Agathe Toumoulin, PhD, Paleoclimatoecologist

Me, animating a climate modeling workshop with middle school students for a Science day in the lab (CEREGE, Aix-en-Provence, France).

How did you get interested in science in general? To some degree, my family probably played a role by cultivating my curiosity. My dad, by making some electricity home experiments from time to time (I think his favorite, and more impressive to us was: putting a light on from a potato!), my mom by loving plants and growing flowers everywhere, my aunts by occasionally brining my sister and I to zoos and museums. However, I don’t think any of my family and friends would have predict I would work in the science field. Until my 20’s I was more on the road to become stage director, art or theater critic, or even visual artist. After studying theater, languages, philosophy and literature in high school, I decided to start medical studies with the motivation to learn about the human machine functioning. After a few months, I realized it was hard but not exciting at all. Therefore, I decided to move to another discipline and while I was hesitating between art history and biology, I choose the second option. And this was the good one. I will always remember how my BSc botany and zoology classes were captivating. It was like learning about so many aspects of our world I never questioned before: what muscles make an earthworm move? How does a clam breath? What processes enable plants to move? How many lichens are there on the trees around? Without mentioning field trip on country side identifying plants and fungi, or on an island, collecting algae for herbarium… All these experiences really change the way you apprehend your environment! A tipping point in my formation was my first research internship in paleontology, during this experience I measured a hundred of belemnites (an extinct group of marine cephalopods) but more importantly, I realized I wanted to become a researcher. Of course, I feel really lucky that our public education system is (for the moment) not expensive, as compared to most other countries’. This enabled me to test for different branches and find my own. 

Late Eocene Eotrigonobalanus furcinervis fossil leaf (Museum für Mineralogie und Geologie, Dresden, Germany).

In laymen’s terms, what do you do? My work aims at reconstructing deep-time (i.e., millions of years old) environment and climate characteristics using fossil plants (wood and leaves) and Earth System Models. 

An Earth System Model is a numerical tool that calculates the earth’s climate according to a number of parameters. It is often used to predict how the climate will be in the future. It allows us, for example, to estimate how much the earth should warm up for a given increase in greenhouse gases concentration in the atmosphere. For the past, climate models allow us to assess the effects on paleoclimates of big changes, often suggested by fossils, such as changes in continent position, relief, volcanic activity, sea-level, or greenhouse gases concentration.

Fossil plants enable the reconstruction of past local to regional environment conditions. We can use fossil plants in different ways: (1) by identifying them and looking for their current closest cousins (called nearest living relatives). As we know in what conditions these live, we can then hypothesize the related fossil species had close preferences (in terms of temperature, need for water, nutrients); (2) – this is what I prefer by far – by looking at the size and shape (called physiognomy) of the fossil leaves. We know, thanks to numerous measurements of global modern vegetation, that leaf size and shape change according to the conditions in which the plant develops. For example, leaf size changes with the amount of rainfall: leaves are larger in wet areas, where plants are not likely to dry out. 

Examples of results from different climate simulations made with the French Earth System Model (IPSL-CM5A2). Hundreds of parameters can be analyzed! Our experiments use a middle Eocene paleogeography, which explains some differences in continent location!

Here is an example of my work to better illustrate the use of these tools. My MSc internship and PhD were focused on the Eocene climate (between ~56 and 34 Myr ago). We know from several indicators, notably because fossil plants close to extant tropical vegetation and crocodilian bones were found at very high latitudes, near the Arctic Ocean, that this period was globally warmer. Despite on average higher temperatures, this period is particularly known for a long-term climate cooling, responsible for the Antarctic ice-sheet growth! By studying the evolution of leaf shape of a fossil beech leaf assemblage, I tried to see if this cooling was visible in Germany. Then, using climate models, I tried to understand which parameters were responsible for this change. In the different modelling experiments, we tried to understand how the major changes described at that time: changes in paleogeography (more precisely, the Drake Passage opening), drop atmospheric concentration in CO2, Antarctic ice-sheet expansion, and the associated drop in sea level (the growth of continental ice-sheet result in sea-level lowering), may have affected the Eocene climate and if some of these parameters could explain the global cooling!

How does your research/goals/outreach contribute to the understanding of climate change, evolution, paleontology, or to the betterment of society in general? My research aim at better reconstructing the evolution of Earth climate and environment through life history, but we always learn from knowing our past. Eocene temperatures correspond to those predicted for 2300 following the worst climate change scenario (RCP8.5). Studying this period of time may provide some information on the manner a globally warmer climate works. It also constitute the opportunity to test the validity of climate model predictions for the future: paleoclimate modeled can be compared to climate estimates obtained from proxy-data. However, Eocene and modern world aren’t fully comparable, there are important differences, notably in the continent location (ex. North and South America were not connected during the Eocene). This means that we cannot necessarily apply our knowledge of the Eocene to the future. For my part, I find that my research is important for its historical significance, to understand how global biodiversity got here. 

Jurassic coniferous fossil wood from Antarctica, University of Kansas, Paleobotany Collection

What methods do you use to engage your community/audiences? What have you found to be the best way to communicate science?  During my BSc I get a half time job, as a guide at the Museum of Natural History of Toulouse. It was a great experience that really made me want to connect people to science. Since then, I designed and animated some workshops around biodiversity and climate for children. I am not a professional in Sci Comm, but for me, communicating science starts by establishing an equal relationship between researchers and the general public. We all know things. I like to instill confidence in people, by making them participate, and then share original anecdotes on a given topic. These anecdotes are not necessary complex mechanisms, nor the most recent scientific discoveries, but stimulate curiosity and raise interest, and I think it’s the first step for people to get into science. 

Me, looking for Permian fossil plants in the Lodève Basin (France) during a field trip organized by the association Agora Paleobotanica.

What is your favorite part about being a scientist ? There are different aspect of working in science I really like: 

To marvel and play – To me being a scientist in paleo- is like a game, there are some clues around (and not always your favorite) and you must get some information from that to picture how the environment was millions of years ago. For now, I’ve been working on 35 to 180 Myr old periods which differs through many aspects of our everyday life context. To me working on these ancient landscapes is somehow like traveling (I guess that fiction authors may also feel this way). 

Being part of something bigger – Although, we sometime feel like being in a very specific research niche, there are at least dozens of people working on similar/complementary questions around: you are part of one community! This network structure really opens up research questions that can be addressed. I like contacting people from other country asking for their expertise and exchange.  

Being free – One of the big advantages of research is also that you are relatively free in the work you do and the way you do it. It certainly depends on the labs and teams you’re part of, but in general you manage your time and projects, being your own boss in a way and this is something I really like. I’m currently writing my first postdoctoral research project and I really feel like I can build something that fits me 100%.

What advice do you have for aspiring scientists?

  • Do as many internships as you can: these experiences will help you define your interests and what you want to do, and meet inspiring people.   
  • Do not hesitate to contact / talk to people! Although everybody is busy, people generally like you being interested in their work and may provide you help (e.g. on special methods) or advice (including for your career!). 
  • Do not censor / limit yourself: just because you never worked in a given field/with some methods doesn’t mean you won’t be able to succeed. Believe in yourself and work hard enough to explore research areas that interest you.

Follow Agathe’s updates on her website and Twitter!

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