stuttgart/DLR. Click to zoom in.

It’s a clever hybrid system that mixes the algae’s natural chemical abilities with a manmade electrolysis system. This approach works much better than the individual sum of its parts.

“With the first demonstration of the hybrid approach, we are right at the forefront when it comes to the future of life-support systems,” said the exploration and project leader Oliver Angerer in a statement for the German Aerospace Center (DLR).

“Of course, the use of these systems is interesting primarily for planetary base stations or for very long missions. But these technologies will not be available when needed if the foundations are not laid today.”

The key player of this system is Chlorella vulgaris, a green microalgae also used as a protein-rich food additive. The photosynthetic microorganism has a thick cell wall and is overall very resilient, which makes it excellently suited for long-term missions. It only needs light and small amounts of a nutrient solution. In addition, the algae could be consumed for nutrients — something which is not explored in the current experiment but might be possible nonetheless.

For now, the system is not capable of producing sufficient oxygen for the entire ISS crew, but it will serve as a proof-of-concept for larger-scale experiments. Having a self-sustainable oxygen source is crucial for long-term space missions, as well as future base stations on the Moon or on Mars.

Arsenic.

There are arsenic-breathing microbes in the tropical Pacific, a new study finds

Arsenic is generally viewed as a life-ending element, but new research shows how some organisms rely on it to breathe.

Arsenic.

Image credits fdecomite / Flickr.

Certain microorganisms in the Pacific Ocean respire arsenic, according to a new study from the University of Washington. The findings are quite surprising as, although arsenic-based respiration has been documented in ancient and current organisms, it is extremely rare on the planet. Moreover, ocean water just doesn’t have that much arsenic, to begin with.

Doing without

“We’ve known for a long time that there are very low levels of arsenic in the ocean,” said co-author Gabrielle Rocap, a UW professor of oceanography. “But the idea that organisms could be using arsenic to make a living—it’s a whole new metabolism for the open ocean.”

The team analyzed Pacific seawater samples taken from water layers at depth intervals where oxygen is almost absent. Given the lack of oxygen here, organisms had to adapt and seek other sources of energy, the team writes. The results are interesting and may become very important in our understanding of marine ecosystems, as these areas — known as oxygen-deficient zones, ODZs or oxygen minimum zones, OMZs — will likely expand under climate change, according to other recent research.

The most common alternatives to oxygen that biology draws upon today are nitrogen and sulfur. However, previous research carried out by Jaclyn Saunders, this paper’s first author, suggested that arsenic might also do the trick. She was curious to see whether this was the case, which spurred the present paper.

The samples used in this study were collected during a 2012 research cruise to the tropical Pacific, off the coast of Mexico. Analysis of eDNA material recovered from the samples showed two genetic pathways that process arsenic-based molecules to extract energy. Two different forms of arsenic seem to be targeted by these pathways, leading the authors to believe that we’re looking at two organisms that cycle arsenic back and forth between the different forms. Which, as far as ecosystems are concerned, is quite a nifty trick.

“Thinking of arsenic as not just a bad guy, but also as beneficial, has reshaped the way that I view the element,” said Saunders, who did the research for her doctoral thesis at the UW and is now a postdoctoral fellow at the Woods Hole Oceanographic Institution and the Massachusetts Institute of Technology.

While arsenic might be beneficial, it’s certainly not very popular. Only about 1% of the microbe population in the samples seems to breathe arsenic, judging by the ratios of genetic material. Most likely, these strains are loosely-related to arsenic-breathing microbes found in hot springs or contaminated sites on land. Saunders recently collected samples from the same region and is now trying to grow the arsenic-breathing marine microbes in a lab in order to study them more closely.

“Right now we’ve got bits and pieces of their genomes, just enough to say that yes, they’re doing this arsenic transformation,” Rocap said. “The next step would be to put together a whole genome and find out what else they can do, and how that organism fits into the environment.”

“What I think is the coolest thing about these arsenic-respiring microbes existing today in the ocean is that they are expressing the genes for it in an environment that is fairly low in arsenic,” Saunders said. “It opens up the boundaries for where we could look for organisms that are respiring arsenic, in other arsenic-poor environments.”

