5 microscopic organisms that could help us travel space!
Image credit: Pixabay
Earlier this year, I read a story about ISS astronauts finding algae on the outside of the space station. I found this fascinating, and my imagination ran wild with the possibilities of even single celled plant life being able to live outside of our atmosphere in space. In fact, that was the idea that sparked this blog topic. I had wanted to feature the algae in its own section here, but when I went to look into it further, I could find very little about it from authentic sources, and nothing about whether the algae had been alive and thriving on the outside of the space station, as the samples they took were obviously dead by the time they were examined more closely, and studying them where they were found was not a possibility for the astronauts of the space station, as there is only limited time for space walks. What I ended up looking into after finding that dead end turned out to be the fascinating study of extrempohiles to further our abilities to explore space.
Image credit: Pixabay
An enhanced image of E. coli
An extremophile is a living microbial organism that can survive in harsh environments in which most other life forms could not--such as in methane gas, in extreme cold, in a lack of atmosphere, or in acidic gasses or liquid. There are many different types of extremophiles, each specially suited to the environments they can thrive in. The study of these very organisms is currently being used in the creation of synthetic biology that will be useful to mankind in space travel and exploring (and hopefully settling) other planets. One of the leading institutes in these studies is The Carl Sagan Institute, which was founded in May 2015 at Cornell University, and was established specifically to focus on multidisciplinary research to explore planets and planetary systems, including whether or not other planets can harbor life--which, right now, has a lot to do with the study of these little microbial extremophiles. Let's zoom in for a closer look at some of them.
5. Escherichia Coli
E. Coli is a common bacteria that can be found living in the lower intestines of humans as well as many animals. Most strains are harmless, but some strains are what cause violent food poisoning in humans, if they are consumed on food; E. coli has also been known to cause some infections. So, what's such a common bacteria got to do with space? Well, what makes E. coli an extremophile is the fact that it is anaerobic and does not require oxygen. It is common and inexpensive to cultivate for testing.
Here is a link to the published results of the first experiment exposing E. coli to the radiation in space. The study was on the breeding of microorganisms under space conditions. The results were that some strains mutated slightly and became more resistant to antibiotics. It is still unclear if this was the result of reduced gravity on the liquid in the colonies combined with the liquid delivery of antibiotics.
4. Tardigrades
Image of a tardigrade taken by a scanning electron microscope.
Tardigrades are tiny, microscopic animals that can survive extreme conditions. They are not actually classified as extremophiles, but they are here on honorable mention because 1. they fascinate me, 2. they have been a crucial part in experimenting with organisms that can survive the atmospherelessness of space; and 3. I think they're really adorable for microscopic organisms. While nearly microscopic (largest species can be up to just over a millimeter when full grown) they are definitely not single-cell organisms. They are entire tiny animals with little brain organs, little digestive systems, and cute little feet with cute little claws. Tardigrades are also called "water bears," which was their original name given upon discovery by German pastor Johann Goeze in 1773. The name was given because the way they move with their stubby little feet is similar to the way a bear bumbles around.
Tardigrades have been the unsuspecting participants in several interesting studies and tests of their ability to endure extremes. It has been found that they can survive limited amounts of time in extreme heat, they can survive being frozen up to -200 degrees Celsius for several days, and have even been known to survive being frozen up to one degree above absolute zero for a few minutes. They can survive being dehydrated down to 3% water (from a natural, normal 85%) for up to 10 years. Most fascinating out of these studies is their ability to survive radiation and the vacuum of outer space with no protection. Tardigrades can survive up to 1,000 times the lethal radiation dose for humans and any other animal. And they have been exposed to outer space with survival rates of about 68% of subjects. In 2007, in an experiment called Tardigrades in Space, or TARDIS (not-so-subtle shoutout to Whovians!), three thousand tardigrades were launched into space on ESA's Foton M-3 mission, with a very successful survival rate.
3. Haloarchaea
These single celled organisms, Haloarchaea, were formerly classified as Halobacteria. The main distinguishable difference between archaea and bacteria is that the cells that are archaea have no nuclei. These little guys here, the Haloarchaea, have about 190 different species, and what makes them unique as an extremophile is that they exist in highly salinated environments, like the salt saturated waters of the Dead Sea. They cannot survive in fresh water, and need the salt in their environment to survive.
Haloarchaea subspecies have been featured in several experiments to test their durability against conditions found in space as well as on the surface of Mars. This article published with the National Center for Biotechnology Information highlights the results of some trials and tests conducted on the heartiness of Haloarchaea. In a couple of experiments from the mid '90s, simulations of Mars's soil and radiation conditions were made (on Earth), and Haloarchaea did not actually pass the exposure tests. It is speculated that they died because they were exposed to far more than they would have had to endure on the actual surface of Mars, though. They were also exposed to actual space radiation in the BIOPAN mission of 1994, where they were dried onto and into different mediums such as clay and soil, and launched into orbit to experience radiation from the Sun. More recently, Haloarchaea have been a part of the EXPOSE-E, EXPOSE-R and EXPOSE-R2 missions with ESA, where the archea were sent to the ISS for long-term radiation exposure tests. The results of these have not yet been published.
2. Chroococcidiopsis
Chroococcidiopsis is a primitive cyanobacteria, or blue green algae. An interesting fact about this algae is that its preferred environment for colonization is on the underside of translucent rocks. The rocks let through just enough sunlight for it to survive through photosynthesis, while protecting it from arid environments.
NASA's astrobiology division has speculated that hardy Chroococcidiopsis could be successfully introduced to the harsh terrain of Mars. This could theoretically begin cultivating an atmosphere and gentler conditions for introducing more plant life, and eventually other life.
1. Deinococcus Radiodurans
Wow, just look at that name! Not only does Deinococcus radiodurans have the coolest name, it has the most durability out of all of the extremophiles that science has discovered. It is also known in some circles of the scientific community as "Conan the Bacterium," because of its many "strengths" against harsh conditions. As its Latin name implies, D. radiodurans is resistant to radiation. Its prefixes and suffixes roughly translate to "terrible berry that withstands radiation." It can also happily survive dehydration, extreme cold, the vacuum of space, as well as highly acidic environments. This multifaceted durability is what qualifies it as a polyextremophile.
D. radiodurans was accidentally discovered in 1956, by Arthur W. Anderson, who was conducting an experiment to see if canned food could be sterilized using doses of gamma radiation--I know, the 50's, right? So, the bacteria itself was discovered at the same time as its then apparent resistance to radiation. Since the 1990s, extensive research has been done on D. radiodurans. NASA has experimented with its resistance to radiation, examined its DNA, and considered modifying it to human benefit to be used in medicine (in space!). It has also been named the world's toughest bacteria by the Guinness Book of World Records.
I saved this for last, since the video is quite in depth. Here, you will find an amazing video of Dr. Lynn Rothschild of NASA Ames talking about microbiology, her studies of extremophiles, and their massive potential to help us survive in space and on other planets. This footage was taken at the opening ceremony for the Carl Sagan Institute. In the video, Dr. Rothschild talks in depth about astrobiology studies and how they can be beneficial to space travel and survival.