Friday, February 14, 2020

Earth’s Earliest Signs of Life: If we found it, could we recognize it?

Ancient biologically-formed, 2 billion year old rocks; Marilyn, Richmond Gulf, 2011

         Since the early 1970s, scientists have been measuring the amount and nature of organic carbon from almost 4 billion-year-old Precambrian rocks. Geologists searched the world over for older and older rocks resting exposed on Earth’s surface that might contain evidence of the first signs of life. Greenland’s coasts have a couple of small outcrops with some of these oldest rocks. For example, the Isua formation was thought to have formed in a sedimentary environment 3.85 billion years ago. Not everyone agrees these were originally sedimentary rocks, however. The other outcrop—the Akilia formation—is very small in scope with similar disagreement as to the rocks’ origin. In far northern Canada on the shores of Hudson Bay, a third very old section of rocks with a nearly unpronounceable name of Nuvvuagittuq is also thought to be almost 4 billion years old. These ancient rocks are important because they hold clues to the origin and timing of life on Earth—something critical to searching for life on other planets or moons. If we can’t find the necessary evidence of life here on Earth, how will find it using rovers on Mars or spectra of far distant extrasolar planets?
         In the 1980s, Cyril Ponneperuma and his student, Cliff Walters, of the University of Maryland, examined the organic geochemistry of the Isua rocks to find evidence of the first living organisms. Professor Ponneperuma wanted Cliff to discover something revolutionary. Cliff struggled at the University of Maryland to find any molecules that did not look like modern contamination, but his professor pressured him to “discover” something big. Fortunately for Cliff, he sought out the wisdom of Geophysical Lab’s Tom Hoering. Hoering’s reputation for careful, exacting work was well known in the geochemistry community, particularly after he debunked an earlier study on “Precambrian” hydrocarbons, which turned out to be ink from the newspapers wrapping the rock specimens. Walters, working with Tom, finally concluded that any molecular signals in these samples were contamination. He went on to become a very successful petroleum organic geochemist at Exxon Mobil, having learned from Tom Hoering about stringent lab procedures.
         A decade later, UCLA scientists used more sophisticated instrumentation to measure carbon isotope signals directly in the rocks (i.e. in situ) with an instrument called an ion probe, a multi-million dollar combination mass spectrometer and microscope.  A beam of strong ions, charged particles, bombard the polished surface of a rock sample. Elements from the rock are sputtered off the surface then accelerated through a high vacuum flight tube where they are separated in a strong magnetic field and then counted by ultrasensitive electronics. The ion probe was promoted as the solution to answering the question of whether the carbon in ancient rocks was indigenous to the sample or was caused by contamination later in the rock’s nearly 4 billion year history. The UCLA group measured carbon isotope signals in Isua samples, concluding that they were in the range of similar measurements from much younger samples that every one in this scientific community agrees are formed by living organisms.
Stromatolites, Belcher Islands, Canada, 2011

         The problem with the ion probe measurements is that there were no comparable carbon isotope standards by which to compare the carbon isotopes of the sample. As time went on, ion probe users realized they needed to be much more careful about how their instruments were standardized. At the Carnegie, scientists there worked on this problem and solved it by testing a suite of rock types by conventional isotope techniques with measurements made by the ion probe. This is now standard protocol. Dominic Papineau, a postdoctoral fellow at the Geophysical Laboratory in the mid-2000s, used this approach for accurate and precise carbon isotope analyses of the Akilia rocks from southwestern Greenland.
         Dominic Papineau, a French Canadian, was a graduate student at the University of Colorado training with Stephen Mojzsis, the senior author on the original ion probe paper while he was a student at UCLA and now a professor in Colorado. Steve Mojzsis has quite a reputation for speaking his mind at scientific conferences. A bright, well-spoken man, he can argue a point with great skill, which he does. Dominic wrote to me midway in his doctoral work and asked if would be on his dissertation committee. I readily agreed. Dominic, learning from his professor, tried to emulate Mojzsis, but as a student, he wasn’t ready to take on senior scientists in public. Papineau came to the Geophysical Lab as a postdoc working with me and opened many new doors for research and collaboration. With a bit of a swagger, he worked hard trying to deal with opinions and speculations about the Earth’s oldest rocks. Unfortunately, Dominic has a reputation in the community that is tainted by a scandal that he was involved in during a field trip to Canada that Dominic led for Boston College students in 2012. He was able to prove his innocence, but he lost his position at Boston College and is now working at the University College London. I stood by him during this difficult time. We remain colleagues to this day. 
Dominic and Marilyn, Canada, 2011

         As Dominic began his studies on the Akilia rocks, I became aware of all of the strong opinions and controversies with these particular samples. Several authors published on the Akilia “rocks”, however, there are only a handful of specimens from this location and no real outcrop that can be studied by the community. Therefore, few samples can be shared among labs.  Speculation and debate about what type of rocks these are and how they were formed abounds. Dominic obtained a couple of the Akilia specimens from his PhD advisor Stephen Mojzsis and we entered the scientific fray. My first paper with Dominic and Steve was based primarily on microscopic analyses using Raman spectroscopy, transmission electron microscopy, and Synchrotron X-ray based microscopy, all highly technical instruments available at national and high-end scientific research labs like the Carnegie. In this paper, Papineau studied graphite, a high temperature pure carbon form, found in association with apatite crystals, phosphate minerals common in many types of rocks.
         Andrew Steele and I encouraged him to quantify the occurrences of graphite-apatite pairs rather than loosely describing them. Were their common features? Were there only one or two within a thin section? Did they all look the same? Papineau found that about one-sixth of the apatite crystals were associated with a graphite coating. Raman spectroscopy determined that the graphite in these rocks was crystallized at very high temperatures (>650°C) during metamorphism in the deep Earth. The carbon was severely altered in its composition making it impossible to determine if it was originally made by a living organism or from non-living, geological processes that produce the thick deposits of graphite that is mined to make pencils.  In a second publication with these samples, we found that the carbon isotope patterns were quite different than the earlier ion probe measurements. We were stuck concluding that we were unable to pin a biological origin to the graphite in these old rocks. It was a disappointing, unsensational conclusion, but correct. Papineau had gone the extra mile to produce good primary data. As we learn more, perhaps there will be a new instrument to provide a more definitive answer as to whether life originated 3.85 billion years ago or much later by 3.5 billion years ago.
         While doing this research, I learned first hand about “having a dog in this fight” as it refers to scientific findings. With very few exceptions, for example, the majority of scientists understand global climate change. Non-scientists might still have some doubt, but for me this is “settled” science. Early Earth scientists can be very opinionated and have no problem arguing one way or another about when life arose on Earth. They have “dogs in the fight.” I remain hopeful that as new techniques are developed the community will come together.

