Extreme Life Archives

April 11, 2010December 24, 2015 by Nancy Atkinson

Life on Titan Could Be Smelly and Explosive

Artist concept of Methane-Ethane lakes on Titan (Credit: Copyright 2008 Karl Kofoed). Click for larger version.

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Could there be life on Titan? If so, one astrobiologist says humans probably couldn’t be in the same room with a Titanian and live to tell about it. “Hollywood would have problems with these aliens” said Dr. William Bains. “Beam one onto the Starship Enterprise and it would boil and then burst into flames, and the fumes would kill everyone in range. Even a tiny whiff of its breath would smell unbelievably horrible. But I think it is all the more interesting for that reason. Wouldn’t it be sad if the most alien things we found in the galaxy were just like us, but blue and with tails?”

While giving an obvious nod to the recent movie “Avatar,” Bains’ research provides insight to the difficulties we might encounter – beyond cultural – if we ever meet up with alien life. There could be unintended harmful consequences for one species, or both.

Bains is working to find out just how extreme the chemistry of life can be. Life on Titan, Saturn’s largest moon, represents one of the more bizarre scenarios being studied. While images sent back by the Cassini/Huygens mission might make Titan look Earth-like and maybe even inviting, it has a thick atmosphere of frozen, orange smog. At ten times our distance from the Sun, it is a frigid place, with a surface temperature of -180 degrees Celsius. Water is permanently frozen into ice and the only liquid available is liquid methane and ethane.

So instead of water based-life (like us), life on Titan would likely be based on methane.

“Life needs a liquid; even the driest desert plant on Earth needs water for its metabolism to work. So, if life were to exist on Titan, it must have blood based on liquid methane, not water. That means its whole chemistry is radically different. The molecules must be made of a wider variety of elements than we use, but put together in smaller molecules. It would also be much more chemically reactive,” said Bains.

Additionally, Bains said a metabolism running in liquid methane would have to be built of smaller molecules than terrestrial biochemistry.

“Terrestrial life uses about 700 molecules, but to find the right 700 there is reason to suppose that you need to be able to make 10 million or more,” Bains said. “The issue is not how many molecules you can make, but whether you can make the collection you need to assemble a metabolism.”

Bains said doing such assembling is like trying to find bits of wood in a lumber-yard to make a table.

“In theory you only need 5,” he said. “But you may have a lumber-yard full of offcuts and still not find exactly the right five that fit together. So you need the potential to make many more molecules than you actually need. Thus the 6-atom chemicals on Titan would have to include much more diverse bond types and probably more diverse elements, including sulphur and phosphorus in much more diverse and (to us) unstable forms, and other elements such as silicon.”

Energy is another factor that would affect the type of life that could evolve on Titan. With Sunlight a tenth of a percent as intense on Titan’s surface as on the surface of Earth, energy is likely to be in short supply.

“Rapid movement or growth needs a lot of energy, so slow-growing, lichen-like organisms are possible in theory, but velociraptors are pretty much ruled out,” said Bains.

Whatever life may be on Titan, at least we know there won’t be a Jurassic Park.

Bains, whose research is carried out through Rufus Scientific in Cambridge, UK, and MIT in the USA, is presenting his research at the National Astronomy Meeting in Glasgow, Scotland on April 13, 2010.

Source: RAS NAM

December 16, 2009December 24, 2015 by Nancy Atkinson

Astronomers Find Super-Earth With An Atmosphere

This artist’s conception shows the newly discovered super-Earth GJ 1214b, which orbits a red dwarf star 40 light-years from our Earth. Credit: Credit: David A. Aguilar, CfA

More exoplanets this week! Today astronomers announced the discovery of so called super-Earth around a nearby, low-mass star, GJ1214. The newly discovered planet has a mass about six times that of Earth and 2.7 times its radius, falling in between the size of Earth and the ice giants of the Solar System, Uranus and Neptune. But this latest exoplanet, GJ1214b, has something else, too: an atmosphere about 200 km thick. “This atmosphere is much thicker than that of the Earth, so the high pressure and absence of light would rule out life as we know it,” said David Charbonneau, lead author of a paper in Nature reporting the discovery, “but these conditions are still very interesting, as they could allow for some complex chemistry to take place.”

