How did you end up in the field you are in today? Who or what inspired you to pursue this career? Who are some of the people you look up to or admire?
Unlike a lot of scientists I know, I was not particularly aware of science when I was young. I loved nature and drawing, I was an awful daydreamer, and I was planning on attending an art school, possibly becoming an illustrator. My eighth-grade science class never caught my imagination. I guess I wasn't ready for it, because when I took a biology class in the summer before entering the tenth grade something quite magical happened. I knew that I wanted to be a scientist and a biochemist too. I have never had any doubt since.
I attended Pasadena City College where I worked in a microbiology prep lab as a student technician. I got to know bacteria up close and personal; they can be really smelly, slimy things, but often beautiful too. I went on to the University of California Berkeley and majored in bacteriology but took all the chemistry and biochemistry I could fit in too. I received my BA in 1965 and continued in the Bacteriology Dept. at Berkeley as a graduate student. My education was to continue at Ames Research Center. I was employed by Dr. Harold P. Klein. Our relationship became one of mentor and student. Our laboratory was part of what was then called the "Biological Adaptation Branch." It was full of people studying life in extreme environments. Science was definitely fun working at Ames. Dr. Klein's own interest was in lipid synthesis, that's the way cells make fat. Lipids are great things, they come in all shapes and sizes, and have an interesting property: they're amphiphilic. This means that one end of the molecule is what we call polar, it likes to be in water (it's hydrophilic), while the other end likes to hide from water, we call that hydrophobic. This is exactly what a molecule that makes up a cell membrane needs to be. It needs to be both in contact with the outside water world and to still form a barrier to keep things inside the cell. During the 70's Dr. Klein was the lead scientist for the Ames Life Detection experiment on Viking, our first mission to Mars.
Dr Klein's work with Viking left him little time for our research and I increasingly worked as an independent scientist. I studied the role of oxygen in eukaryotic evolution. A eukaryote is a type of cell like you and me. It is somewhat more complex than a bacterial cell. Almost all eukaryotes require oxygen to live…that's the element in air that allows us to breathe. Many bacteria don't need oxygen at all. We know that very early in Earth's history, over 3 billion years ago, there was very little oxygen anywhere. The bacteria loved it and were the only life forms around for a lot of years. These bacteria are called anaerobes. We thought if we could figure out how much oxygen a eukaryote needed, we would know how long it took for eukaryotic cells to evolve. I probably need to back up here and explain that very early on (more than 3 billion years ago) a group of bacteria evolved that photosynthesize. Just like the grass and trees around us, these bacteria, figured out how to turn sunlight and water into oxygen. They are called cyanobacteria. The oxygen that the cyanobacteria produced gradually filled the atmosphere to provide the modern air we breathe today. But air didn't always have as much oxygen in it as today and not all eukaryotes need as much as we do to breathe. We found that certain lipids, that play a vital role in eukaryotic membranes, need oxygen for synthesis, but very small amounts that could have been present very early in Earth's history. These lipids are sterols. The cholesterol in our food is a type of sterol.
I soon had my own lab at Ames in what is now called the Exobiology Branch, and turned my attention to a group of bacteria that use oxygen and methane to grow. These bacteria called methane-oxidizers make sterols and also another type of lipid, the hopanes. At this time I was introduced to Dr. Roger Summons. Roger worked as an organic geochemist for the Australian Geological Survey. There are just a few places left on Earth where very old rocks are still at the surface. Australia has some of the best. Roger is an expert at finding molecules like sterols and hopanes in these very old rocks. We teamed up to try to understand how long methane oxidizers have lived on Earth.
Roger and I have worked together on other projects too. One of them involved figuring out how old cyanobacteria are. Roger and his colleagues had found a type of hopane in rocks that were dated at 2.8 billion years. I traveled to a place where cyanobacteria still grow much as they probably did on early Earth: Yellowstone National Park. Most eukaryotes can't live in hot water, but many bacteria can. The hot springs in Yellowstone provide an ideal environment for cyanobacteria to grow. I worked at Yellowstone with my colleague (and fellow JASON researcher) Jack Farmer. Jack showed me all the interesting different mineral environments in Yellowstone, each with their own distinct types of cyanobacteria. I isolated many different cyanobacteria from these hot springs and found many made the same hopane as found in the ancient rocks. This is how we were able to say that cyanobacteria were at least 2.8 billion years old, and that's how we know that oxygen producing photosynthesis is that old.
When we find a natural environment like Yellowstone where simple life forms like bacteria are still the major players, we call it a microbial ecosystem. There are hundreds of different types of bacteria in an ecosystem, not just cyanobacteria. They help each other out just like we do in our communities, but they are communities made up of bacteria. These bacterial communities are what we think lived on early Earth and probably on Mars too. We try to study them here on modern Earth to learn about our planet early on and how these bacterial communities helped change the oceans and atmosphere. This helps us to know what to look for on Mars.
In the late 90s, NASA started a new program called Astrobiology. My former boss, Dr. Klein is considered the father of the Astrobiology program, so of course, I am very proud to be a part of this program. A group of scientists here at Ames and at several universities are working together as a team on a new project in Astrobiology. We want to understand another type of microbial community; one with layers of different bacteria living on top of each other that we call a microbial mat. These mats live in a hypersaline environment. Hypersaline means very salty water. Our mats live in ponds with about three to four times as much salt as seawater. We know from the Mars Exploration Rovers, Opportunity and Spirit, that very salty oceans were once present on Mars. We want to know what kinds of bacteria might have lived in a salty Martian ocean and whether interesting molecules like sterols or hopanes might survive in the Martian rocks like they do here on Earth. I am working on this project with Dr. David Des Marais, who was one of the scientists involved with controlling the Mars rovers from JPL. Dave is a biogeochemist here at Ames and the leader of our Astrobiology program.