Traveling the world to find old rocks
         The work with Papineau took me to several locations around the globe to examine Precambrian rocks in the field. We traveled to Ontario and Quebec to study banded iron formations (BIFs) on a NASA Astrobiology Institute -sponsored field trip in which a diverse team of scientists argued in the field about the levels of oxygen on early Earth, formation of band iron formations, and isotopic compositions of billion-year-old rocks. One memory I have of this trip is of geologist Dick Holland, a distinguished professor at Harvard University, and Hiroshi Ohmoto, a strongly opinionated professor Penn State, standing on a BIF and speaking into a bullhorn to young astrobiologists, to give their perspectives on all of these topics. 
Marilyn and Verena Starke, Canada NAI trip

         My next trip with Dominic was to Rajasthan, India, where we sampled stromatolites containing commercial grade phosphates from the Aravalli Supergroup. I arrived in India via Mumbai airport and was immediately staggered by the density of human beings. Traffic moves in both directions even on separated freeways! Trash is everywhere—in scared temples, in fancy neighborhoods, as well as places with shacks made out of sheet metal and cardboard. Open pit mining, which has largely disappeared in much of the United States, was happening in every town we traveled through. On the plus side many people, even in dense cities, had small vegetable gardens.  We were frequently invited into people’s homes for tea, something rarely done in America. Food was outstanding. My only gastrointestinal challenge came from eating at a deserted, tourist restaurant. The rock outcrops were spectacular and no one bothered us.
Himani Chobisa, my assistant, and Marilyn, India 2009

         This trip to India and my first in-depth field trip to examine stromatolites in a natural setting was a remarkable experience. Standing on outcrops that extended for several kilometers and that had been formed almost entirely by the actions of microbes was a highlight for me as a biogeochemist who was brought into the field by the early work of Barghoorn and others from the 1970s. My challenge was to inspect the rocks in the field and couple observations with my more reductionist approach based on isotopic measurements in the laboratory. We traveled with two Indian specialists, Professor Roy and Professor Ritesh Purohit, who had studied the geology of these formations for many years. Based on the samples we collected from India, we published a series of papers on the development of the Earth’s early nitrogen cycle. Based on these 2.15 billion years old samples, we linked the carbon cycle to a robust nitrogen cycle at the time when atmospheric oxygen increased 2.4 billion years ago. Microbes, primarily cyanobacteria, were the producers of oxygen at that time. Not only did we measure high concentrations of organic carbon in these rocks, but their carbon isotope values were highly variable. Extreme variability in carbon isotopes is indicative of swings from low to high primary productivity by photosynthetic organisms. 
Himani and  Marilyn, in the airport, 2009

         Fieldwork in India, as well as in Ethiopia, was never conducted without close watchfulness from local people. Working in India was a different experience than Australia, Belize or Svalbard. The absence of personal space in India was something I’d not experienced before. People carried out their “bathroom” activities on the side of highways, as an example. When we were collecting rock samples, folks did not ever interfere, but they were within a few feet of where we were working. At the end of a 1 to 2 hour sampling, our field area would be lined with about 20 to 30 men, women, and children along with goats, water buffalos, and cows observing our activities.
Field work in Rajasthan, India 2009
         My second major field trip with Dominic Papineau was fascinating for its spectacular geology, the remoteness of the location, and the chance to interact with native people of northern Quebec. From a small village on the eastern shore of Hudson Bay we chartered a fishing boat, the Kakivak, in July 2011, that was crewed by Inuit men. My husband accompanied me and 13 other scientists along with five Inuit crew for a two-week adventure on Hudson Bay. We set sail from the small village of Umijaq on a Sunday afternoon, making our way across the Bay to the Belcher Islands.  These islands are special for several reasons. First, they are very remote, and scientists have visited them only sporadically over the past 100 years. Robert Flaherty described the geological formations in 1918. Our target samples were 1.875 billion-year-old stromatolites that had first been found in the early 20th century. Scientists at that time realized how special these rocks were and found evidence for the remains of microorganisms that lived on the early Earth. We returned to several of these sites, spending three days at one of the most spectacular stromatolite sections that I have ever seen. 
Loading the Kakivak in Umiaq, 2011

