|Woods Hole Isotope Camp, 1986: Brian Fry, Marilyn, Bob Michener front row center|
2nd row: Marion O'Leary (center) next to Chuck Douthitt, then Ron Benner (2nd from right)
3rd Row: Kate Lajtha, Terry Chapin (left), Tom Jordan, Brad Tebo (right)
When you’re a kid, if you’re lucky, your parents might send you to camp in the summer to learn new skills or just have fun. My children attended nature camps, art camp, horseback riding camp, and sports camps, as well as a “just be silly and have fun” camp. My childhood friend Franny Stein (Kasen) excelled at doing camp first as a camper, then a counselor in training, and eventually a counselor. She held court every summer at overnight camps that lasted months. The friends she met there sustained her throughout the rest of the year. And in fact, she met her husband at camp when she was a lifeguard at the Jewish Community Center day camp in South Jersey. Good things can and do happen at camp. Similarly, students interested in the field of stable isotope biogeochemistry meet peers and network at what is becoming very popular—isotope training camps.
To learn the “Ins and Outs” of stable isotopes these days, graduate students and postdoctoral scholars often attend Isocamps—week(s)-long training sessions with lectures by experts (Isopopes) and laboratories led by the technically savvy (Isocopes). The first workshop that I organized for students to learn about stable isotopes was in 1982 on the more general topic of “Biogeochemistry.” Sponsored by the American Geophysical Union (AGU), about 25 young scientists came to the Geophysical Laboratory for 2 days of lectures from microbiologist Ken Nealson, organic geochemists John Zumberge and Bernie Simoneit, my Geophysical Lab colleagues Tom Hoering, Ed Hare, Steve Macko, Michael Engel, and me. We were educating a new group of people who wanted to think outside of their disciplinary boxes. Some of the students who attended that workshop went on to become leaders in biogeochemistry. We didn’t include a laboratory component, but I learned how to bring senior scientists on board, show enthusiasm to people outside my field, and develop lecture skills.
I learned enough from this experience to do a much better job for the isotope “camp” I organized in 1986 with my colleague Brian Fry, then a scientist at Woods Hole Marine Biology Lab in Massachusetts. Brian Fry and I had worked together as graduate students at the University of Texas Marine Science Lab in Port Aransas. Essentially, we’d “grown up” together going from being “Isodopes”, learning our way to becoming young “Isopopes”. We planned our workshop with lectures in the mornings and evenings with laboratories in the afternoons. For the lectures, we brought in some big names at the time—John Hayes, Marion O’Leary, and Leo Sternberg. Each of us had a full day to give our lectures that concentrated on the basics in the morning followed by more specific examples in the evening.
Brian and I worked with his lab manager Bob Michener to set up six glass vacuum lines for processing samples for isotope analysis. This was a feat that required much planning and thought. Each vacuum line needed its own vacuum pump, metal support frame, liquid nitrogen flasks, clamps, and sample bulbs. Fortunately, we were able to make a simple design that worked well and purchased six lines from a local glassblower. Our students worked three to a vacuum line so that they became intimately familiar with how they worked.
|Isotope camp students and lecturers, Patagonia, 2013|
Each group of students designed a simple research project on Monday, collected samples, prepared them, and analyzed them by Thursday. They presented their results on Friday. Bob needed to make sure all the fragile vacuum lines held a vacuum and didn’t break. He also needed to make sure the isotope ratio mass spectrometer was in tip-top condition so he could finish all the analyses by Thursday night. Nothing was automated at that time, so each and every sample required hands on careful attention to details.
The class was a raging success!! It was a great sense of accomplishment for me to carry this off, including showcasing my abilities to important Isopopes like John Hayes, a decided leader of stable isotope biogeochemistry. Brian, Bob Michener, and I really enjoyed working together. Even today, I believe the shared experience from holding this workshop almost 35 years ago remains a fond memory for the three of us. Many of the students from this class went on to use stable isotopes to solve scientific problems in their specific disciplines.
|Brian Fry's cartoon on isotopes-masterpiece!|
Brian Fry used this experience to write the first textbook on Stable Isotope Ecology, a somewhat folksy rendition of an otherwise serious subject. I’ve used parts of this book for teaching Isocamps and full on classes during my career. Brian made up cartoons of people with their hands, body, head, and feet as stable isotopes. He drew an illustration of “light” and “heavy” isotopes paddling a canoe with the heavy isotope’s figure tilting the canoe dangerously. Brian’s cartoons of isotopes are classics in our field of isotope scientists and convey to even the most chemically-adverse student the basic rules of stable isotope chemistry and physics.
|From Brian Fry's book, Stable Isotope Ecology|
Chemistry and physics—two subjects that strike fear and loathing in the hearts of many who eschewed science and studied the liberal arts. In fact, even science majors have a certain dread about taking organic chemistry classes. To get a deeper understanding of the stories in Brian’s book, bear with me and consider a couple basic rules first articulated by Marion O’Leary, a physical chemist who was very influential in the 1970s and 1980s.
Recall—atoms are made up of protons (P), neutrons (N), and electrons.
Rule #1: Lighter isotopes go through chemical reactions faster than heavier ones.
This makes sense to just about everyone. For example, thinner, lighter people typically can run up hills faster than thicker, heavier people like me.
The lighter isotopes that have one or two less neutrons like 12C (carbon atoms with 6P:6N), 14N (nitrogen atoms with 7P:7N), 16O (oxygen atoms with 8P:8N), and 1H (hydrogen atoms with just 1P), form chemical bonds easier and faster than the heavier isotopes: 13C (6P:7N), 15N (7P; 8P), 18O (8P; 10N), and 2H (1P;1N) that have an extra neutron or two.
