Extremophiles: Why study them? What can they teach us about finding life beyond Earth?

Universe Today has conducted some incredible examinations regarding a plethora of scientific fields, including impact cratersplanetary surfacesexoplanetsastrobiologysolar physicscometsplanetary atmospheresplanetary geophysicscosmochemistry, meteorites, and radio astronomy, and how these disciplines can help scientists and the public gain greater insight into searching for life beyond Earth. Here, we will discuss the immersive field of extremophiles with Dr. Ivan Paulino-Lima, who is a Senior Research Investigator at Blue Marble Space Institute of Science and the Co-Founder and Chief Science Officer for Infinite Elements Inc., including why scientists study extremophiles, the benefits and challenges, finding life beyond Earth, and proposed routes for upcoming students. So, why is it so important to study extremophiles?

“The study of extremophiles represents the edge of the human knowledge in terms of the environmental limits where life forms can live, withstand, or preserve their integrity and living potential,” Dr. Paulino-Lima tells Universe Today. “For example, the exploration of the hot springs at Yellowstone led to the discovery of the Taq DNA polymerase from Thermus aquaticus, which was subsequently used to develop the polymerase chain reaction (PCR) technique. Just like the thermophiles, represented by organisms that thrive in hot temperatures, a growing diversity of microorganisms and ecosystems have been found in cold temperatures, extremes of pH, pressure, salinity, radiation, desiccation, and toxic substances.”

The study of extremophiles can be summed up as “life in extreme environments”, or environments that are inhospitable for most of life on Earth, including humans, plants, and animals. Extremophiles have been found to not only survive, but thrive, in the unlikeliest of environments on Earth, including hydrothermal vents, alkaline lakes, acid mine drainage, cosmic rays, sunlight, Mariana Trench, dry environments such as the McMurdo Dry Valley and Atacama Desert, gold mines, and even underneath ice shelves in Antarctica.

Along with the environments noted by Dr. Paulino-Lima, other types of extremophiles include those that can survive without oxygen, high amounts of carbon dioxide, dissolved heavy metals, and sulfur. Therefore, with their wide array of locations, what are some of the benefits and challenges of studying extremophiles?

“The study of extremophiles is often challenging because of their very nature that defies our traditional concepts,” Dr. Paulino-Lima tells Universe Today. “Some anaerobic microorganisms are extremely sensitive to oxygen and require anaerobic chambers and special techniques for their cultivation and routine maintenance. In terms of benefits, some types of extremophiles are very resistant to desiccation and can be preserved in a dry state for many years. Similarly, thermophiles can be preserved at room temperature for a long time since their normal metabolic activity happens at a much higher temperature.”

Finding life in such extreme environments on Earth has helped change the conversation regarding where scientists might find life beyond Earth, including Venus, Mars, Europa, Titan, Enceladus, and even exoplanets. Of these worlds, Europa and Enceladus have gained a lot of attention over the last few decades due to the existence of internal liquid water oceans within these small moons. It is currently hypothesized that hydrothermal vents could exist at the bottoms of these oceans, potentially providing nutrients for life, just like here on Earth. Currently, the NASA Europa Clipper mission is scheduled to be launched to Europa this October and arrive at Jupiter in 2030, with the goal of ascertaining the habitability potential for Europa and its internal ocean. Therefore, what can extremophiles teach us about finding life beyond Earth?

“The study of extremophiles allows us to establish empirical and theoretical limits to life on Earth, Dr. Paulino-Lima tells Universe Today. “With these limits, we can narrow down the search for life beyond Earth and constrain the habitats that Earth-like life could currently inhabit or could have inhabited at some point in the past. During our search for extraterrestrial life, it is very possible that we will come across even more exotic possibilities, known collectively as ‘alternative biochemistries’. For example, a different type of metabolism for carbon-based life has been proposed for Titan, one of Saturn’s moons. However, these possibilities remain theoretical or speculative, and have yet to be demonstrated in a laboratory. The search for life beyond Earth is necessarily guided by established knowledge, but with an open mind. Extremophiles represent the state of the art in terms of our established knowledge for the limits of Earth-like life.”