         Second, the islands are special because they are biologically pristine. This was the second time I was able to study and sample tundra vegetation. As the temperatures of Arctic and tundra areas increase due to climate change, plants will respond with longer growing seasons, making it important to develop records of present day communities and the processes that influence them. I was able to collect about 75 specimens from the Belcher Islands for my herbarium collection that may—some day—serve as an historic record of what the plant life was like in the early 21st century.
         People other than the Inuit rarely visit the Belcher Islands, as there is little to no support for ecotourism in the area. We were fortunate to be able to experience Inuit culture including native fishing. Periodically, the crew fished while we were out examining rocks. They caught Arctic char which they shared with us: the muscle, Canadian sushi, went to the scientists and the rest of the fish--tongue, liver, intestines, skin, heart--was consumed raw with great relish by the crew. The Inuit understand in a very fundamental way the ecosystem in which they live.
         The second week of our expedition took us back toward the mainland. We traveled to the Nastapoka Islands that form an arc parallel to the coastline, a part of the Hudson Bay considered by some to be a remnant crater from a meteorite impact. Our scientific party scoured several of these islands looking for evidence of shocked rock strata indicative of such an impact. We were unable to find samples of this nature, but could see correlations between these rocks and those on the Belcher Islands. Our third destination was the Richmond Gulf, an unbelievably beautiful body of water with high mountains, cliffs, and crystal clear waters. Our team scoured at least 7 different sites with numerous outcrops to compare the stratigraphy here with that on the Belcher Islands. Canadian Geological Survey scientist Wouter Bleeker took samples for dating, as there are only a handful of dates from this whole area.   
Chris, Wouter Bleeker, Marilyn--after two weeks of no showers
         In the Richmond Gulf, we were treated to a sighting of beluga whales, small white whales considered a delicacy by the Inuit. The pod of about 20 belugas swam into the inlet where we were moored, diving, jumping, and hunting for the abundant Arctic char. Our Inuit crew watched them carefully, but decided not to hunt owing to the fact that we had 15 people on one small boat.
         Almost 600 kg of rocks were shipped back to the United States and Ottawa for further analysis. The expedition was a lifetime experience for all of us, as we were privileged to seeing places, rocks, and people that very few people will ever have the opportunity to experience. The results from this trip are currently being written up for a publication, spear-headed by Papineau, on the nature of concretions found in Paleoproterozoic rocks and what they mean in terms of organic carbon cycling.
         Studies on isotopic compositions of Earth’s earliest sedimentary rocks are going to feed into studies that will consume the astrobiological community when samples from Mars are finally returned to Earth. It is vitally important for the scientific community to continue to carefully study biosignatures on the Earth weighing what is a definite biosignature versus an ambiguous one.  The personalities that study Earth’s oldest rocks are strong and hold strong opinions. There is a constant push and pull to announce the first evidence of life on Earth, similar to the desire to find the signs of life on Mars.

Tuesday, February 11, 2020

Bringing the study of Astrobiology down to Earth: Arctic Mars Analogue Svalbard Expeditions (AMASE)

The Babes of Science: Marilyn, Pan Conrad, Liane Benning

         Since the emergence of the field of astrobiology in the late 1990s, fundamental questions still persist even today. What are the basic characteristics of life? How do we recognize life if it does not resemble any known life forms on Earth? These questions have been long debated by National Research Council committees, NAI teams, and numerous panels of distinguished scientists. Living organisms are essentially never in static equilibrium with the environment. They exist in steady state, maintaining a balance between growth and decay, or actively growing. An environment that is neither too hot nor too cold where complex molecules can exist without being vaporized or frozen is needed to sustain life. That environment should have a liquid, presumably water, to enable biological reactions. Finally, there needs to be some system for allowing for evolution.
         In 2000, I helped organize a workshop sponsored by the National Research Council and we wrote the following:

“We make the assumption that if life exists on other planets or moons, it will be carbon based and dependent on liquid water...Carbon is the best element for creating macromolecules; it can form chemical bonds with many other atoms to produce biochemical complexity. All life on Earth evolved from a single type of cell, referred to as the last common ancestor, and thus shares the same genetic code and central biochemistry. Extraterrestrial life could be so different from life on Earth that modern methods would fail to detect it.”