Arsenic respiration is most likely a ‘retro’ type of respiration, passed down over the eons. When life first sprung up on Earth, oxygen was very scarce both in the air and in the ocean (as oxygen is very reactive and forms chemical bonds readily). Until photosynthesizing plants became widespread, there simply wasn’t enough output of this gas to maintain any meaningful levels available for organisms to use up. As such, early life had to use something else for energy — and arsenic was likely common in the oceans at that time.

Climate change may, sadly, breathe new life into arsenic-breathing life. Low-oxygen regions are projected to expand as thermal imbalances shift water currents, and dissolved oxygen is also predicted to drop across the board in marine environments.

The paper “Complete arsenic-based respiratory cycle in the marine microbial communities of pelagic oxygen-deficient zones” has been published in the journal Proceedings of the National Academy of Sciences.

Moon.

The European Space Agency wants to mine the moon for oxygen and water

I think we have some of those down here already!

Moon.

Image credits Robert Karkowski.

The ESA just signed a one-year contract with Europe’s largest launch services provider, ArianeGroup, to study the feasibility of mining on the moon. Should everything go according to plan, ESA wants to launch the mission by 2025, the Popular Mechanics reports.

Moondust

The mission would focus on the lunar regolith, the dust-like soil covering our moon. It’s not exactly what we’d call ‘soil’ back here — on Earth, soils contain quite a lot of organic matter. Regolith, however, does contain molecular oxygen and water. It’s also quite rich in helium-3 isotopes, which “could provide safer nuclear energy in a fusion reactor, since it is not radioactive and would not produce dangerous waste products,” according to the ESA.

[This study is] “an opportunity to recall the ability of Ariane 64 to carry out Moon missions for its institutional customers, with a payload capacity of up to 8.5 metric tons,” says André-Hubert Roussel, CEO of ArianeGroup.

“In this year, marking the fiftieth anniversary of Man’s first steps on the Moon, ArianeGroup will thus support all current and future European projects, in line with its mission to guarantee independent, sovereign access to space for Europe.”

The mission would launch on an Ariane 64 rocket. The vehicle is still in the works and is a variation of the company’s Ariane 6 rocket with an extra four strap-on boosters. Berlin-based PTScientists, a former Google Lunar XPrize competitor, will also be involved in the study. ArianeGroup will handle the rocket and PTScientists will design and build the lander to actually touch-down on the moon.

“We are very pleased with the confidence placed in us by the European Space Agency,” said Robert Boehme, CEO and founder of PTScientists, in a press statement.

While the mission is being evaluated and the hardware is being set-up, ESA spacewalk instructor Hervé Stevenin and ESA astronaut Matthias Maurer are working together with geologists and engineers to simulate a lunar spacewalk in the desolate volcanic area of Lanzarote, Spain as part of Pangaea-X. This is a test campaign that set up by ESA to pool together expertise on space exploration, high-tech survey equipment, and geology meant to train the crewmembers of this future mission.

Spacesuits are bulky, uncomfortable things. They also limit an astronaut’s range of motions by quite a large margin. You can’t kneel down or bend over in a pressurized suit in space, the gloves make it hard to handle anything, arm movement is restricted by the suit’s articulated joints, and the helmet limits the field of view. The astronauts training with Hervé are testing operation concepts and equipment prototypes designed to take into account this limited range of movement they’ll experience in a suit. Their current training will make them feel at ease once they set foot on the moon.

“We do not have a lunar spacesuit for these tests, but after spending many hours training with NASA’s spacesuits we are accustomed to the limitations of mobility. We applied this knowledge – and our body memory – to testing the lunar tools,” says Hervé.

The spacewalkers’ gear was outfitted with video cameras that transmitted live feeds to the scientists. Wide angle videos, 360 panoramas, close-ups, and microscopic images were sent to the ‘spacewalk coordinator’ and other scientists monitoring the simulated mission from mission control.

“The next generation of lunar explorers will be trained in relevant scientific disciplines, but there will always be more expertise on Earth,” says Samuel Payler, research fellow at the European Astronaut Centre in Cologne, Germany.

“The challenge is to have this expertise transmitted to the astronauts during a moonwalk to make the best decisions based on science. Sharing data in real time, including images and video, is an essential part of this.”