WHO? Devapriya Chattopadhyay, 36
WHERE? Indian Institutes of Science Education and Research, Kolkata
Reported by Nandita Jayaraj
During the Cenozoic Era 65 million years ago, our planet began looking similar to what it’s like today. Dinosaurs had just gone extinct and the continents had separated. In another ten or so million years, the Indian subcontinent would collide with Asia, giving birth to the Himalayas. What was it really like in these times?
For a couple of weeks every year, a team of palaeobiologists led by the highly-trained Devapriya Chattopadhyay braves through the remote Kutch region looking for answers one fossil at a time. “Using fossil records, we want to recreate the biosphere – the surface and atmosphere of the earth occupied by living organisms, that existed before,” she said during an interview at IISER Kolkata.
It starts with a question
The job of a palaeobiologist starts with the framing a question. Of course, it is not possible for them to go right ahead and design a study to answer big questions like “what was it like 65 million years ago?” Instead, they ask one small question at a time. For example – what predatory behaviours existed between species back then? “This is a simple question to ask,” said Devapriya.
Molluscs, the group of animals that Devapriya studies, comprise over 1 lakh species of large invertebrates like snails and mussels. Many of them have shells that are studied because they are preserved over the years, making them useful archives of palaeoclimate. “Fossils of clams (a type of mollusc) are very common. They are often attacked by snails which drill holes on the clam shells. This hole is a record of predation because it gets preserved even in the fossil.”
Devapriya has an aquarium facility where she breeds the living representatives of the fossils she studies. This allows her to control the environment and get direct evidence of how these species change. While studying predation, she can experiment with clams and snails in her facility to get an accurate sense of how the size of the drill hole can be measured to identify the predator.
She can also go a step further to investigate whether the predators choose their prey randomly or specifically. For this, she creates a mathematical cost-benefit model. “The predator invests metabolic energy by drilling and also spends time being exposed to other predators while doing this. These are its costs. In return, if successful, the predator gets some soft food material that it can again convert to energy. Essentially, we make an equation with which we can evaluate how the ratio of cost to benefit changes over time. Is it constant, getting higher or lower? That will finally give you some idea of whether this predator-prey system is evolving through time or not.” Among other things, Devapriya is specifically interested in finding triggers that led to the evolution of life.
Down and dirty with the past
She requires large repositories of fossils that come from different times in the Cenozoic era. Most of her samples are collected from the Kutch region in Gujarat – a well-known location for Cenozoic rocks that is relatively undisturbed. ‘Formation maps’ prepared collectively by geologists guide her on her field trip to the past. These rough maps depict where the exposed rocks are located and what areas correspond to which age.
To practically use such a map Devapriya first superimposes it on a satellite map. Only then can her research team narrow down to localities they can target – if the rocks lie in the middle of a village, they may have to leave that spot out. Preparing for a field trip takes a month or two; over seven years into her research, this process is well streamlined by now for Devapriya. “We start with around hundred such spots. We plan to visit each of them. Maybe we can find twenty to be fossiliferous. Once we get to such spots, we start collecting fossils.”
“The process of extracting fossils is still very primitive. We are on the ground with a chisel and a hammer – there is no other way. We spend anywhere between fifteen and twenty days in the field and each year we collect fifteen to twenty kilos of fossils.” Every time a fossil is encountered, several photographs are taken. “On our return, we compile these photos and analyse each fossil’s shape – this is called morphometric analysis. All this data is digitised so that we can extract information and do statistical analysis.”
Regarding dating her samples, Devapriya informed me that it is very difficult to determine the absolute age of such ancient samples. However, for the kinds of questions palaeobiologists are typically interested in, relative dating is adequate. “We want to check only if the fossils are changing through time, not exactly how much time it took between stages. As long as we can date our samples from oldest to youngest, this sequence is good enough for our work at this point in time.”
The species are identified and finally, armed with all this information, the team is prepared to answer the question framed at the beginning of the study. Currently, Devapriya’s studies are tracking climatic variation during the Cenozoic period and documenting the response of molluscs to any fluctuation.
Studying Climate Change with fossils
Palaeobiological studies can also help us understand climate change we face today. For example – the tropics, where India is situated, were perceived to be less affected by climate variation as it is closer to the equator. However, concluding from her scientific investigations with fossils, Devapriya has reported that tropical species are not so invincible after all.
“We found from past records that even periods of slight warming in the tropics changed the biodiversity community structure significantly. Species which were dominant before took a backseat and other species became dominant in the community. Within a species too, individuals are shrinking in size,” she said. This matches recent studies of climate change, where similar patterns of size shrinkage have been documented. “We should become aware that the stability of the tropics as an ecosystem might not be as much as we think,” she emphasised.
