Science of the Springs Astrobiology in Yellowstone National Park Grand prismatic spring in Yellowstone National Park. The different colors are due to different microorganisms that live there. All images that are un-cited are from nasaimages.org or from MSU’s research coordination network : rcn.montana.edu and are free for us to use

What is Astrobiology? Astro: + Biology: 3 main questions stars, universe + Biology: the study of life New field of science: combines geology, biology, chemistry, astronomy 3 main questions How did life begin? Are we alone? What is the future of life on Earth and beyond? Astrobiology is the study of life in the universe, including our own. This field combines several fields of science including geology, biology, chemistry, astronomy, physics, even philosophy. Astrobiologists search for aliens by understanding more about the life on our own planet combined with knowledge of the solar system and universe. Astrobiologist try to answer these three main questions. They want to know if life can form spontaneously on other planets or how it may have on our own. By researching ways for life to have originated on Earth, astrobiologists learn what a planet needs for life to form. Later we will learn how Yellowstone national park is useful to astrobiologists that study the origin of life on early Earth. Astrobiologists want to find out the likelihood of life existing other places in the universe. Some scientists listen to the universe to try and communicate with alien civilizations. Most astrobiologists believe that there is life out there, but that it is probably microscopic, like bacteria, not the little green men you see in movies. By studying the effects of current environmental changes happening on Earth, astrobiologists can learn more about the possible future of life on Earth. The more scientists learn about the way organisms respond to change, the better they can predict the future of life as the Earth changes. Earth can be used as a model for other planets they may have life. NASA teams up with researchers around the country and globe to try to get closer to answering these questions. Montana State University researchers use Yellowstone National Park to try to address all three of these questions.

Yellowstone Hot Springs and Extraterrestrial Life: What’s the connection? Environments as analogs Early Earth Extrasolar planets Limits of life Habitability Extremophiles Because astrobiologists can’t study life on early Earth or extrasolar planets directly, they must find a current environment similar to the real environment they want to study. The comparable environment is called an analog. An analog has most of the same properties as the real person, place, or thing that you are trying to study, and is used or studied in place of the real thing. Scientists at Montana State University study the environment of Yellowstone as an analog to early Earth because the conditions are similar. Early Earth was hot, wet, and had a lot of geothermal (or volcanic) activity. This description fits Yellowstone as well, making Yellowstone a good analog to early Earth. You can imagine an extrasolar planet that fits this description as well. By studying the living things in the Yellowstone geothermal features, called extremophiles, scientists can learn more about possible living things on early Earth or on extrasolar planets because the environments are analogous. Yellowstone also helps scientists learn about the limits of life. How hot is too hot for anything to live in? How acidic is too acidic for living? The conditions that allow life to live defines habitability. If an extrasolar planet or moon has conditions, however extreme, that life has been found to live in, that place is habitable. The extremophiles and the conditions of the geothermal features at Yellowstone push the limits of habitability further than is habitable for humans. :

Extremophiles Tiny, extreme-loving microbes Bacteria & Archaea Microbes are found EVERYWHERE on Earth. Extremophiles when extreme! Yellowstone is one of the best places to study extremophiles. Variety and accessible The living things in the Yellowstone geothermal features such as boiling mud pots, geysers, and hot springs are called extremophiles because those environments are too hot, too acidic, or too toxic for most living things. Extremophiles are special kinds of microbes that live in environments that people or other animals would not be able to survive. Microbes are tiny, single-celled organisms. Students may know them as germs. Archaea are similar to bacteria but are not closely related on the tree of life. Microbes are found every little place on Earth from the top of Mt. Everest to the inside of a geyser. Microbes are the most successful living creatures by sheer number and distribution. They are only called extremophiles when the place they live is extreme. Yellowstone is one of the best places on Earth to study extremophiles. The different conditions of the geothermal features host a wide variety of extremophiles. Also, the extremophiles there are very accessible to researchers unlike some of the other extreme environments we will talk about. Synechococcus (pronounced sign-eh-co-cock-us) live in hot springs and are photosynthetic like plants.

Where can we find life? exceedingly hot in below-freezing temperatures dry deserts very acidic deep underground at the bottom of the ocean other planets? Have students name places on Earth that fit each description. These environments could be used as analogs to study other planets that share these characteristics. For instance, the life that lives at the bottom of the ocean could be an analog to life that possibly lives at the bottom of Europa’s ocean. What extreme environment on Earth would be an analog to Mars? Mars is very dry and cold. The fact that we find life everywhere we look on Earth tells us that it is possible for microbes to live on other planets or moons that have similar conditions to anywhere on Earth. What may be extreme for us on early may be considered normal on another planet or moon.

