Tag Archives: microbial

Ancient Mars could have been teeming with microbial life, researchers find | Mars

Ancient Mars may have had an environment capable of harboring an underground world teeming with microscopic organisms, French scientists reported on Monday. But if they existed, these simple life forms would have altered the atmosphere so profoundly that they triggered a Martian Ice Age and snuffed themselves out, the researchers concluded.

The findings provide a bleak view of the ways of the cosmos. Life – even simple life like microbes – “might actually commonly cause its own demise”, said the study’s lead author, Boris Sauterey, now a post-doctoral researcher at Sorbonne University.

The results “are a bit gloomy, but I think they are also very stimulating”, he said in an email. “They challenge us to rethink the way a biosphere and its planet interact.”

In a study in the journal Nature Astronomy, Sauterey and his team said they used climate and terrain models to evaluate the habitability of the Martian crust 4bn years ago when the red planet was thought to be flush with water and much more hospitable than today.

They surmised that hydrogen-gobbling, methane-producing microbes might have flourished just beneath the surface back then, with several inches (a few tens of centimeters) of dirt more than enough to protect them against harsh incoming radiation. Anywhere free of ice on Mars could have been swarming with these organisms, according to Sauterey, just as they did on early Earth.

Early Mars’s presumably moist, warm climate, however, would have been jeopardized by so much hydrogen being sucked out of the thin, carbon dioxide-rich atmosphere, Sauterey said. As temperatures plunged by nearly -400F (-200C), any organisms at or near the surface probably would have gone deeper in an attempt to survive.

By contrast, microbes on Earth may have helped maintain temperate conditions, given the nitrogen-dominated atmosphere, the researchers said.

The SETI Institute’s Kaveh Pahlevan said future models of Mars’s climate needed to consider the French research.

Pahlevan led a separate recent study suggesting Mars was born wet with warm oceans lasting millions of years. The atmosphere would have been dense and mostly hydrogen back then, serving as a heat-trapping greenhouse gas that eventually was transported to higher altitudes and lost to space, his team concluded.

The French study investigated the climate effects of possible microbes when Mars’s atmosphere was dominated by carbon dioxide and so is not applicable to the earlier times, Pahlevan said.

“What their study makes clear, however, is that if (this) life were present on Mars” during this earlier period, “they would have had a major influence on the prevailing climate,” he added in an email.

The best places to look for traces of this past life? The French researchers suggest the unexplored Hellas Planitia, or plain, and Jezero crater on the north-western edge of Isidis Planitia, where Nasa’s Perseverance rover is collecting rocks for return to Earth in a decade.

Next on Sauterey’s to-do list: looking into the possibility that microbial life could still exist deep within Mars.

“Could Mars still be inhabited today by microorganisms descending from this primitive biosphere?” he said. “If so, where?”

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NASA’s Mars Perseverance rover finds diversity, hints of microbial life in ancient lake bed rocks

NASA scientists said Thursday the Mars Perseverance rover found biologically-interesting rocks in an ancient lake bed that could indicate microbial life existed on the red planet billions of years ago.

After launching from Cape Canaveral, Florida, in July 2020, NASA successfully landed its second rover, Perseverance, on Mars in February 2021. Along for the ride was a 4-pound helicopter named Ingenuity that has been a wild success showing controlled flights can be made on Mars.

Since its touchdown, Percy has been roving around on the site of a dried-up ancient Martian river delta known as the Jezero Crater. The robot has seven science instruments, including cameras and two microphones that recorded the sounds of wind on Mars and its landing.

On Thursday, mission managers provided an update on what the rover had discovered while exploring 8 miles of the Jezero Crater. The area was likely a lake more than 3.5 billion years ago, which is why NASA landed the rover there, to search in an ancient habitable environment for evidence of life. 

“This mission is not looking for extant life things that are alive today,” Ken Farley, Perseverance project scientist, said. “Instead, we’re looking into the very distant past when Mars climate was very different than it is today, much more conducive to life.”

In more than 550 Sols, or Martian days, Farley said Perseverance has found that the history of the crater floor is more complicated than expected. Based on the findings of ingenious rock formed from volcanic activity, the science team now believes before holding a lake bed, the crater had some active volcanic activity, even a lava lake.

Rocks to be excited about: Wildcat Ridge and Skinner Ridge

Scientists said several rock samples collected on Mars contain organic molecules associated with life. Two rock samples, in particular, were collected from rocks the team has named Wildcat Ridge and Skinner Ridge, which have the science team excited. The stones were named after trails in the Shenandoah National Park.

The rocks, about 66 feet (20 meters) apart, offered very diverse samples, but each with a high science value, said Perseverance sample return scientist David Shuster. However, both samples have something in common.

“Both of these rocks are composed of sediments that were transported by liquid water,” Shuster said, adding both rocks experienced alterations involving water. “Thus, these rocks formed and record indications of a habitable environment.”

Using the rover’s instrument called Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals, or SHERLOC, to analyze the area where the rover collected the samples, the team found the highest concentration of organic matter yet during the mission. Organic matter, considered the building blocks of life, can be created through processes that involve life but also other circumstances, like geologic activity, not involving life.

“If this is a treasure hunt for potential signs of life on another planet, organic matter is a clue. And we’re getting stronger and stronger clues as we’re moving through our Delta campaign,” Perseverance SHERLOC instrument scientist Sunanda Sharma said. “I personally find these results so moving because it feels like we’re in the right place with the right tools at a very pivotal moment.”

The samples are about the size of a pinky and are stored in tubes until a follow-up mission can pick up the Martian rocks from Perseverance in 2030. 