         Our challenge was to find evidence of life in the most extreme, seemingly barren places here on Earth. We astrobiologists were on the search for life as we don’t know it. My efforts started with the AMASE expeditions, beginning in 2002, with Hans Amundsen and Bjorn Jamtveit of the University of Oslo as leaders. They had assembled an international team of scientists and expedition artists for a voyage to the northern islands of the Svalbard Archipelago. Svalbard, covered with ice sheets and glaciers, is located at about 80° north latitude, the same latitude as northern Greenland. Northern Svalbard is an Arctic desert, which was one of the principal Mars analogue traits important to our studies. It is serviced by flights into the major town of Longyearbyen, a combination frontier and tourist destination visited in summer by people from around the world. Like Mars, Svalbard is cold, dry, and virtually devoid of biomass---with exposed rock formations, as well as thermal springs and dormant volcanoes, all-important characteristics for our study.
         My Geophysical Laboratory colleague Steelie and his student Maia Schweitzer were invited on the 2003 trip. Steele was a novice field scientist, having worked primarily in the lab on experimental studies. Steele and Schweitzer brought back interesting microbial samples and rocks from Svalbard volcanoes to examine for traces of microbial life and organic carbon concentrations.
         In the laboratory, I began to engage in the analyses of those samples finding small amounts of carbon and nitrogen in rare rocks called xenoliths—“strange” rocks from deep within the Earth’s mantle tens of kilometers underground. The 2003 team also brought back special carbonate samples, some of which were precipitated under glacially cold conditions. I measured the isotope patterns in these rocks giving the AMASE researchers information they wanted. Hans Amundsen visited the Geophysical Laboratory in December that year and learned that I had a viewpoint that had not yet been considered. Not only were stable isotopes key for all the samples we collected, but also, as a biogeochemist and geo-ecologist, I could bring a different perspective to sampling a Mars-analog site. I was therefore invited to participate in the AMASE 2004 expedition the following summer.
         The Geophysical Laboratory group in 2004 consisted of Andrew Steele, Maia Schweitzer, Jan Toporski and Jake Maule (Steele’s postdocs), Verena Starke (Steele’s graduate student), and me. The Director of the Geophysical Laboratory Wes Huntress, former NASA Associate Director and champion of the Astrobiology program, provided special support for us to participate in the expedition. We took with us to Svalbard numerous small items of equipment to measure nutrients and find bacteria in the field. We brought boxes of 50 ml plastic test tubes, sterile sampling gear, rock bags, chemical reagents, and rock hammers. Our personal duffle bags were full of winter clothes, hiking boots, thick socks, down jackets, and long underwear. Our departure from Dulles International Airport was complex because of extra bags and the remote destination in Svalbard. Miraculously, we all arrived in Longyearbyen with our scientific and personal gear ready to meet other AMASE participants and train for the voyage to our field sites.
         For most of my life, I abhorred cold weather. The thought of heading to one of the coldest regions of the Earth was something that had never appealed to me. Summers in the high Arctic can be very pleasant, however, depending on the year, with daytime temperatures requiring only a light jacket. Alternatively, a freak snowstorm can blow in, plummeting temperatures far below zero. In 2004, by the time I left for Svalbard at 80° North latitude, I was very excited to be immersed in this cold, remote landscape. I couldn’t wait to board our ship, the M/V Polarsyssel, and head out to the gray Arctic Ocean.
         After arriving in Longyearbyen, we settled into the local hostel, tested our equipment, purchased more Arctic-worthy gear, and learned about rifles and polar bears. Polar bears are the top carnivores in the Arctic. Typically, these bears spend much of their time on the ice pack hunting seals, but in the summer, when the ice pack melts, the bears move onto land, give birth to their cubs, and do most of their hunting near shore. Polar bears are a protected and endangered species for a number of reasons, but polar bears and humans should not mix. The AMASE team went to the University Centre in Svalbard (UNIS) rifle range to learn how to protect our fellow scientists and ourselves if we did have a close encounter with a bear. Fortunately, I grew up with a father who was a hunter and taught me how to shoot a rifle, albeit a rather small one, at targets. The rifles we had in Svalbard were German Mausers, comparable to 30-06 rifles in the United States. They were heavy and manually operated; automatic weapons are banned in Norway. We learned loading and unloading of ammunition first, then the three positions for firing.
         Our group of about 15 was splayed out on our stomachs, the first shooting position we learned. The rifles had a substantial kick to them, and it took a steady hand to control the rifle as the shot was fired. We each fired off a round of 4 bullets at the target, learned to carefully check our weapon to see if it was emptied of bullets, and laid down the guns. Our trainers checked the targets. I hit mine every time--not in the center, but in a respectable area that may have been lethal. Our second position was kneeling, which required greater control of the heavy rifle, but improved our ability to aim it properly. Finally, we learned to fire the rifle standing up, the most comfortable pose, but also requiring attention to detail and a strong stance. My aim was decent and I passed the test to be able to defend myself and others from polar bears. Of course, we all hoped we would never have to actually fire the gun at a bear.
         We departed from Longyearbyen about a week after arriving in Svalbard. Our vessel in 2003-2005 was the M/V Polarsyssel, an icebreaker once owned by the Governor of Svalbard, and now available for hire. It was an older ship, not fitted out for scientific study. Our “laboratories” were set up down in the cargo bay area in tiny rooms about 2 meters by 2 meters. I had the luxury of sharing my lab space only with Steelie’s student Verena, but Steelie and his other colleagues—most of them very large men—were crammed into a similarly sized space. Our cabins where we slept were on the next floor up with two of us to a room and very comfortable. Verena and I also shared a cabin, which was kept extremely neat according to her German nature. I couldn’t say the same for cabins shared by the men. Hans’ stateroom was on the upper deck with a living room, en suite bathroom, and separate sleeping quarters. There was a common room on the level with the galley and the mess area where we met to discuss our daily plans. Outside, the back deck was designed as a helicopter-landing pad, which we used for changing our scientific crew midway through the expedition.
Heli-deck on the Polarsyssel

         Once we came aboard the ship and unloaded our gear, we underwent our next training on how to don survival suits and learn “man overboard” drills. The bulky orange suits made us feel like monsters, and we laughed as we put the giant Norwegian sized suits on and hopped around the deck of the ship. When at our field sites, we wore these suits as we traveled to shore in zodiac boats. In ten years of AMASE expeditions, we never had a serious safety issue in the field.
         Leaving the Longyearbyen harbor—and civilization—always brought everyone on deck and a tingling sense of adventure. We left behind the hotels, restaurants, and tourists bound for isolation and adventure! The passage north to our field areas took about a day and a half, often in fairly rough seas. The voyage gave us time to set up our labs, get used to shipboard life, and plan our first Arctic explorations. 
Leaving Longyearbyen harbor

         By far, one of my favorite places on Earth is Bocfjorden with the view of Sverrefjellet volcano towering over the fjord. A mountain is an ecosystem unto itself. Its northern flanks host more cold tolerant organisms. The southern flanks are drier, as are the higher elevations. Over the years, I made multiple trips up its flanks and down into its gullies. The feeling of being on top of the world is strong everywhere on the volcano, not just the summit. Wherever I turned, I saw new plants, encrusted lichens, interesting rocks, all of which opened up new ideas for searching for life on the planet Mars. What to collect, label and store in my backpack was nearly an overwhelming challenge. At the end of a foray on Sverefjellet volcano, I would sit on the deck of the ship with a beer, realize how small I am, and strategize how to understand and sample its most interesting features.
         Over the years, I sampled ice caves, Martian-like carbonate globules, a full suite of Arctic plants, soils, dozens of xenoliths, polar bear poop, bones, feathers, lichens, and mosses. Svalbard’s ecosystems were too vast for me to collect everything I was interested in. I had to be satisfied with what I could sample in this wild terrain. It was the first mountain system that I’d studied, and I learned a tremendous amount including the basics of mountaineering. Not only did I previously avoid cold weather, I was slightly afraid of heights. As I hiked up the mountain, which had no established paths or trails, I instinctually hugged the ground, and consequently slid backwards in especially steep areas. Hans Amundsen watched, and gently suggested that I try standing up straight, letting gravity keep me upright. It worked, but required mental energy to do something that felt “wrong.” Eventually, I could make it to the top without falling. Coming down was another matter. 
My favorite volcano--Sverrefjellet, 2004