How is Yellowstone like early Earth? Around 3.5 billion years ago: only rocks, gases, water, and HOT temperatures First life to emerge: microbes Iron-sulfur compounds To study how life may have emerged on Earth, scientists must look at what is was like on Earth 3.5 billion years ago. This is about the time that Earth started having life, because scientists have evidence of microbes back then. 3.5 billion years ago, Earth was much different than today. There were no trees, grasses, or even dirt! There were only rocks and water on the surface and it was very hot. Some of the thermal features in Yellowstone match this description. There were different gasses in the atmosphere as well and some of these hot springs give off similar gasses. If you have ever been to Yellowstone you might have smelled the sulfur gas that smells like rotten eggs, this is similar to the atmosphere of early Earth. Also the only life on our planet at this time was tiny microbes like bacteria. Most of the thermal features in Yellowstone harbor microbes, when most living things could not survive in these hot and poisonous waters. Some scientists believe that iron-sulfur chemicals such as pyrite (or fool’s gold) were important to chemical reactions that formed the building blocks of life. These chemicals are abundant in Yellowstone, and if life needed iron and sulfur to make the building blocks of life, the microbes in Yellowstone could be similar to this type of life. Bacteria Iron-Sulfur: Pyrite Bacteria and pyrite from: www.thinkstockphotos.com

Where in Yellowstone are scientists doing research? Norris Hot Springs: Acidic and Toxic Metals Similar to early Earth Old Faithful: No Oxygen or Light Methanogens Grand Prismatic: Photosynthetic Microbes Microbial Mats Mammoth Hot Spings: Limestone Biosignatures Norris hot springs is acidic and full of toxic metals like iron. Scientists believe this is similar to the conditions of early Earth. The microbes there eat iron as food and could have survived on early Earth. This picture is of a probe measuring the pH of the water, and the orange color is from the microbes that eat iron. Old faithful is not only beautiful and one of the biggest attractions of Yellowstone, but it provides and interesting extreme environment for microbes. There are microbes that live inside the geyser. They are subjected to extremely high temperatures and pressure. There is no oxygen or light inside of the geyser so these microbes must find other sources of food. These microbes produce methane as a waste product. Methane is a gas commonly used as a fuel. Scientists study these organisms’ production of methane as a way to identify microbes on another planet. If scientists can tell that the methane on a different planet is produced by life, it allows us to test for life without actually going there. A chemical that tells scientists that there is something alive is called a ‘biosignature’. Grand prismatic is one of the most beautiful features of yellowstone. It was pictured in whole on the very first slide. The different colors from yellow to orange to red to green are caused by different types of microbes. These microbes produce their own food via photosynthesis, like plants. These microbes live in complex communities called mats because they are flat and layered. Scientists have fossilized microbial mats from billions of years ago. These microbial mats were on the early Earth. Mammoth hot springs has cascading white and brown terraces. These are caused by microbes that produce limestone, a type of rock. These microbes encase themselves in limestone over their lifetime and become fossilized. Scientists look at these fossilized microbes as a different kind of biosignature. If they can find rocks with the same fossilization on other planets, that is evidence of life.

Why are microbes so important to astrobiology? First life on Earth Relatively simple Very hardy Microbial Mat Microbes were the first life forms on Earth. Complex multicellular organisms were not present for billions of years. They give us insight to life’s beginnings. These tiny organisms have relatively simple nutritional needs and ways of making a living. They are relatively easy to grow and study. They evolve very quickly, allowing scientists to study how Earth and geology affects evolution. These organisms live every place on the planet. Since there are so many extreme environments on Earth that these organisms can live, scientists think they make good candidates for life on other planets. Images from: microscope.mbl.edu

What is habitability? Where can life live? Habitability is the potential for an environment to develop and sustain life. Extremophiles broaden our definition of habitable. Determining habitability in the solar system and universe Astrobiologists try to determine where life can live to help understand if life could live on other planets. If scientists can find the limits of conditions where microbes can live we can better focus research on planets and moons that fit into those limits, like Mars. Habitability is the potential for an environment to develop and sustain life. Can on organism make this place a habitat? Humans have a very narrow range of habitability. We cannot live where it is too cold or too hot, too dry or too wet, etc. Extremophiles can live almost everywhere that we can’t and allow us to imagine life living on other planets that we could not live on. After a planet like Mars, or a moon like Europa’s habitability is determined, astrobiologists can predict what type of life can live there and what conditions they would have to survive. Looking at extreme habitats on Earth like Yellowstone helps astrobiologists not only determine the possibility of how life originated, but helps define habitability of other planets. The extremophile microbes of Yellowstone may help answer the age-old question: are we alone?