GJ1214b is also a very hot place to be. It orbits its star once every 38 hours at a distance of only two million kilometres — 70 times closer to its star than the Earth is to the Sun. “Being so close to its host star, the planet must have a surface temperature of about 200 degrees Celsius, too hot for water to be liquid,” said Charbonneau.

However, another member of the team said water ice could possibly be present on GJ1214b, deep inside the heart of the planet. “Despite its hot temperature, this appears to be a waterworld,” said graduate Zachory Berta who first spotted the hint of the planet among the data. “It is much smaller, cooler, and more Earth-like than any other known exoplanet.”

The star is a small, red type M star about one-fifth the size of our Sun. It has a surface temperature of only about 2,700 C (4,900 degrees F) and a luminosity only three-thousandths as bright as the Sun.

Artist impression of how the newly discovered super-Earth surrounding the nearby star GJ1214 may look. Credit: ESO/L. Calçada

Charbonneau compared this new exoplanet to Corot-7b, the first rocky super-Earth found using the transit method, when the planet’s orbit is takes it across the face of its parent star, from our vantage point. .
The astronomers were also able to obtain the mass and radius of GJ1214b, allowing them to determine the density and to infer the inner structure.

Although the mass of GJ1214b is similar to that of Corot-7b, its radius is much larger, suggesting that the composition of the two planets must be quite different. While Corot-7b probably has a rocky core and may be covered with lava, astronomers believe that three quarters of GJ1214b is composed of water ice, the rest being made of silicon and iron.

“The differences in composition between these two planets are relevant to the quest for habitable worlds,” said Charbonneau. “If super-Earth planets in general are surrounded by an atmosphere similar to that of GJ1214b, they may well be inhospitable to the development of life as we know it on our own planet.”

The atmosphere was detected when the astronomers compared the measured radius of GJ1214b with theoretical models of planets. They found that the observed radius exceeds the models’ predictions, and deduced that a thick atmosphere was blocking the star’s light.

“Because the planet is too hot to have kept an atmosphere for long, GJ1214b represents the first opportunity to study a newly formed atmosphere enshrouding a world orbiting another star,” said Xavier Bonfils, another member of the team. “Because the planet is so close to us, it will be possible to study its atmosphere even with current facilities.”

The planet was first discovered as a transiting object within the MEarth project, which follows about 2000 low-mass stars to look for transits by exoplanets, and uses a fleet of eight small, (16-inch) amateur-sized ground-based telescopes.

To confirm the planetary nature of GJ1214b and to obtain its mass (using the so-called Doppler method), the astronomers needed the full precision of the HARPS spectrograph, attached to ESO’s 3.6-metre telescope at La Silla.

The next step for astronomers is to try to directly detect and characterize the atmosphere, which will require a space-based instrument like NASA’s Hubble Space Telescope. GJ1214b is only 40 light-years from Earth, within the reach of current observatories.

Source: ESO, CFA

October 30, 2009December 24, 2015 by Nicholos Wethington

Bacteria Could Survive in Martian Soil

Certain strains of bacteria, including Bacilus Pumilus, may be able to survive on the Martian surface. Image credit: NASA

Multiple missions have been sent to Mars with the hopes of testing the surface of the planet for life – or the conditions that could create life – on the Red Planet. The question of whether life in the form of bacteria (or something even more exotic!) exists on Mars is hotly debated, and still requires a resolute yes or no. Experiments done right here on Earth that simulate the conditions on Mars and their effects on terrestrial bacteria show that it is entirely possible for certain strains of bacteria to weather the harsh environment of Mars.

A team led by Giuseppe Galletta of the Department of Astronomy at the University of Padova simulated the conditions present on Mars, and then introduced several strains of bacteria into the simulator to record their survival rate. The simulator – named LISA (Laboratorio Italiano Simulazione Ambienti) – reproduced surface conditions on Mars, with temperatures ranging from +23 to -80 degrees Celsius (73 to -112 Fahrenheit), a 95% CO2 atmosphere at low pressures of 6 to 9 millibars, and very strong ultraviolet radiation. The results – some of the strains of bacteria were shown to survive up to 28 hours under these conditions, an amazing feat given that there is nowhere on the surface of the Earth where the temperatures get this low or the ultraviolet radiation is as strong as on Mars.