What’s ahead? A critical robotic handoff 

The rover’s biggest job is still to come. 

Perseverance continues to take rock core samples and scout potential sample landing sites for a robotic sample-return mission.

To bring the first samples from Mars back to Earth, NASA and the European Space Agency have an elaborate plan involving a fleet of robots, including the Perseverance rover, a new Martian lander, a sample-catching spacecraft and two tiny helicopters.

The two space agencies simplified the original Mars sample return campaign mission, removing a sample fetch rover and its associated lander. NASA and ESA managers said they changed the plan because of the expected longevity of Perseverance, and the Ingenuity helicopter’s success, which has now completed 29 flights on Mars.

NASA Science Mission Directorate Associate Administrator Thomas Zurbuchen said the plan was always to have two methods of getting the samples back to Earth, using Perseverance or another rover for the handoff. 

Instead of an additional rover, the plan is to use two tiny helicopters as the backup option and Percy as the primary. The rover is the primary means to get the samples to the Sample Retrieval Lander, which will carry the Mars Ascent Vehicle and ESA’s robotic transfer arm.

Percy will also deposit a sample cache in the river delta as an “insurance policy” option before moving on to more ancient terrain on Mars. Future missions could pick up those samples.

The ultimate goal is to get the first Mars soil and rock samples back to Earth for a detailed analysis.

Sharma said bringing the rock cores back to Earth is the surest way to confirm the organic matter the science team believes it has found in the Mars rock samples. 

“Obviously, the instruments that we have in the rover are extraordinary, and the fact that we can make these observations of organic molecules on Mars, to begin with, it is just awesome,” Sharma said. “But it’s really the level of detail spatially that that will be different here on Earth.”

NASA’s head of planetary science, Lori Glaze said what the rover has found so far tells the team they picked the right spot on Mars to explore. 

“Just the complete body of work that’s been completed by this incredible Perseverance team to date tells me that we not only went to the right place, but we sent the right spacecraft with the right science instruments to explore this amazing ancient environment on Mars,” Glaze said.

Over the next few months, Perseverance will explore an area known as the Enchanted Lake to collect more samples.

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Ancient Microbial “Dark Matter” – Thousands of Unknown Bacterial Species Discovered in Hawaiian Lava Caves

Steve Smith in a Hawaiian cave passage filled with roots of the Kaʻu district on the Island of Hawai`i. Credit: Kenneth Ingham

Centuries-Old Lava Caves of Hawaiʻi Island Contain Thousands of Unknown Bacterial Species

Higher bacterial diversity than scientists expected has been uncovered in the lava caves, lava tubes, and geothermal vents on the big island of Hawaiʻi. The findings have been reported in a new study published today (July 21, 2022) in the journal Frontiers in Microbiology.

This research investigates the variety and interactions within these microbial ecosystems, which illustrate how life may have existed on

“This study points to the possibility that more ancient lineages of bacteria, like the phylum Chloroflexi, may have important ecological ‘jobs,’ or roles,” said first author Dr. Rebecca D Prescott of

Thick microbial mats hang under a rock ledge in steam vents that run along the Eastern Rift Zone on Hawaiʻi Island. Credit: Jimmy Saw

The harshest conditions—the geothermal sites—were expected to have lower diversity than the more established and habitable lava tubes. While the diversity was indeed found to be lower, the team of researchers was surprised to discover that the interactions within these communities were more complex than in locations with higher diversity.

“This leads to the question, do extreme environments help create more interactive microbial communities, with microorganisms more dependent on each other?” said Prescott. “And if so, what is it about extreme environments that helps to create this?”

Since Chloroflexi, and another class called Acidobacteria, were present at nearly all of the locations, they may play essential roles in these communities. However, these were not the most abundant bacteria, and the individual communities from the different sites showed large variations in the diversity and complexity of the microbial interactions. Counterintuitively, the most abundant groups, Oxyphotobacteria and Actinobacteria, were not often ‘hub’ species, suggesting that their roles may be less important to the overall structure of the community.

More questions than answers

Since the current study was based on the partial sequencing of one gene, it cannot accurately determine the species of microbes or their ‘jobs’ in the community. Therefore, further research is needed to help reveal the individual species that are present, as well as to better understand these bacteria’s roles in the environment.

A stalactite formation in a Hawaiian cave system from this study with copper minerals and white microbial colonies. Despite the fact that copper is toxic to many organisms, this formation hosts a microbial community. Credit: Kenneth Ingham

“Overall, this study helps to illustrate how important it is to study microbes in co-culture, rather than growing them alone (as isolates),” said Prescott. “In the natural world, microbes do not grow in isolation. Instead, they grow, live, and interact with many other microorganisms in a sea of chemical signals from those other microbes. This then can alter their gene expression, affecting what their jobs are in the community.”

Beyond the insights about past, or even future, life on Mars, bacteria from volcanic environments can also be useful in understanding how microbes turn volcanic rock (basalt) into soils, as well as bioremediation, biotechnology, and sustainable resource management.

Reference: “Islands Within Islands: Bacterial Phylogenetic Structure and Consortia in Hawaiian Lava Caves and Fumaroles” by Rebecca D. Prescott, Tatyana Zamkovaya, Stuart P. Donachie, Diana E. Northup, Joseph J. Medley, Natalia Monsalve, Jimmy H. Saw, Alan W. Decho, Patrick S. G. Chain and Penelope J. Boston, 21 July 2022, Frontiers in Microbiology.
DOI: 10.3389/fmicb.2022.934708

Funding: NASA Headquarters, George Washington University



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