Three previously unknown strains of bacteria were found growing in the International Space Station, according to a recent genetic analysis. The discovery could help scientists develop better ways to grow food on Mars.
The analysis, published in the journal Frontiers in Microbiology, describes how astronauts collected four strains of bacteria within the space station in 2011, 2015 and 2016. It was part of an ongoing surveillance program that tasks astronauts with monitoring eight sites of the space station for bacterial growth.
Astronauts have already sent hundreds of samples back to Earth for analysis, and thousands more are scheduled to be sent back on return missions.
The newly discovered strains belong to a family of bacteria called Methylobacteriaceae, which is commonly found in soil and freshwater. These bacteria help plants grow, fix nitrogen and stop pathogens.
International Space Station
Credit: NASA
So, how did these novel microbes get in the space station? They likely came from the plant-growing experiments that astronauts have been conducting for years aboard the ISS, such as the Advanced Plant Habitat, an automated growth chamber that grows plants in space so scientists can study them back on Earth.
The new strains could be beneficial to space farming. After all, it's already clear that the bacteria can survive the conditions of the space station, and the researchers wrote that the strains might possess "biotechnologically useful genetic determinants" that could help astronauts grow food on long-term missions, or on other planets.
"To grow plants in extreme places where resources are minimal, isolation of novel microbes that help to promote plant growth under stressful conditions is essential," study authors Kasthuri Venkateswaran and Nitin K. Singh said in a press release.
"Needless to say, the ISS is a cleanly-maintained extreme environment. Crew safety is the number 1 priority and hence understanding human/plant pathogens are important, but beneficial microbes like this novel Methylobacterium ajmalii are also needed."
To accelerate their understanding of how bacteria behaves in space, Singh and Venkateswaran proposed developing customized equipment that astronauts could use to analyze bacteria on the space station.
"Instead of bringing samples back to Earth for analyses, we need an integrated microbial monitoring system that collect, process, and analyze samples in space using molecular technologies," they said. "This miniaturized 'omics in space' technology — a biosensor development — will help NASA and other space-faring nations achieve safe and sustainable space exploration for long periods of time."
Genome-based phylogenetic tree showing the phylogenetic relationship of Methylobacterium ajmalii sp. nov. with members of the family Methylobacteriaceae.
Credit: Bijlani et al.
NASA is hoping to send humans to Mars by the 2030s, while private companies like SpaceX are aiming to reach the Red Planet this decade. For any Mars mission, developing sustainable ways to grow food is critical. That's mainly because it's impractical for astronauts to pack the food they'll need for the journey, which will take 14 months roundtrip, not including time spent on the planet.
Astronauts also need to stay healthy. The main problem with prepackaged food, besides its weight, is that the nutrients break over time. That's why NASA has been experimenting with growing various types of nutritious plants through projects like Veggie and the more recent Advanced Plant Habitat. These projects help scientists learn about the complexities of growing plants in microgravity, and how plants might grow on Mars.
NASA astronaut and Expedition 64 Flight Engineer Kate Rubins checks out radish plants growing for the Plant Habitat-02 experiment.
Credit: NASA
But growing plants in space isn't all about nutrition. NASA notes that plants are psychologically beneficial to people, both on Earth and in space. These psychological benefits might become especially important to astronauts on long-term missions millions of miles away from Earth.
Here's how astronaut Peggy Whitson, who worked aboard the International Space Station, described seeing plants in space for the first time:
"It was surprising to me how great 6 soybean plants looked," she told Space Daily. "I guess seeing something green for the first time in a month and a half had a real effect. From a psychological perspective, I think it's interesting that the reaction was as dramatic as it was. [...] I guess if we go to Mars, we need a garden!"
"Do you think we are alone?" That question is, without fail, one of the first things people ask me when they learn I'm an astronomer. And I get why. It's also the question I most want an answer for. But that answer may depend a lot on what kind of life the universe favors (if it favors any at all). So, the question I want to briefly touch on today is how common will it be for any life that appears on any planet in the universe to start climbing up the evolutionary ladder of complexity?
On Earth, the history of life is mainly a story of single cells. Earth's origin lies some 4.5 billion years ago, and the best fossil records put the emergence of life as single-celled creatures about a billion years later. After life's first appearance, almost two billion years go by during which all evolutionary activity was on those single-celled organisms. There was some really amazing biochemical machinery evolving within those little cells but if you are interested in multicellular creatures, they don't appear until sometime around 700 million years ago.... if there is one thing we know is true, it's that nature is more clever than we are. That means it may know lots of ways to produce animals without oxygen around or even in the presence of buckets of CO2.
What are we to make of this incredibly long run of Earth as Planet Bacteria? (Note, there were actually other kinds of single-celled creatures too). Well, it certainly tells us that evolutionary success does not demand multicellularity. During these long eons, life invented the most amazing array of nano-machines for a jaw-dropping variety of purposes. For example, single-celled critters invented photosynthesis for turning sunlight into sugars, metabolisms for turning sugars into energy, and complex intracellular transport mechanisms to move stuff where it was needed and get rid of waste. Earth before plants and animals was already a fertile place full of life that had, in its way, become spectacularly complex at least on the level of biochemistry.
Given the long run of this version of Earth, it may be that there is no reason that more complex life should be expected to form in all or even most cases on other planets.
Protozoa—a term for a group of single-celled eukaryotes—and green algae in wastewater, viewed under the microscope.