Two of the strains of bacteria tested – Bacillus pumilus and Bacillus Nealsonii – are both commonly used in laboratory tests of extreme environmental factors and their effects on bacteria because of their ability to produce endospores when stressed. Endospores are internal structures of the bacteria that encapsulate the DNA and part of the cytoplasm in a thick wall, to prevent the DNA from being damaged.

Galletta’s team found that the vegetative cells of the bacteria died after only a few minutes, due to the low water content and high UV radiation. The endospores, however, were able to survive between 4 and 28 hours, even when exposed directly to the UV light. The researchers simulated the dusty surface of Mars by blowing volcanic ash or dust of red iron oxide on the samples. When covered with the dust, the samples showed an even higher percentage of survival, meaning that it’s possible for a hardy bacterial strain to survive underneath the surface of the soil for very long periods of time. The deeper underneath the soil an organism is, the more hospitable the conditions become; water content increases, and the UV radiation is absorbed from the soil above.

Given these findings, and all of the rich data that came in last year from the Phoenix lander – especially the discovery of perchlorates – continuing the search for life on Mars still seems a plausible endeavor.

Though this surely isn’t a confirmation of life on Mars, it shows that even life that isn’t adapted to the conditions of the planet could potentially hold out against the extreme nature of the environment there, and bodes well for the possibility of Martian bacterial life forms. The LISA simulations also indicate the importance of avoiding cross-contamination of bacteria from Earth to Mars on any scientific missions that travel to the planet. In other words, when we finally are able to definitively test for life on our neighboring planet, we don’t want to find out that our Earth bacteria have killed off all the native lifeforms!

Sources: Arxiv papers here and here.

May 21, 2009December 24, 2015 by Nancy Atkinson

With Moon Rocks in Hand, Parazynski Reaches Mt. Everest Peak

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We’ve been following former astronaut Scott Parazynski’s attempt to climb Mt. Everest, and now comes the news that he has successfully reached the summit, one year after a back injury forced him to give up his climb. “It was a wonderful experience, though and through,” Parazynski said in a Skype interview with Miles O’Brien, “and certainly the most challenging thing I’ve ever done in my life, both physically and mentally.” Parazynski brought several objects with him to the world’s highest summit, including rocks from the Moon, and remembrances of fallen astronauts. Parazynski is the first astronaut to summit Mt. Everest.

During the climb, Parazynski was doing research. “We’ll be collecting data for astrobiologists, looking for extremophile life,” Parazynski told Universe Today in an interview before he left for Mt. Everest. “If you understand how extremophiles live, you might be able to understand how life may have once evolved on Mars, or may still exist on Mars.”

Scott Parazynski on the summit of Mt. Everest. Credit: OnOrbit.com

Parazynski tested NASA-derived hardware, taking along a prototype lunar geology camera and other hardware for extreme environments. “Up high on the mountain there are limestone formations, which are wonderful places to look for fossilized life,” he said,” and we’ll also look for melt water and primitive forms of life there; algae lichens, etc. If liquid water exists even for brief periods on Mars it may be in similar conditions to what we’ll find on Mt. Everest. We hope to bring samples back for scientists to look at.”

Now that he has successfully reached the summit, Parazynski said he won’t return to Everest. “Once is enough,” he said, adding that his family is glad he now has the bug to climb Everest out of his system.

Check out all the videos of Parazynski’s climb at Miles O’Brien’s blog at True/ Slant, as well as more images from Keith Cowing at On Orbit.com. Congratulations to Scott Parazynski!

And I just had to share this image of Parazynski on the summit after the sun rose. It looks just like Luke Skywalker on the planet Hoth at the beginning of “The Empire Strikes Back.”

Scott Parazynski at the summit. Credit: OnOrbit.com

Look for an upcoming special on the Discovery channel about Parazynski’s climb.