Rule #2: Heavier isotopes form stronger chemical bonds than lighter ones.
This concept is harder to grasp, but let’s work through it. Chemical bonds hold together important molecules like sugars in which hydrogen and oxygen atoms are bound to carbon atoms.
The heavier isotopes stick to other atoms more strongly. While the lighter isotopes will form chemical bonds more easily according to Rule #1, they also break apart more quickly later on. The heavier isotopes need more energy to form a bond initially and they require more energy later to break these bonds.
Rule #3: Beware of over interpreting small isotope differences or patterns.
Although we can break the chemistry and physics down into a couple of simple rules, the natural world is much more complicated than that! A living organism carries out thousands of biochemical reactions every second. Comprehending the shuffling of stable isotopes at that scale is impossible! We rely on knowing which reactions are the most important and understanding those in greater detail. Even geological reactions, which can take place over millions of years and at extreme temperatures, take some time to understand fully.
Rule #4: You are what you eat—plus or minus a little bit.
The isotopes we eat—yes, we eat them folks—are in our food and end up in our tissues. You shouldn’t be surprised.
When we analyze animal tissues we do this to figure out what animals have been eating when no one is watching. Imagine trying to determine what a whale is eating as it cruises 100 meters below the surface of the ocean. Our work measuring stable isotopes in Australia on extinct species allowed us to figure out what animals now long gone ate! This approach enabled us to understand prehistoric ecosystems.
|Baja Mexico--Isotope camp 2012|
After a week of in-depth isotope camp, we expect students to fully grasp Rules #1 and #2, to see the utility of Rule #4 and to come to appreciate Rule #3.
Every year Isocamps are held in Salt Lake City, New Mexico, Michigan, Germany, Italy, and Chile or somewhere else in the world. Jim Ehleringer and Thure Cerling at the University of Utah held one of the most popular and longest running Isocamps for over twenty years. They branded the name “IsoCamp”, attracted a worldwide student population, and provided lecturers from around the globe the opportunity to spread their knowledge to a diverse audience.
I worked with my colleague Seth Newsome holding isotope ecology short courses in Argentina (2009 and 2013) and Baja Mexico (2012). When we held our first isotope camp in Argentina in 2009, there was only one isotope mass spectrometer in the entire country. Because there was no available mass spectrometer for us to use, we trained students in how to design ecosystem level isotope studies and how to formulate laboratory experiments to understand more complex species level isotope questions. When serious isotope ecologists like me look at a landscape, we see isotope patterns in the plants, the soil, and in the tissues of animals. It’s a talent akin to how a naturalist might examine an ecosystem identifying plant communities, stream flow, tallying species diversity, and listening for the sounds of birds and insects. It takes years to get good at imagining and speculating about the isotope patterns in an ecosystem, but with many of my postdocs, Seth and Matt Wooller for example, we have “mass spectrometer” eyes that assess a plant’s photosynthesis pathways, the influence of climate and water availability, water sources, and potential prey items.
|Luciana, Marilyn, and Seth, 2009|
In 2009, Seth and I flew to Argentina to work with Argentinian grad student Luciana Ricciardelli on presenting our first Isocamp. Earlier she had visited the Geophysical Lab to analyze samples of dolphins and porpoises found stranded on the coast of southern Patagonia. Seth and I landed in Buenos Aires with duffle bags filled with sample gear and technical books. After a short stay in Buenos Aires, we drove south along the La Plata River with Luciana to the city La Plata where we conducted our short course at the University de la Plata, a sizeable university of more than 30,000 students.
In general, Argentinians of a certain age aren’t fans of Americans. During their Dirty War in the mid 1970s to early 1980s, the CIA tacitly ignored what was happening in Argentina. In the US, we rarely learn the history of countries outside of Europe, so I was almost completely ignorant of what happened at that time. I became educated by staring in shock at the photos of “missing” students, who would have been my age (18-22) at that time. It’s now well known that dissident students were rounded up by the fascist government, murdered, then dumped off shore. It was a horrible time for Argentina. Seth and I worked hard to engender good relationships, and I think it worked.
|Seth giving informal lecture, 2009|
On the first day of the camp thirty eager students arrived. My Spanish is rudimentary to non-existent. Fortunately most students knew some English so that lectures could be conducted in English as were our question and answer periods. Argentinians drink coffee in the evening, but prefer yerba matte, a hot drink with lots of caffeine, throughout the day. Matte bowls were passed around the room during the long lecture periods. Students used a shared special metal straw to take a hit off the strong brew. In the evenings, we went out for pizza, steaks, and ice cream often meeting up with a few students in the class.
Seth and I worked nearly round the clock preparing lectures, lab practicums, and interacting with students who were thirsting for knowledge. By the time it was over we invited several of the most promising students to come to the United States as interns, and we were able to provide modest support for them.
|Students working on sample strategies, 2009|
This year, Seth and his colleagues at University of New Mexico will take over the next phase of IsoCamp as Jim and Thure have passed the torch. There are 60 applicants to fill 25-30 available slots. Clearly we had created a unique and powerful way of educating the next generation of stable isotope scientists. Working on these camps was one of the most satisfying educational opportunities of my career and a strong testament to the power of using isotopes as important tool in scientific research.
For this year’s IsoCamp in Albuquerque, New Mexico, I have been asked to give an evening lecture on a topic of my choice, not the nuts and bolts lectures that others will cover. I’ve got plenty of stories to tell—many of them good, all of them educational.
People want to learn about stable isotopes! I hope that this memoir reaches an even greater audience and when you hear the word “isotope” you’ll think of all the cool things about them.
|Marilyn (foreground) teaching isotopes, 2013|