         I planned to sample plants, soils, and rocks every 50 meters from the top to the lower flanks. With a team of five colleagues, we headed downwards. The first several stops were flawless—the team collected, bagged and described specimens. About 150 meters down on one of the steepest slopes, we passed over a patch of ice covering a talus slope with small volcanic rocks. I slid, fell forward, did a complete 360° flip and landed on my backpack, sliding 15 meters downwards. My team members were open-mouthed, shocked. Because of my thick warm clothing and pack, I landed without injury, but I was shaking, grateful to be without injury. It took a few minutes, then I called this was a sample “station” and collected specimens on my rear end.
         The 2004 field season determined largely how the team would expand and contract into the future. Hans Amundsen, a descendent of the famous Norwegian explorer Roald Amundsen, is a tall, blonde, commanding figure with a penchant for charging up mountains, whacking rocks with a huge hammer called “Thor,” and uproarious laughter. It was his vision and persistence that got AMASE started and rolling for ten years. AMASE expeditions always included strong European and United States components, a mix of scientists and engineers, field and lab enthusiasts, and a blend of senior and more junior scientists. In addition, Hans always included safety personnel and often invited media (e.g., television, radio, newspaper) folks along to document the trips. We were joined by Kjell Ove Storvik, the expedition photographer with many years of experience working in the Arctic with novices. Ivar Mitkandal, then a graduate student at the University of Oslo, was raised in the Norwegian mountains, was a hunter, and provided not only sage advice on safety, but also great insight into the geology.    
Hans sampling the Ice Cave, 2004

          Our primary goal was to characterize the environment in terms of what a Mars analogue site should look like. From the geologists’ perspective, easy access to rocks from all ages and types--Precambrian to modern sediments, and volcanic, mantle rocks to sedimentary rock strata---was a strong positive reason for choosing Svalbard as a field area. Specific locations were primarily selected in terms of the type of geological outcrops we could readily sample. From the ecologist’s perspective, fewer than 200 plant species occur on these islands. All of them need to reproduce and grow in a very short summer. Animal life was limited to abundant seabird breeding colonies and migratory shorebirds. A few land birds (e.g., ptarmigan and Snow Bunting) occupy Svalbard year-round. Soils were typically only a few centimeters deep. In some places, there was only bare rock.

Our daily 24-hour routine

         The sun never sets in Svalbard in summer. It travels in a 24-hour circle in the sky not quite reaching directly above and of course, never dipping below the horizon. The 24-hour daylight was good for long working days, but the AMASE scientific team had a tendency to stay up to all hours of the night--3 or 4 a.m.--then have difficulty arising for the 7:30 a.m. breakfast call. I was usually one of the first of the scientific team to wake up and go to the mess hall for a cup of coffee. This was a quiet time to chat with the crew, the cook, and the captain. I would wander into my “lab,” maybe finish off an analysis or two, and then see who had come for breakfast. Often it was only one or two others.
         I became the unofficial “alarm clock”, knocking on all stateroom doors, opening them up a few inches, and shouting, “Get your ass out of bed!”

I wrote some lyrics sung to the tune of The Star Spangled Banner:
“Get your ass out of bed,
or you’ll wish you were dead,
cause what’s coming up next
is Morton upside your head!”

         Morton, a senior deck hand, is a giant, strong, irreverent Norwegian man well over 6.5 feet tall. On our first trip with him, he thought we were a bunch of sissies. When he took us ashore in the zodiac boat, he made a point of ramming it hard onto the shoreline. He delighted in picking us up and squeezing us in uncomfortable bear hugs. When our voyage was over and we were back in Longyearbyen, Morton consumed many shots of aquavit and sought us out for “loving” torture. We’d worn down that brusque behavior, and by the second year, he welcomed us as eagerly as we welcomed him with gusto. On our third voyage together, I treated his injured, infected toe in my role as Chief Scientist and First Aid provider. When the captain heard of this, he was puzzled why a scientist would treat a crewmember. He eventually learned that on AMASE, we were one big Arctic family.
         Breakfast consisted of a spread of Norwegian cold cuts (meats), rather bland cheese including geetoast--a molasses colored sweet cheese spread, blood sausages (delicious), tomatoes, cucumbers, and occasionally fried eggs. At every meal, we were presented with smoked fish products in bowls or in tooth paste-like tubes that you squeezed onto thin, unsalted crackers. There was always bread, jams, and peanut butter to supplement the meal. As the AMASE team straggled in, the level of conversation grew with excitement for the field day ahead.
         A small management team of Hans, Steelie, Liane Benning, Pan Conrad (JPL scientist), and I met briefly at 8:30 am, often on the ship’s bridge to coordinate with the crew. Liane, Pan, and I were known as the “Babes of Science” and over the years we inducted other women into our small, but important group. Hans and Steelie were wise enough to realize they needed a few extra people to bounce ideas off of. Liane, now a senior scientist and professor at the University of Potsdam, participated from the get-go with Hans and his colleague Bjorn. At the time, she was a mid-career professor at the University of Leeds, smoked cigarettes like a chimney, and a no-nonsense scientist. Pan Conrad, a more recent PhD, but of similar age to me, has a flair for the dramatic, a background in classical opera, and a wicked sense of humor. I filled the role as “senior lady”, an ecologist and life scientist, and “mother” of all onboard. We “Babes of Science” were usually listened to and generally respected, which was important in the male-dominated culture on AMASE.
         After our meeting, we piled down to the “day room” where Hans outlined the daily plan and decided who was going where, with whom, and when.  Steelie served as Chief Scientist once we received NASA funding. Typically, there were two to three teams going to places for science sampling, discovery, or instrument testing. Each team was assigned a safety person, who was Hans, Ivar, or one of us who had successfully shown we could hit a target with a rifle. The AMASE photographer Kjell Ove was assigned to one of the teams. After this brief meeting, we scrambled to our labs loading our daypacks with supplies, making sure we had sufficient warm clothing for all types of weather. We packed a lunch, hot tea or cocoa, and assembled on deck with our survival suits on, ready to board a small boat heading to shore. Once on shore, we unzipped the bulky orange suits, put on our boots, checked our rifles, radios, and flare guns, shouldered our packs and set off.
         Because of the eternal daylight, teams often stayed out for 12 or more hours if the field area was remote or if we were conducting timed sampling or difficult measurements. Most often, teams called for pickup around 6 pm, in time to stow samples on board ship, and change for dinner. Depending on the cook, dinners were a highlight of the day. Before embarking from Longyearbyen, we had all stopped off at the liquor store and packed in wine, beer, and the occasional bottle of gin or aquavit. Generous “senior” scientists often brought a bottle of red wine to the dinner table to share. We discussed the day’s exciting discoveries, commiserated over broken instrumentation, and argued about all sorts of topics in astrobiology, space science, and NASA-European Space Agency relationships.
         After dinner, everyone went to their labs and began evening analytical sessions. I extracted nutrients from rocks with chemical solutions, measured their concentrations, labeled and dried samples, wrote more detailed field notes, uploaded data to my computer and graphed it, and thought about the next day’s work. Others tweaked their instruments, fixed broken power supplies or cables, took spectra, and wandered between labs sharing samples and ideas. By about 11 pm, some called it a day and went to bed, others assembled on the deck with another beer, or headed to the upper deck to bask in the makeshift hot tub on the R/V Lance, the ship we took out after 2005. It was a tricky time of day. When Norwegians take the cap off a whiskey bottle, they typically throw it out, meaning that the bottle is passed around until it’s empty. Sometimes it was a challenge to keep things “between the navigational beacons” so to speak. What happens in Svalbard stays in Svalbard.
         Every year new people joined the AMASE team and were “treated” to a series of fun and demanding challenges, some of which could have been considered hazing. My first year, several of us were locked into cages designed for lifting equipment into the hold of the ship. We also had to write the lyrics to songs, create a play for presentation, and make fun of the “old timers.” In 2005, my second year, Liane Benning and Verena Starke invented my role as Queen Thora, a mythical Norse Queen who ruled the Arctic. The AMASE crew was assembled on the deck of the ship and I entered with a retinue, and read some cryptic Norwegian passages, which put the native speakers in stiches with my lousy pronunciation. I then gave the orders for the newbies and the schedule they had to adhere to. When I wasn’t on the expedition, Dave Blake took over this role as Father Dave, a stern, but hilarious “priest” giving penances to the flock.