May 18, 2009December 24, 2015 by Nancy Atkinson

First Observations of Biological Particles in High-Altitude Clouds

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A team of atmospheric chemists has moved closer to what’s considered the “holy grail” of climate change science: the first-ever direct detections of biological particles within ice clouds. Ice in Clouds Experiment – Layer Clouds (ICE-L) team mounted a mass spectrometer onto a C-130 aircraft and made a series of high-speed flights through a type of cloud known as a wave cloud. Analysis of the ice crystals revealed that the particles that started their growth were made up almost entirely of either dust or biological material such as bacteria, fungal spores and plant material. While it has long been known that microorganisms become airborne and travel great distances, this study is the first to yield direct data on how they work to influence cloud formation.

The team, led by Kimberly Prather and Kerri Pratt of the University of California at San Diego, Scripps Institution of Oceanography, performed in-situ measurements of cloud ice crystal residues and found that half were mineral dust and about a third were made up of inorganic ions mixed with nitrogen, phosphorus and carbon–the signature elements of biological matter.

The second-by-second speed of the analysis allowed the researchers to make distinctions between water droplets and ice particles. Ice nuclei are rarer than droplet nuclei.

The team demonstrated that both dust and biological material indeed form the nuclei of these ice particles, something that previously could only be simulated in laboratory experiments.

“This has really been kind of a holy grail measurement for us,” said Prather.

“Understanding which particles form ice nuclei, and which have extremely low concentrations and are inherently difficult to measure, means you can begin to understand processes that result in precipitation. Any new piece of information you can get is critical.”

The findings suggest that the biological particles that get swept up in dust storms help to induce the formation of cloud ice, and that their region of origin makes a difference. Evidence is increasingly suggesting that dust transported from Asia could be influencing precipitation in North America, for example.

Researchers hope to use the ICE-L data to design future studies timed to events when such particles may play a bigger role in triggering rain or snowfall.

“If we understand the sources of the particles that nucleate clouds, and their relative abundance, we can determine their impact on climate,” said Pratt, lead author of the paper.

The effects of tiny airborne particles called aerosols on cloud formation have been some of the most difficult aspects of weather and climate for scientists to understand.

In climate change science, which derives many of its projections from computer simulations of climate phenomena, the interactions between aerosols and clouds represent what scientists consider the greatest uncertainty in modeling predictions for the future.

“By sampling clouds in real time from an aircraft, these investigators were able to get information about ice particles in clouds at an unprecedented level of detail,” said Anne-Marie Schmoltner of NSF’s Division of Atmospheric Sciences, which funded the research.

Source: EurekAlert

May 13, 2009December 24, 2015 by Nancy Atkinson

A New Drake Equation? Other Life Not Likely to be Intelligent

Radio Telescopes. Credit: University of Washington

Looking for signals from distant civilizations might be an effort in futility, according to scientists who met at Harvard University recently. The dominant view of astronomers at a symposium on the future of human life in the Universe seems to be that if other life is out there, it likely is dominated by microbes or other nonspeaking creatures.

Speakers reviewed how life on Earth arose and the many, sometimes improbable steps it took to create intelligence here. Radio astronomer Gerrit Verschuur said he believes that though there is very likely life out there — perhaps a lot of it — it is very unlikely to be both intelligent and able to communicate with us.

Verschuur presented his take on the Drake equation, formulated by astronomer Frank Drake in 1960, that provides a means for calculating the number of intelligent civilizations that it is possible for humans to make contact with.

The equation relates those chances to the rate of star and habitable planet formation. It includes the rate at which life arises on such planets and develops intelligence, technology, and interplanetary communication skills. Finally, it factors in the lifetime of such a civilization.

Using Drake’s equation, Verschuur calculated there may be just one other technological civilization capable of communicating with humans in the whole group of galaxies that include our Milky Way — a vanishingly small number that may explain why 30 years of scanning the skies for signs of intelligent life has come up empty.

“I’m not very optimistic,” Verschuur said.

Dimitar Sasselov, professor of astrophysics at Harvard and director of the Harvard Origins of Life Initiative, agreed with Verschuur that life is probably common in the universe. He said that he believes life is a natural “planetary phenomenon” that occurs easily on planets with the right conditions.

