According to the most widely accepted theories, evolutionary biologists assert that life on Earth began roughly 4 billion years ago, beginning with single-celled bacteria and gradually giving way to more complex organisms. According to this same evolutionary timetable, the first complex organisms emerged during the Neoproterozoic era (ca. 800 million years ago), which took the form of fungi, algae, cyanobacteria, and sponges.
However, due to recent findings made in the Arctic Circle, it appears that sponges may have existed in Earth’s oceans hundreds of millions of years earlier than we thought! These findings were made by Prof. Elizabeth Turner of Laurentian University, who unearthed what could be the fossilized remains of sponges that are 890 million years old. If confirmed, these samples would predate the oldest fossilized sponges by around 350 million years.
Some lucky astronomers get to work with some of the rarest material in the world. Real Martian meteorites are extraordinarily rare, but are invaluable in terms of understanding Martian geology. Now, one of the most famous meteorites, nicknamed “Black Beauty”, is helping shed light on a much more speculative area of science: Martian biology.
At the bottom of the ocean in the South Pacific Gyre, there’s a sediment layer that is among the most nutrient-starved environments on Earth. Because of conditions in that area, there’s almost no “marine snow”—the shower of organic debris common in the ocean—that falls to the ocean floor. Without all that organic debris falling to the floor, there’s a severe lack of nutrients there, and that makes this one of the least hospitable places on Earth.
A team of researchers took sediment samples from that area, and extracted 101.5 million year old microbes. When they “fed” those microbes, they sprang back to life.
The results are expanding our knowledge of microbial life and how long it can be dormant when conditions force it to be.
It’s time to update the rules. That’s the conclusion of a panel that examined NASA’s rules for planetary protection. It was smart, at the dawn of the space age, to think about how we might inadvertently pollute other worlds with Earthly microbes as we explore the Solar System. But now that we know a lot more than we did back then, the rules don’t fit.
As we send rovers and landers to other worlds, we have to think about the tiny microbial astronauts we’re sending along with us. In fact, NASA is so concerned about infecting other worlds that it has established the planetary protection protocols. Just to be safe.
Seeking to understand more about space-born microbes, NASA has initiated a program known as Genes in Space-3 – a collaborative effort that will prepare, sequence and identify unknown organisms, entirely from space. For those who might be thinking that this sounds a lot like the film Life – where astronauts revive an alien organism on the International Space Station and everyone dies! – rest assured, this is not the setup for some horror movie.
In truth, it represents a game-changing development that builds on recent accomplishments, where DNA was first synthesized by NASA astronaut Kate Rubin aboard the International Space Station in 2016. Looking ahead, the Genes in Space-3 program will allow astronauts aboard the ISS to collect samples of microbes and study them in-house, rather than having to send them back to Earth for analysis.
The previous experiments performed by Rubin – which were part of the Biomolecule Sequencer investigation – sought to demonstrate that DNA sequencing is feasible in an orbiting spacecraft. The Genes in Space-3 seeks to build on that by establishing a DNA sample-preparation process that would allow ISS crews to identify microbes, monitor crew health, and assist in the search for DNA-based life elsewhere in the Solar System.
As Sarah Wallace – a NASA microbiologist and the project’s Principal Investigator (PI) at the Johnson Space Center – said in a recent press release:
“We have had contamination in parts of the station where fungi was seen growing or biomaterial has been pulled out of a clogged waterline, but we have no idea what it is until the sample gets back down to the lab. On the ISS, we can regularly resupply disinfectants, but as we move beyond low-Earth orbit where the ability for resupply is less frequent, knowing what to disinfect or not becomes very important.”
Developed in partnership by NASA’s Johnson Space Center and Boeing (and sponsored by the ISS National Lab), this project brings together two previously spaceflight-tested molecular biology tools. First, there is miniPCR, a device which copies targeted pieces of DNA in a process known as Polymerase Chain Reaction (PCR) to create thousands of copies.
This device was developed as part of the student-designed Genes in Space competition, and was successfully tested aboard the ISS during the Genes in Space-1 experiment. Running from September to March of 2016, this experiment sought to test if the alterations to DNA and the weakening of the immune system (both of which happen during spaceflight) are in fact linked.
This test will be followed-up this summer with Genes in Space-2 experiment. Running from April to September, this experiment will measure how spaceflight affects telomeres – the protective caps on our chromosomes that are associated with cardiovascular disease and cancers.