Science Targets
         Target areas for investigation were set before each year’s expedition. For the instrument engineers, there is every landform and slope imaginable, often within easy walking distance from shore. With many rock types, cold weather, and remote electronic access, the Svalbard environment put lab-designed instruments to a realistic test. All of the team was intrigued by the presence of glaciers, permafrost, Arctic rivers, and sea ice. The polar regions of Mars contain water ice year round. Learning how to look for signs of life in snow and ice became a major focus in subsequent years. Svalbard is cold enough to contain ice caps, laminated ice that has existed for hundreds if not thousands of years. Two geothermal environments, Troll and Jotun Springs, are the most northern thermal features on land. Troll Springs built significant calcium carbonate (travertine) deposits forming terraces that extended over several hundred meters.  All of these features were within a distance from our ship that allowed for relatively easy sampling and collection of specimens as well as field deployment of instruments.

         In 2004, our first sample site was the Bockfjord Volcanic Complex (BVC) including Sverrefjellet volcano, which rose up from sea level to over 500 meters. Vertical lava pipes, some of which are filled with unusual magnesium-iron types of carbonate minerals, are relatively rare on Earth. These rare mineral forms were cemented into lava rocks and were part of the draw to go to this remote area. Previously, Hans and Allen Treiman (Lunar Planetary Science Institute) found these rare carbonate minerals in the form of small globules on Sverrefjellet volcano (Amundsen, 1987). The globule-like mineral’s form is nearly identical in appearance to similar minerals in the martian meteorite ALH84001—the famous martian meteorite reportedly harboring extraterrestrial life. Work in 2003 hinted that there was microbial activity on the layered magnesium carbonate coatings on the BVC lava conduit walls. Our stable isotope data suggested that the coatings were deposited from low temperature glacial melt-water, and not by the action of microbes.

         Across the inlet from the BVC were the high, steep Devonian red beds that looked strikingly like the iron-rich red rocks of Mars. Although these weren’t as satisfying geologically to us, they cast a certain spell when you climbed these mountains letting you easily imagine you were walking on the surface of Mars itself. One year, postdoc researcher Jake Maule borrowed a prototype space suit and roved through the redbeds reminiscent of Armstrong’s first moonwalk in 1969.

Microbial Life in Svalbard
         It is generally presumed that if we are able to detect life on another planetary body, it will most likely be similar to our simplest forms of life--the microbes. Therefore, NASA concentrates on looking for microscopic signs of life and that is basically how we searched for “signs of life” during the 2004 AMASE trip as we sampled along the flanks and waters of Jotun Hot Springs. On the travertine terrace, several tens of meters high, the water from three spring outflows had temperatures around 30°C. At each outflow, a small pool 1 to 5 centimeters deep supported a dense covering of microbes and algae, green in color, and often filamentous. As the effluents passed down the travertine slope, they cooled and were replaced by larger filamentous organisms and diatoms. I was drawn to study the thermophiles there and the scene brought back great memories of fieldwork in Yellowstone National Park. Now working with the Carnegie and JPL groups, we developed a completely different sampling and strategy plan.
         We took a step “backwards” so to speak and walked away to refrain from immediately collecting the obvious organisms in the springs and devised a coordinated sampling plan on the terraces adjacent to the springs hoping that they would present a greater life detection challenge. The Carnegie team was determining the microbial composition and biomass using field-based PCR and an ATP-based instrument that used an extract from the horseshoe crab to find microbes. My task was to measure inorganic nitrogen compounds extracted from these samples as well as to determine the absorption spectrum of microbial pigments.
         The JPL group was testing a ultraviolet (UV)-fluorescence prototype instrument. We argued for several hours on the outcrop before taking the first sample and making measurements. The microbiology group sampled first so as to avoid contamination that could come from our activities.  I sampled next, since my sampling was simple: a scoop of rock powder adjacent to the microbiology sample. Last came the UV-fluorescence team who took their time troubleshooting their instrument along the way. They encountered numerous problems including computer screens that literally froze, telephone type cable connections that shrank in the cold and made no contact, and light contamination from sunlight. 
2004 microbe sampling crew, Jotun Springs