As for intelligent life, give it time, he said. Though it may be hard to think of it this way, at roughly 14 billion years old, the universe is quite young, he said. The heavy elements that make up planets like Earth were not available in the early universe; instead, they are formed by the stars. Enough of these materials were available to begin forming rocky planets like Earth just 7 billion or 8 billion years ago. When one considers that it took nearly 4 billion years for intelligent life to evolve on Earth, it would perhaps not be surprising if intelligence is still rare.

“It takes a long time to do this,” Sasselov said. “It may be that we are the first generation in this galaxy.”

Several speakers at the event hailed the March launch of NASA’s Kepler space telescope, which is dedicated to the search for Earth-like planets orbiting other stars. Several Harvard-Smithsonian Center for Astrophysics faculty members, including Sasselov, are investigators on the telescope mission.

Andrew Knoll describes the beginnings of life on Earth. Photograph by Stephanie Mitchell/Harvard News Office

Sasselov said he expects Kepler to quickly add to the 350 planets already found orbiting other stars. By the end of the summer, he said, it may have found more than a dozen “super Earths” or planets from Earth-size to just over twice Earth’s size that Sasselov expects would have the stability and conditions that would allow life to develop.

If life did develop elsewhere, Andrew Knoll, the Fisher Professor of Natural History, used the lessons of planet Earth to give an idea of what it might take to develop intelligence. Of the three major groupings of life: bacteria, archaea, and eukaryotes, only the eukaryotes developed complex life. And even among the myriad kinds of eukaryotes, complex life arose in just a few places: animals, plants, fungi, and red and brown algae. Knoll said he believes that the rise of mobility, oxygen levels, and predation, together with its need for sophisticated sensory systems, coordinated activity, and a brain, provided the first steps toward intelligence.

It has only been during the past century — a tiny fraction of Earth’s history — that humans have had the technological capacity to communicate off Earth, Knoll said. And, though Kepler may advance the search for Earth-like planets, it won’t tell us whether there’s life there, or whether there has been life there in the past.

Other speakers included J. Craig Venter, Freeman Dyson, Peter Ward, Andy Knoll, Maria Zuber, David Charbonneau, Juan Enriquez, and David Aguilar.

Source: PhysOrg

May 6, 2009December 24, 2015 by Ian O'Neill

Panspermia Flower Power

Panspermia is a hypothesis that suggests life isn’t an Earth-only affair. The seeds of life may have spread throughout the Solar System and beyond via chunks of rock or comets, encountering planetary bodies, transporting spores or bacteria to other worlds. In short, we could be living in a cosmic ecosystem linked through simple interplanetary vagabond bacteria.

However, panspermia remains in the realms of speculation as we haven’t found any examples of extraterrestrial life (so far), let alone the possibility that life may be roaming freely through the vacuum of space. But panspermia as a life-spreading mechanism remains a possibility.

Now, famous physicist and futurist Freeman Dyson has come forward with an idea about what we should be looking for during the search for extraterrestrial life. Dyson believes the search for ET is flawed, as we are looking for what we deem to be probable lifeforms; perhaps we should be looking for detectable lifeforms.

And what’s one of the most detectable forms of life we know of? Flowers. What’s more, these flowers may have spread as far afield as the Kuiper belt and the Oort cloud…

“I would say the strategy in looking for life in the universe [should be] to look for what’s detectable, not what’s probable,” Freeman Dyson said on Saturday at a conference in Cambridge, Massachusetts.

“We have a tendency among the theorists in this field to guess what’s probable. In fact our guesses are likely to be wrong,” Dyson said. “We never had as much imagination as nature.”

We only have nature on Earth to learn from; this is the only life we know. There’s a certain set of rules life on Earth lives by (i.e. life exists here because it has evolved to adapt to temperatures, pressures and availability of sustenance), there’s a possibility that extreme forms of life could exist on other planets, but until we find this life, we don’t know what rules that life lives by. So scientists will logically look for probable forms of life.

However, Dyson points out that we should look for the most detectable forms of life. And one such example is the flower.