What Mars-related research/work projects are you currently involved in? How do you conduct your research/work and what tools/technology do you use? How does math factor into your work?
I am a microbiologist that analyzes lipids. I study bacterial and microbial ecosystems that serve as analogs for early Earth and Mars. To put the whole picture together, we need many lines of evidence and so we work as a team: microbiologists, geochemists, hard-rock geologists, molecular biologists and many more. Different types of bacteria have different lipids. The techniques we use to analyze lipids involve lots of organic chemistry to isolate molecules. We use liquid chromatography and gas chromatography to separate these molecules. We use a mass spectrometer to fragment the molecules (it forms distinct fingerprints) so that we can determine their structure. We also measure the amounts of carbon isotopes, carbon-12 and carbon-13, using an isotope mass spectrometer. The isotope ratio of C-13/C-12 in a molecule can tell us whether it is made by biotic or abiotic processes. Our instruments are run by computers and software that collect the data. Much of the math is done by the software, but it is important to understand how it works so you can figure out if it is working well or not. Our instruments provide us with lots of numbers and we need to be able to do some fairly elaborate calculations that involve algebra and calculus. We also need to be able to manage our numbers in software spreadsheets like Excel.
What do you like best about your job? What do you like the least? What are the most common misconceptions that people have about what you do?
What do I like most about my work? I love to learn new things. Doing research you get to figure new things out. You're the first to know something new about how things work. That's great. I also love to share this with my colleagues and anyone who will listen to me.
What I like least: paperwork. There is a lot of paperwork involved in putting together a laboratory and keeping it running. Sort of like doing your taxes. I'm not fond of that either.
Misconceptions: well possibly that science, particularly space research, isn't important to the everyday life of people. People need to look around themselves at everything that makes our world work and ask the question, what would life be like, what will life in the future be like, if some young person doesn't decide to solve the problems that will make life better in the future?
Where have you traveled for your work? What's the favorite place you've been so far? What was the strangest or most incredible thing that happened to you while conducting your work?
I have a special fondness for Yellowstone. It is a magical place for a microbiologist. On my first field trip there in 1994, late in the afternoon, I had walked in to a hot spring some distance from the road that I planned to work at the next day. I just wanted to look things over and make my plans for the next day. There was a rumbling up in the trees surrounding the spring. No it wasn't bison or a bear. Tramping down the hill out of the woods was a party of newsmen, cameras and sound equipment to boot. They had come in search of a "real scientist." There was no way I could just excuse myself and return to my contemplations. I found myself being interviewed for the ABC Nightly News. I never actually saw the show; I was busy working in the field, but many friends and relatives called to tell me that I was now famous -- a real Yellowstone scientist.
What were your favorite books as a kid? Why?
My mother encouraged me to read and took me regularly to the Pasadena City Library. There was a children's reading room, I understand that it is still there. I read many books during the summer especially. I don't remember them all, but there was one series of adventure stories that I was particularly fond of, Miss Pickerell, especially Miss Pickerell Goes to Mars. I need to see if this book is still around, I might want to read it again.
What was your favorite subject when you were in middle school?
My favorite class was Art. I loved to paint and draw. But I also must have liked math. We were required to take math in the 7th and 8th grades. I can't say that I was a particularly good student, but my 8th grade math class was a disaster. The class was unruly and no one learned much. Although I passed, I don't think I learned much and I decided to take a remedial class in the 9th grade. That was one of the best things I ever did. I had a great teacher, Mr. Mull, he taught me to love math. Numbers are sort of like art, full of patterns and designs.
Why do you think it is important for students to make comparisons between Earth and Mars, and what can we hope to learn by doing that?
Earth would appear to be a very special place. Many now believe that early Earth and Mars were similar in many ways, and that life may have originated on both planets. This opens many questions about potential life on other planets and beyond our own solar system. There is also the potential that subsurface life may still exist on Mars. There is probably no greater philosophical challenge to mankind than to understand our origin and to protect the planet of our origin. To do this, we must understand the delicate balance between life and our biosphere. We must fully understand the process of planetary evolution. For that we need to know what happened on Mars.
What one thing would you most like students to learn from participating in JASON Expedition: Mysteries of Earth and Mars?
I hope students will understand that Earth is a very precious planet. Both Earth and Mars have evolved since their formation. Biology has had a major role in the transformation of at least Earth. Life may have evolved on both planets. One is now our hospitable home; the other is probably a dead planet. We need to know why.
What advice would you give to students who are interested in studying science?
Astrobiology encompasses just about any science discipline that you can think of, including the social sciences. Most important is a good general education in both the sciences and humanities. There will be a lot of elements to any career in science (writing, personal relationships, etc.) and a well-rounded person will have a better chance to succeed with all challenges.
When you are not working, what do you like to do for fun?
I take care of my cats. Love to garden and cook, especially the things I grow. I have enjoyed many activities throughout my life including skiing, backpacking, photography and painting.