         Nitrogen concentrations in travertine samples were more than three times greater than volcanic rocks nearby. In water collected downstream from the springs’ sources, nitrogen concentrations indicated a type of microbial metabolism called nitrification in which the compound ammonium is converted to nitrate by specialized microbes. Pigments indicated there were traces of chlorophyll, the green pigment in plants. In many samples, light absorption in the near ultra-violet range indicated the presence of the scytonemin, a microbial pigment synthesized to protect organisms from UV damage. The absorption bands were especially strong in what we called “black” and “white” sediments taken adjacent to the springs.
         Back in the lab at the Carnegie, I analyzed total nitrogen as well as the carbon and nitrogen isotope biosignatures of the organic matter of these samples. The isotope patterns of carbon and nitrogen in biomass and rock samples from Jotun Springs varied over short distances reflecting the activity of living microbes in effluent waters. If there had been no microbial activity, I would have found uniform isotope patterns. Based on the carbon signatures of microbes, we surmised that the concentration of dissolved CO2 coming from the hot spring sources must be high. Again, if we were measuring the carbon signals of abiogenically derived organic carbon, we would expect the patterns to be much more uniform.
         On Earth, it is virtually impossible to find anything that is not slightly contaminated with organic carbon. Even pristine aluminum foil, for example, has a thin layer of oil on it from the manufacturing process. We geochemists call this ubiquitous carbon--“background” carbon. When we measure the isotope composition of this “background” carbon it is almost the same the world over and looks very similar to the carbon signature of oil.  I concluded that based on changes in nutrient concentrations over the spatial extent near the springs, elevated concentrations relative to igneous rocks,  the absorption of light by pigments, and the variable isotopic compositions, these represented biosignatures of life in these samples.
         Over the years we made many trips to the other thermal area called Troll Springs, which are located about 6 kilometers from the shoreline. The hike there circumnavigated Sverrefjellet Volcano and crossed a marshy area where we had to step on clumps of moss to prevent sinking in quicksand, before reaching a rushing, cold Arctic river about 100 meters wide. There were few comfortable or safe options for crossing the river. Option one, encase your hiking boots in trash bags and run quickly through the water, hoping the bags stayed on your boots. Option two, put the trash bags over your feet, then back in your boots. Wade more surely through the river channel, but you’ll have wet boots on the other side. Option 3, run as fast and as fleet as you can and hope that your boots remain as dry as possible. All three options generally resulted in cold feet and wet boots. Having a dry set of socks in your backpack was a good idea.
         Troll Springs spread out on the landscape for about 500 m. Some of the springs had dried completely, while others pumped out fluids at full blast. Those with active flow supported robust communities of microorganisms. In 2004, we discovered a relatively small area at Troll Springs littered with hundreds of small bird bones. Upon closer inspection, we realized the bones were clustered around an Arctic fox den, which was situated on the side of a dormant spring where the soil was warmed year round. Immediately, I collected bones and soils from around the den.
         During repeated trips to Troll Springs over the next five years, it appeared that a fox inhabited this den continuously. Based on the isotopic composition of the soils, the fox’s “influence” on the landscape through its feeding and excreting activities extended 60 meters outwards from its den. Plants growing on those soils had distinctive isotope values for both carbon and nitrogen that showed “fertilization” from the fox’s prey caught on the shorelines. Isotopic analyses of the small bones from birds showed the fox ate both terrestrial (e.g., ptarmigan) and marine birds. About 80% of the bones were from marine seabirds, such as kittiwakes. That wiley fox was responsible for bringing nutrients from the ocean into a nutrient-starved terrestrial environment creating a green “hot spot” that could be seen from some distance. Although “foxes on Mars” is a ridiculous notion in itself, this discovery was a robust example of how biological processes of organisms can physically and chemically alter the landscape in which they lived.

Phase 2: Astrobiology Science and Technology for Exploring Planets
         By the 2006 expedition, the priority for AMASE trips shifted towards testing new instruments in the field prior to their being selected for space flight on upcoming Mars missions. Each year we worked with a JPL crew that brought along a sophisticated rover that was put to the test on slopes and terrains similar to those found on Mars. JPL scientists took turns operating the Cliff-Bot rover. This team was given 2-3 days of special time to test their rover. Many of us envisioned the rover swiftly covering the landscape in a matter of minutes, reaching out its robotic arm, scooping up sediment and returning faithfully to its base. Unfortunately, sending a rover over a complex landscape, as though it were on a remote planetary body, was a much slower, hour-by-hour and inch-by-inch process that tested the patience of many a crewmember. 
The rover team at Jotun Springs

         The project now included two instruments that were ultimately chosen to fly on Mars Curiosity: CheMin and SAM (Sample Analysis on Mars). CheMin is a miniaturized instrument for determining the structure and composition of minerals in a rock or soil sample. Today, CheMin is on Mars and has been busy and successfully analyzing martian mineral samples on the Curiosity rover. CheMin’s Principle Investigator and inventor is David Blake, a scientist at NASA Ames. Blake, a US Navy veteran and an expert in designing and testing field X-ray mineralogy instruments, is also quite a character. Dave sang Navy songs laced with profanity, told jokes and funny stories of all types, and laughed with a distinct pirate-like “Har har.” To say he brought some “color” to the expeditions is an understatement.  SAM’s PI, Paul Mahaffey, brought a crew of scientists from NASA Goddard. SAM is a combination gas chromatograph-mass spectrometer (GC-MS) equipped with the capability of high temperature pyrolysis GC-MS and a tunable diode laser for measuring methane and its isotopic composition. CheMin was fully portable and field deployable; SAM was not.
         In addition to instrument teams, Steven Squyres, the PI of the Mars Exploration Rover mission with Opportunity and Spirit, was invited to observe sampling in the field and to conduct mock Mars sampling exercises (Science Operations Working Group: SOWG--pronounced “Sahg”) based on his experience “roving Mars” from Earth. Squyres was our most “famous” AMASE participant. We were a bit in awe to first meet him, but he quickly adapted to the informal, give-and-take atmosphere of discovery that was AMASE. Steve is a rail thin guy who likes to climb ice mountains in winter and must have the metabolism of a bird. Dressed in black track jacket and jeans with his head wrapped in a red printed bandana, Squyres led the SWOG sessions seriously. He also had the chance to participate in active fieldwork, where he was often a fish out of water so to speak, since he is a space and planetary scientist with little training in biology.  He particularly enjoyed helping out Verena Starke with her work and sampling at Troll Springs.
Dave Black (center) with CheMin on board ship with Fernando and Ivar