The Arctic Poppy (pictured top) is a flower that forms a parabolic shape. This shape maximizes the light that reflects off the inside of the petals so the interior of the plant can utilize solar energy. In the Arctic, often light is at a premium, so the flower has adapted to make full use of the Sun it can receive. From a distance, these mini solar collectors reflect a lot of light, and they should create a good indicator that plant life is thriving.

Now if we think about the icy Jovian moon Europa, it is thought to contain a liquid water ocean beneath a thick crust of ice and astrobiologists are very keen to send a mission to probe this potential life-harbouring habitat. Unfortunately, it might be hard for any robotic submersible to drop into the depths of this sub-surface sea as the ice could be up to 100 km thick in places.

So Dyson suggests that perhaps we should send an orbiter to Europa, not to look for an indication of life in the sub-surface ocean, but to look for more detectable signs of life, like flowers on the surface of the icy planet. After all, many types of plants grow in extremely cold locations on Earth, perhaps extreme plants thrive on Europa’s surface too?

“You can imagine once you have flowers that get nourished from below, they could evolve in the direction of being independent,” said Dyson.

He points out that once these plants become established on a body such as Europa, there’s the possibility that the seeds of these plants become distributed around the Solar System. If we ignore the fact that “life as we know it” requires a certain amount of solar energy to survive (at an orbital distance that is neither too close or too far from the Sun; otherwise known as the “Goldilocks Zone”), plant life that can survive in astonishingly cold temperatures may have adapted to live as far afield as the Kuiper Belt (near the orbit of Pluto), or beyond.

These are fair points, but I’d be cautious about trying to imagine the unimaginable. Although we need to keep an open mind as to what extraterrestrial life might look like, and optimize our search for detectable signs of life, we need to remember that the only form of life we know of and can study is here on Earth, and it remains a good starting point when looking for life on other planets.

Still, the thought of Arctic Poppies growing on Europa is an interesting idea, as it is possible, if panspermia is proven, that the Europa Arctic Poppies could be a descendent of their terrestrial counterparts…

Original source: New Scientist

April 27, 2009December 24, 2015 by Nancy Atkinson

Submit Your Questions for Scott Parazynski and Keith Cowing

Scott and Danru on Pumor RI with Everest Behind Them. Credit: OnOrbit.com

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Former astronaut Scott Parazynski is making an attempt to climb Mt. Everest, and has been sharing his adventures via Twitter, and his blog on OnOrbit.com. As we reported in in our article about Parazynski in March, he wants to share his experiences with as many people as possible. Earlier today, his “media sherpa,” Keith Cowing from NASA Watch.com joined Parazynski at base camp and both Cowing and Parazynski have agreed to take questions from readers of Universe Today and answer them during their time on Mt. Everest. Parazynski has been blogging and Twittering during his preparations for the climb, and he even wants to Twitter from the summit. “I want to tell the story of exploration here on Earth and the corollaries it has with space exploration,” Parazynski told Universe Today before he left for Kathmandu, Nepal. “The intent is to share the story with as many people as we can, particularly young people.”

So submit your questions in the comments section and we’ll relay them on. Questions can be about mountain climbing or space exploration.

For more information about check out Scott’s Twitter feed, and the OnOrbit blog, and you can even track Parazynski with his SPOT GPS locator system — which is kind of interesting to look at, as you can see how he has been going up and down the mountain the past couple of weeks to acclimate his body to higher elevation.

April 17, 2009December 24, 2015 by Nancy Atkinson

Ancient Antarctic Ecosystem Could be Analog for Life on Other Worlds

An ecosystem found in this region of Antarctica. Courtesy of Jill Mikuck

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Scientists have found an ancient ecosystem below an Antarctic glacier, one that has survived millions of years without light or oxygen in a pool of brine. The ecosystem contains a diversity of bacteria that thrive in cold, salty water loaded with iron and sulfur. The water averages 14 degrees Fahrenheit, but doesn’t freeze because the water is three or four times saltier than the ocean. Scientists who discovered and studied the ecosystem found the bacteria convert the iron and sulfur into food. Life found in extreme conditions like this could explain how life might exist on other planets and serve as a model for how life can exist under ice. Some scientists have proposed that life could possibly be found under the outer ice layer of Jupiter’s moon Europa.