The MinION, meanwhile, is a handheld device developed by Oxford Nanopore Technologies. Capable of analyzing DNA and RNA sequences, this technology allows for rapid analysis that is also portable and scalable. It has already been used here on Earth, and was successfully tested aboard the ISS as part of the Biomolecule Sequencer investigation earlier this year.
Combined with some additional enzymes to demonstrate DNA amplification, the Genes in Space-3 experiment will allow astronauts to bring the lab to the microorganisms, rather than the reverse. This will consist of crew members collecting samples from within the space station and then culturing them aboard the orbiting laboratory. The samples will then be prepared for sequencing using the miniPCR and sequenced and identified using the MinION.
As Sarah Stahl, a microbiologist and project scientist, explained, this will allow crews to combat the spread of infectious diseases and bacteria. “The ISS is very clean,” she said. “We find a lot of human-associated microorganisms – a lot of common bacteria such as Staphylococcus and Bacillus and different types of familiar fungi like Aspergillus and Penicillium.”
In addition to being able to diagnose illnesses and infections in real-time, the experiment will allow for new and exciting research aboard the ISS. This could include identifying DNA-based life on other planets, the samples of which would be returned to the ISS via probe. In addition, if and hen microbes are found floating around in space, they could be returned to the ISS for swift analysis.
Another benefit of the program will come from Earth-based scientists being able to access the experiments going on aboard the ISS in real-time. And scientists here on Earth will also benefit from the tools being employed, which will allow for cheap and effective ways to diagnose viruses, especially in parts of the world where access to a laboratory is not possible.
Once more, the development of systems and tools for use in space – an environment that is not typically conducive to Earth-based technologies – is offering up applications that go far beyond space travel. And in the coming years, ISS-based genetic research could help in the ongoing search for extra-terrestrial life, as well as provide new insights into theories like panspermia (i.e. the cosmos being seeded with life by comets, asteroids and planetoids).
Be sure to enjoy this video titled “Cosmic Carpool”, courtesy of NASA’s Johnson Space Center:
Europa is probably the best place in the Solar System to go searching for life. But before they’re launched, any spacecraft we send will need to be squeaky clean so don’t contaminate the place with our filthy Earth bacteria. Continue reading “Will We Contaminate Europa?”
Here’s a finding to give planetary protectionists pause: two species of spores mounted on the International Space Station’s hull a few years back showed a high survival rate after 18 months in space.
Providing that they are shielded against solar radiation, it appears the spores are quite hardy and could easily transport on a spacecraft headed for Mars — which is concerning since so many scientific investigations there these days are focused on habitability of Martian life (whether past or present). The experiment was published in 2012, but highlighted in a recent NASA press release about planetary protection.
The experiment was called PROTECT (an acronym of Resistance of spacecraft isolates to outer space for planetary protection purposes) and studied spores of Bacillus subtilis 168 and Bacillus pumilus SAFR-032. B. pumilus spores were found in an air lock between a “clean room” and entrance floor at NASA’s Jet Propulsion Laboratory, and in previous studies were shown to be more resistant to UV radiation and hydrogen peroxide than “wild” strains. B. subtilis is a spore that has been studied in other space environment experiments.
Samples of both spores were mounted on the EXPOSE-E facility on the space station, which provides up to two years of space exposure. The major goal of this European Space Agency experiment is to study “the origin, evolution and distribution of life in the universe,” NASA states, adding that anything mounted outside of there has to survive “cosmic radiation, vacuum, full-spectrum solar light including UV-C, freezing/thawing cycles [and] microgravity.”
The experiment found that if the spores were in areas replete with solar UV radiation, most of them were killed. If those rays were filtered out, however, the spores showed a 50 percent survival rate on both space and simulated “Mars” conditions. It is most concerning to scientists when considering a situation where spores could be hiding underneath each other during a spacecraft trip. The ones on the outside would likely die, but the ones on the inside — shielded from solar radiation — could make it there.
One key limitation in this study, however, is that only two types of spores were studied. This does present a case for doing more studies on this matter in the future, however. Space agencies are quite aware of the problem of planetary protection, as evidenced by departments such as NASA’s Office of Planetary Protection and ESA’s Planetary Protection Officer.
Spacecraft designers constantly make decisions to keep the extraterrestrial bodies we study as safe from Earth contamination as possible; one famous example was when the Galileo probe was deliberately sent into Jupiter in 2003 to protect Europa and other potentially life-bearing moons of the giant planet from possible contamination.