         The SWOG exercises were designed so that scientists and engineers, required to work together in teams during real missions, would learn as a group how to conduct Mars science from Earth. The question of how to access suitable samples had to be tackled separately with specialized practice with the rover team. Our second question--how to identify, sample and detect molecules of interest at suitable spatial and detection sensitivity scales?-- took up most of our time.
         For many of the last AMASE expeditions, about three SOWG exercises were held each expedition in later years. AMASE photographers took panoramic photos of rock outcrops that were sent back to the team “on Earth”--meaning inside a room on the ship--for them to analyze. Those on board ship were assigned to Mars instrument teams. Each team was assigned an energy budget. For each measurement requested, the team needed to use up one or more of its energy allotments to “pay” for the analyses. This would mimic the limited energy resources available on the Rover on Mars. Teams practiced making the best use of the energy resources available each martian day, which is called a “sol” because it is slightly longer than an Earth “day”.
         After the teams finished arguing about where on the outcrop the samples should be taken and how they would use their precious energy resources, the crew on land sampled the outcrop with hammers and delivered the samples to the instruments. When the analyses were completed, data were “downlinked” from “Mars” to “Earth” for inspection and analysis. At this point, teams argued whether they were able to detect molecules of life on “Mars.”
         These exercises were intense: periods of high drama and discussion, followed by periods of restless inactivity, cooped up on the ship or lounging on a rock outcrop. All samples were brought back to the ship and analyzed by the full AMASE crew with a summary report for each SOWG exercise. As ASTEP funding and matching European Space Agency funding neared completion in 2010, AMASE entered a period of uncertainty, in particular about its focus on discovery-based science versus technology testing. Folks like Blake and Mahaffey needed to turn their attention completely to Mars Science Laboratory, the mission to Mars that landed the rover, Curiosity. The yearly, international expeditions with Hans, ESA and NASA collaborators, and Carnegie scientists ended anticlimactically.
Polar bear eating a seal instead of us!

Insights into Teamwork and Collaboration

         AMASE began as a small, tight-knit group of scientists, artists, and PR people from around the world. Hans Amundsen had the vision to create AMASE and managed it peacefully for many years. When we received NASA funding with Steelie as Principal Investigator, the dynamic changed. Hans became Expedition Leader, and Steelie, Chief Scientist. The management team met every year in either the U.S. or Europe to plan the next year’s expedition. We loved each other. Steelie and Hans were like brothers. We developed Rules of the Road assuring that we were “One for All, and All for One.”
         Things changed when some groups had better success and followed through with abstracts to international conferences and drafts of manuscripts. A few of the scientists never shared their data for one reason or another. Whether this was fear of not getting funded or scooping one instrument team versus another is not clear. By 2009, the team had seemed to me to be falling apart. There were those people who were seasoned Arctic veterans and those that weren’t hardy Arctic explorers. I was never sure at this point in time where I lay. Money and funding, press coverage, and relationships with NASA and ESA often seemed to be more important than science and collaboration. The last AMASE in which Carnegie folks participated ended on a disappointing note. I was glad that I did not join that year.
         The strong personal bonds built in 2003 had been reduced to thin threads. Communication was strained. I felt sad to hear of the troubles between individuals and groups. This was one of my favorite endeavors of my career, some of my very favorite colleagues. We gently parted ways. Hans and Steelie entered a silent truce. NASA’s Mars Science Lab with its rover Curiosity launched and the instrument folks and engineers shifted their efforts there. Where did things go wrong?
         Hans and Steelie have strong personalities, sizeable egos, and direct visions of where they want to take their lives. Amazingly (or AMASEingly), their personalities, egos, and visions intersected for a time producing the success of AMASE. As their visions diverged, the personalities (and egos) could not sustain the collaboration. While I remain close to Steelie--often we say as science brother and sister--I am no longer in direct contact with Hans about what we discovered that still needs to be published. Nearly ten years after the last official AMASE, I recall those great moments of seeing walruses and polar bears in the wild, the thrill of fording an Arctic river, and hiking across glaciers.
         Did we accomplish what set out to do? Yes. AMASE contributed significantly to the training of scientists and engineers currently involved in active Mars science and in planning Mars 2020. Paul Mahaffey, SAM’s principal investigator, brought an international team of younger scientists with him, some of whom were very field savvy and others who had little experience picking up a sample and analyzing it. This talented group cut their analytical teeth in funky labs on the R/V Lance using a primitive prototype of SAM. The experience surely has contributed to the overwhelming success of this team with its dozens of Science and Nature papers from the “Curiosity” rover.
         Although a different rover came on AMASE, the rover engineering team from JPL had to learn what their system would do under much more challenging conditions than they had previously experienced. As observers, the rest of the AMASE group watched this team struggle and overcome personal differences in style and talent. All of them continue at JPL, driving rovers on Mars. Blake’s CheMin team sashayed into Svalbard with a strong prototype and a coordinated team. They left with a stronger idea as to how their instrument could integrate with the search for life. Their work remains a cornerstone of Curiosity.
         Students were trained and postdocs tested. They learned to trust themselves in a remote, hostile environment and to get along on the tight quarters of a research vessel. I think it’s fair to say that they will never go on a better field expedition than AMASE in their lifetime—unless they make the trip to Mars. Further, they rubbed shoulders with the movers and shakers of astrobiology, exchanging ideas, working out problems. There is no better way to engage and retrain young scientists than a voyage like this.

Rounding Third Base and Heading Home

Cards from Franny and Flowers the Rumbles   My daughter Dana is marrying George Goryan on June 25 at our home in Mariposa...