Credit: sinhyu via Adobe Stock
Another way the story of life on Earth might not get repeated elsewhere in the cosmos relates to the composition of planetary atmospheres. Our world did not begin with its oxygen-rich air. Instead, oxygen didn't show up until almost two billion years after the planet formed and one billion years after life appeared. Earth's original atmosphere was, most likely, a mix of nitrogen and CO2. Remarkably it was life that pumped the oxygen into the air as a byproduct of a novel form of photosynthesis invented by a novel kind of single-celled organism, the nucleus-bearing eukaryotes. The appearance of oxygen in Earth's air was not just a curiosity for evolution. Life soon figured out how to use the newly abundant element and, it turns out, oxygen-based biochemistry was supercharged compared to what came before. With more energy available, evolution could build ever larger and more complex critters.
Oxygen may also be unique in allowing the kinds of metabolisms in multicellular life (especially ours) needed for making fast and fast-thinking animals. Astrobiologist David Catling has argued that only oxygen has the right kind of chemistry that would allow for animals to form on any world.
Atmospheres may play another role in what can and can't happen in the evolution of life. In 1959, Su-Shu Huang proposed that each star would be surrounded by a "habitable zone" of orbits where a planet would have temperatures neither too hot nor too cold to keep life from forming (i.e. liquid water could exist on the planet's surface). Since then, the habitable zone has become a staple of astrobiological studies. Astronomers now know that the outer part of the habitable zone will be dominated by worlds with lots of greenhouse gases like CO2. A planet in a location like Mars, for example, would require a thick CO2 blanket to keep its surface above freezing. But all that CO2 could present its own problems for life. Almost all forms of animal life on Earth, including sea creatures, die when placed in CO2-rich environments. This has led astronomer Eddie Schwieterman and colleagues to propose a habitable zone for complex life: A band of orbits where planets can stay warm without requiring heavy CO2 atmospheres. According to Schwieterman, animal life of the kind we know would only be able to form in this much thinner band of orbits.
So, we have three lines of evidence that may suggest multicellular life (including thinking animals) may not be the road most taken across the universe. If this were true, then the galaxy might be awash with life but be sparse in terms of tentacles, paws, or boots on the ground.
Now, before your shoulders sag in sadness, it's important to note some facts. First, there are likely 400 billion planets in our galaxy alone. This provides a lot of leeway for experimentation. Second, if there is one thing we know is true, it's that nature is more clever than we are. That means it may know lots of ways to produce animals without oxygen around or even in the presence of buckets of CO2.
We just won't know until we start looking. And here is the good news. We finally are ready to start looking.
It's likely you've seen some of the fascinating videos of starling murmurations, great swarms of birds mysteriously flying as if with a single mind. These gigantic shapes swoop and swirl, shapeshifting their way through the skies while maintaining miraculous integrity. Maybe you've seen schools of fish shifting together into new shapes in likewise dazzling displays of synchrony.
How do these things happen? Consider them super-sized examples of a newly described state of matter that scientists at the University of Leicester in the U.K. are calling "swirlons." And swirlons are something new: They stand in some ways outside Newtonian law.
Swirlons are described in a paper recently published in Scientific Reports.
Lawbreakers
Credit: Wikimedia Commons/Big Think
According to Newton's Second Law, the acceleration of an object depends on both the force acting upon it and the object's mass. Its acceleration increases in accordance with the force being exerted, and as its mass increases, the object's acceleration decreases. These things don't happen with swirlons.
It appears that the Second Law relates only to passive, non-living objects at small and large scales. Swirlons, however, are comprised of active, living matter that moves courtesy of its own internal force. In this context, individual starlings are analogous to self-propelled particles within the larger swirlonic object, their flock.
Spotting swirlonic motion
Credit: Johnny Chen/Unsplash
The scientists at Leicester, led by mathematician Nikolai Brilliantov, came upon swirlonic matter as they developed computer models of self-propelled particles similar to simple bacteria or nanoparticles. They were interested in better understanding the movement of human crowds evacuating a crowded space, and these particles served as human stand-ins.
The word "swirlonic" comes from the circular direction in which the scientists witnessed their particles milling about in clusters that operated together as larger quasi-particles.
"We were completely baffled," says Brilliantov, "to witness how these quasi-particles swirl within active matter, behaving like individual super-particles with surprising properties including not moving with acceleration when force is applied, and coalescing upon collision to form swirlons of a larger mass."
Brilliantov tells Live Science, "[They] just move with a constant velocity, which is absolutely surprising."
It's not the first time such behavior has been seen, but the first time it's been identified as a distinct state of matter. Says Brilliantov, "These patterns have previously been observed for animals at different evolution stages, ranging from plant-animal worms and insects to fish, but rather as singular structures, not as a phase which borders other phases, resembling gaseous and liquid phases of 'normal' matter."
The researchers also saw that swirlonic particles operate on a sort of "one for all, all for one" basis. With passive particles such as water, different individual particles can exist in different states: some may evaporate into gas as others remain as liquid. The models of active particles, on the other hand, stuck together in the same state as either a liquid, solid, or gas.
Moving forward, and back, or up, or down together
Brilliantov and his colleagues hope to explore swirlons further, moving beyond their simulation into real-world investigations and experiments.
The researchers are also developing more sophisticated models that mimic the behavior of swirlonic animals such as starlings, fish, and insects. In these models, the active particles will have information-processing capabilities that allow them to make movement decisions as living creatures presumably do. They hope these models will reveal some of the secrets behind flocking, schooling, and swarming.
Another future possibility is creating man-made active particles that can self-assemble. Other Leicester experts agree that this is reason alone to continue researching swirlons.
In any event, says study co-author Ivan Tyukin, "It is always exciting to consider deepening our understanding of novel phenomena and their guiding physical principles. What we know to date is so much less than what there is to know. The phenomenon of the 'swirlon' is part of the tip of the iceberg of hidden knowledge. It leaves us with the eternal question: 'what else don't we know'?"