Aside from their astrobiological implications, extremophiles also present opportunities for use in a myriad of industries, including biotechnology, medical science, food processing, and clothing. For biotechnology, extremophiles that live in extreme heat, cold, salinity, and methane can be used for copying DNA, biofuel production, and biomining. For medical science, extremophiles that live in extreme dryness, radiation, acid, and vacuum can be used for DNA transfer, which is a crucial practice in repairing DNA damage resulting from a myriad of reasons. Therefore, with their myriad of astrobiological and industrial applications, what are some of the most exciting aspects about extremophiles that Dr. Paulino-Lima has studied during his career?

“One of the most exciting aspects of extremophiles that I have studied in my career is the fact that they can withstand the ultimate frontier of tolerance – outer space,” Dr. Paulino-Lima tells Universe Today. “This includes vacuum, extremes of temperature, blasts of radiation coming from the solar wind, cosmic rays, supernovas, all of that combined, and for an extended period. To me it is impossible to be aware of these facts and not to ask whether we are alone in the universe. The detection of a single spore anywhere in the solar system that excludes an Earth origin, or the detection of biosignatures from exoplanets, or even elaborate radio signals with sophisticated patterns coming from other solar systems, will take us to a new era of self-awareness and exploration, which will have a profound impact on the culture and future of our society.”

One of the most well-known extremophiles are tardigrades, also known as water bears, which are known for their extreme resilience in almost any environment, including outer space. These microscopic creatures can suspend their metabolism when under extreme environmental stressors, only to later reanimate without detrimental health effects. They have been observed to survive under any type of conditions, including starvation, freezing, boiling, extreme heat, and vacuum.

Image of a tardigrade, which is a microscopic species and one of the most well-known extremophiles, having been observed to survive some of the most extreme environments, including outer space. (Credit: Katexic Publications, unaltered, CC2.0)

Along with the myriad of extremophile types and the locations where they are found, studying extremophiles are equally accomplished by a myriad of scientific disciplines, including microbiologists and astrobiologists, who conduct field studies and collect samples to be examined and analyzed back in homebase laboratories. Through this, scientists learn the complex processes that enable extremophiles to survive in such harsh environments, all the way down to the organisms’ genetic material. Along with laboratory experiments and tests, scientists who study extremophiles collaborate with other disciplines, including organic geochemistry, biochemistry, geology, and stratigraphy, just to name a few. Therefore, what advice does Dr. Paulino-Lima have for upcoming students who wish to pursue studying extremophiles?

“Our society is based on all kinds of information,” Dr. Paulino-Lima tells Universe Today. “The trick is to select what can be turned into knowledge, what can lead to a path. Be wise to separate knowledge from mere information. Attend conferences, organize meetings, organize your time, and make connections. The best opportunities may be the ones you are not thinking of or have never imagined. My career would never be the same without all the answers and feedback that turned into the stepstones of my professional development. I would never have known if I had not asked. I will be forever grateful to everyone who played a role and helped shape my trajectory.”

As noted, the study of extremophiles comes from collaboration with other researchers and scientific disciplines. For example, Dr. Paulino-Lima and a member of his PhD committee, Dr. Lynn Rothschild (who was previously one of his primary publication references), have worked together on a myriad of projects at NASA Ames Research Center, including a satellite with biological experiments and a database designed to conduct a method to remotely identify extraterrestrial life. Additionally, he has worked with Dr. Jesica Urbina, who is currently the CEO at Infinite Elements Inc., on an innovative research project, as well.

The study of extremophiles is a multidisciplinary and collaborative effort, encompassing field work and laboratory experiments in hopes of further identifying where and how we can find life, both on Earth and beyond. It is through these efforts that scientists work to answer some of the most difficult questions throughout human history, including how did we get here and are we alone? As the study of extremophiles continues to grow and evolve with new methods and discoveries, the number of individuals involved in this incredible and unique field of study will undoubtedly grow and evolve along with it.

“Many people may feel discouraged to pursue a career in biological sciences because they feel unattracted by the tedious routine of laboratory experiments,” Dr. Paulino-Lima tells Universe Today. “I imagine this is especially true for the study of extremophiles. However, this is only one aspect of the scientific method. A large part comes from reading and staying up to date with the newest developments in a particular field. In a time where all biological information is digitized, the development of coding skills is fundamental for everyone who wants to study extremophiles from a bioinformatics perspective. For those who have an entrepreneur spirit, this is a vast area filled with exciting opportunities. Let your knowledge guide your imagination towards a better and more sustainable future.”

How will extremophiles help us better understand our place in the universe in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!