Described in the April 17 issue of Science, the ecosystem lives trapped below Taylor Glacier and next to frozen Lake Bonney in eastern Antarctica, said John Priscu a longtime Antarctic researcher. Despite their profound isolation, the microbes are remarkably similar to species found in modern marine environments, suggesting that the organisms now under the glacier are remnants of a larger population that once occupied an open fjord or sea.

Jill Mikucki, lead author of the article, added that life below the glacier may help scientists answer questions about life on “Snowball Earth,” the period when large ice sheets covered the Earth. “This briny pond is a unique sort of time capsule from a period in Earth’s history,” she said. “I don’t know of any other environment quite like this on Earth.”

Priscu said researchers discovered the bacteria while investigating Blood Falls, a curious blood-red feature that flows from Taylor Glacier. They learned that the falls are red because they draw water from an iron rich pool. They discovered different types of bacteria in their samples; the most common bacteria in called Thiomicrospira arctica.

The exact size of the subglacial pool is not known precisely, but it is thought to rest under 400 meters of ice some four kilometers from its tiny outlet at Blood Falls. The researchers can’t drill down to the pool because the glacier is too thick and the pool is too far back from the glacier’s nose, Priscu said.

Sources: EurekAlert, PhysOrg

April 9, 2009December 24, 2015 by Anne Minard

Without Nickel, Life on Earth Could Finally Breathe

Caption: Banded iron formations like this from northern Michigan contain evidence of a drop in dissolved nickel in ancient oceans. Credit: Carnegie Institution for Science

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Researchers have long puzzled over why oxygen flourished in Earth’s atmosphere starting around 2.4 billion years.

Called the “Great Oxidation Event,” the transition “irreversibly changed surface environments on Earth and ultimately made advanced life possible,” said Dominic Papineau of the Carnegie Institution’s Geophysical Laboratory.

Now, Papineau has co-authored a new study in the journal Nature, which reveals new clues to the mystery in ancient sedimentary rocks.

The research team, led by Kurt Konhauser of the University of Alberta in Edmonton, analyzed the trace element composition of sedimentary rocks known as banded-iron formations, or BIFs, from dozens of different localities around the world, ranging in age from 3,800 to 550 million years. Banded iron formations are unique, water-laid deposits often found in extremely old rock strata that formed before the atmosphere or oceans contained abundant oxygen. As their name implies, they are made of alternating bands of iron and silicate minerals.

They also contain minor amounts of nickel and other trace elements. And the history of nickel, the researchers think, may reveal a secret to the origin of modern life.

Nickel exists in today’s oceans in trace amounts, but was up to 400 times more abundant in the Earth’s primordial oceans. Methane-producing microorganisms, called methanogens, thrive in such environments, and the methane they released to the atmosphere might have prevented the buildup of oxygen gas, which would have reacted with the methane to produce carbon dioxide and water.

A drop in nickel concentration would have led to a “nickel famine” for the methanogens, who rely on nickel-based enzymes for key metabolic processes. Algae and other organisms that release oxygen during photosynthesis use different enzymes, and so would have been less affected by the nickel famine. As a result, atmospheric methane would have declined, and the conditions for the rise of oxygen would have been set in place.

The researchers found that nickel levels in the BIFs began dropping around 2.7 billion years ago and by 2.5 billion years ago was about half its earlier value.

“The timing fits very well. The drop in nickel could have set the stage for the Great Oxidation Event,” Papineau said. “And from what we know about living methanogens, lower levels of nickel would have severely cut back methane production.”

As for why nickel dropped in the first place, the researchers point to geology. During earlier phases of the Earth’s history, while its mantle was extremely hot, lavas from volcanic eruptions would have been relatively high in nickel. Erosion would have washed the nickel into the sea, keeping levels high. But as the mantle cooled, and the chemistry of lavas changed, volcanoes spewed out less nickel, and less would have found its way to the sea.

“The nickel connection was not something anyone had considered before,” Papineau said. “It’s just a trace element in seawater, but our study indicates that it may have had a huge impact on the Earth’s environment and on the history of life.”

Source: Carnegie Institution for Science, via Eurekalert.