The rock study (led by Tuscia University’s Silvano Onofri) takes the question of the spores in a different direction, which is examining the phenomenon of “lithopanspermia” — how organisms might move between planets (say, on a meteor). Since Mars meteorites have been found on Earth, some researchers have wondered if life could have spread between our two planets. If that were to happen, the researchers cautioned, the spores would have to survive for thousands or millions of years.
The other B. pumilus paper (led by NASA’s Parag A. Vaishampayan) noted that those spores mounted outside of the space station that survived, showed higher concentrations of proteins that could be linked to resisting UV radiation.
Lake Vida lies within one of Antarctica’s cold, arid McMurdo Dry Valleys (Photo: Desert Research Institute)
Even inside an almost completely frozen lake within Antarctica’s inland dry valleys, in dark, salt-laden and sub-freezing water full of nitrous oxide, life thrives… offering a clue at what might one day be found in similar environments elsewhere in the Solar System.
Researchers from NASA, the Desert Research Institute in Nevada, the University of Illinois at Chicago and nine other institutions have discovered colonies of bacteria living in one of the most isolated places on Earth: Antarctica’s Lake Vida, located in Victoria Valley — one of the southern continent’s incredibly arid McMurdo Dry Valleys.
These organisms seem to be thriving despite the harsh conditions. Covered by 20 meters (65 feet) of ice, the water in Lake Vida is six times saltier than seawater and contains the highest levels of nitrous oxide ever found in a natural body of water. Sunlight doesn’t penetrate very far below the frozen surface, and due to the hypersaline conditions and pressure of the ice water temperatures can plunge to a frigid -13.5 ºC (8 ºF).
Yet even within such a seemingly inhospitable environment Lake Vida is host to a “surprisingly diverse and abundant assemblage of bacteria” existing within water channels branching through the ice, separated from the sun’s energy and isolated from exterior influences for an estimated 3,000 years.
Originally thought to be frozen solid, ground penetrating radar surveys in 1995 revealed a very salty liquid layer (a brine) underlying the lake’s year-round 20-meter-thick ice cover.
“This study provides a window into one of the most unique ecosystems on Earth,” said Dr. Alison Murray, one of the lead authors of the team’s paper, a molecular microbial ecologist and polar researcher and a member of 14 expeditions to the Southern Ocean and Antarctic continent. “Our knowledge of geochemical and microbial processes in lightless icy environments, especially at subzero temperatures, has been mostly unknown up until now. This work expands our understanding of the types of life that can survive in these isolated, cryoecosystems and how different strategies may be used to exist in such challenging environments.”
Sterile environments had to be set up within tents on Lake Vida’s surface so the researchers could be sure that the core samples they were drilling were pristine, and weren’t being contaminated with any introduced organisms.
According to a NASA press release, “geochemical analyses suggest chemical reactions between the brine and the underlying iron-rich sediments generate nitrous oxide and molecular hydrogen. The latter, in part, may provide the energy needed to support the brine’s diverse microbial life.”
“This system is probably the best analog we have for possible ecosystems in the subsurface waters of Saturn’s moon Enceladus and Jupiter’s moon Europa.”
– Chris McKay, co-author, NASA’s Ames Research Center
What’s particularly exciting is the similarity between conditions found in ice-covered Antarctic lakes and those that could be found on other worlds in our Solar System. If life could survive in Lake Vida, as harsh and isolated as it is, could it also be found beneath the icy surface of Europa, or within the (hypothesized) subsurface oceans of Enceladus? And what about the ice caps of Mars? Might there be similar channels of super-salty liquid water running through Mars’ ice, with microbes eking out an existence on iron sediments?
“It’s plausible that a life-supporting energy source exists solely from the chemical reaction between anoxic salt water and the rock,” explained Dr. Christian Fritsen, a systems microbial ecologist and Research Professor in DRI’s Division of Earth and Ecosystem Sciences and co-author of the study.
“If that’s the case,” Murray added, “this gives us an entirely new framework for thinking of how life can be supported in cryoecosystems on earth and in other icy worlds of the universe.”
More research is planned to study the chemical interactions between the sediment and the brine as well as the genetic makeup of the microbial communities themselves.
The research was published this week in the Proceedings of the National Academy of Science (PNAS). Read more on the DRI press release here, and watch a video below showing highlights from the field research.
Funding for the research was supported jointly by NSF and NASA. Images courtesy the Desert Research Institute. Dry valley image credit: NASA/Landsat. Europa image: NASA/Ted Stryk.)