Drawing such parallels between past and present records is crucial to get a complete picture of climate change, according to Devapriya. We can’t afford to rely on recent times alone because we don’t have enough [climate] information beyond hundred to two hundred years. “These phenomena take time – and the system is not really a linear system, meaning you can’t say there was an x effect over 100 years so you will get 2x effect after 200 years. So in order to get a perspective of a real, natural climate system, I think it’s essential to look at records from further in the past.”
A love for earth and science
Having grown up in the northern regions of West Bengal near Darjeeling, Devapriya spent her early days close to nature. “I had a very non-typical childhood compared to a city-dweller. I spent my free time with trees. My father was an amateur painter (as well as a college lecturer) and I used to accompany him when he went into the forest to paint landscapes. That was my favourite pastime. I liked observing nature, predicting what would happen next…”
Sometime during her eighth grade, she did her first piece of research for a school project on the formation of coal, petroleum and natural gas. “I really liked that experience and when I finished 12th, I declared at home that I was going to study geology.” Despite being an unusual choice, her parents gave their assent. Devapriya went on to do her B.Sc in Kolkata’s Jadavpur University and MSc in IIT Bombay. While in IIT, she went to Kutch for the first time for a geology project. “Working on my own there, the independence and the sheer joy of finding new things and making sense out of it – that changed everything… I was all set. I knew this is something I want to do for the rest of my life.”
She went on to do her PhD at University of Michigan, where she conducted most of her research at the university’s Museum of Natural History. After a brief stint in the oil industry, she landed a position at the University of West Georgia. A year later, the homeland beckoned in the form of an offer from IISER Kolkata.
India and palaeobiology
Studying India makes a lot of sense for palaeobiologists like Devapriya because the Indian subcontinent traveled a long way from Antarctica (polar climate) to its current position (tropical climate). “So there are many questions that can only be answered with Indian fossils.”
Moreover, IISER was new at the time and Devapriya was eager to bring back all her experience and start something new in India. She was especially enthusiastic about strengthening the quantitative aspects of palaeobiology in the country. “Much of the curriculum in India is very qualitative. But quantification and statistics are the tools of modern palaeobiology. It’s not just memorising – it’s actually a very interesting field where you can test hypotheses.”
Working on my own there, the independence and the sheer joy of finding new things and making sense out of it – that changed everything… I was all set. I knew this is something I want to do for the rest of my life.
On this front, Devapriya considers herself fairly successful over the seven years she has spent at IISER Kolkata. Her first PhD student was due to finish very soon at the time of this interview, and she has trained several more (MSc, post-doctoral students) who have become fairly established in the field.
There is another side to the story of why Devapriya was eager to come back to India – something she calls her ‘long-term plan’. “One issue in Indian science, especially palaeobiology, is that we have no research museums. Research museums in the US and Europe have everything that has been collected for last two hundred years and it’s all curated properly. Palaeobiologists don’t go to the field – even I didn’t during my PhD at the Ruthven Museum – since they can just work on those in the museum,” she said.
In pursuit of a museum culture
The problem with India lacking natural history museums with palaeontological specimens is that the personal collections belonging to scientists end up lost after they retire. Devapriya elaborated: “In so many universities, these collections are just thrown away. When you destroy these specimens, you are removing a part of history which we will never find again – it won’t be on the field the next time I go. That’s a huge loss for Indian heritage and science. We will never be able to compete with the rest of the world or work at the same level until we have a museum.”
So what is taking India so long? Looking irritated, Devapriya replied that she has no answer. “It really puzzles me.” When she joined IISER, she actually got the wheels rolling on this pet project of hers. “The idea to build a small-scale museum in this institute was okayed at a very hypothetical level. I worked on it, made maps and designs. Even these initial designs were okayed.” However, the delays began with a change in administration. The museum plan was de-prioritised and there has been no progress since.
We really need a national level decision to have museums. It’s a very very long-term plan, but it’s something I really hope for.
Devapriya tried to approach the national funding agencies; however, based on unofficial communication she felt that they are more inclined to hand over such responsibility to someone very senior. “I don’t qualify,” she sighed. This, despite her five years experience as a museum assistant during her PhD and her long-standing collaboration with the museum at University of Vienna. Not one to stay bitter, Devapriya still has hope. She stressed that such an effort cannot come from one institute alone, but has to come from the whole nation. “We really need a national level decision to have museums. It’s a very very long-term plan, but it’s something I really hope for.”
Gender on the field
Despite the physical aspect of palaeobiology, Devapriya rubbishes the idea that any of this is too strenuous for women to do. The only times she is made aware of her gender is when she travels alone for research. “Some places I go have no hotels – I stay in dharamshalas (rest houses). The people there sometimes ask me if I’m alone. That makes me uncomfortable because I know the next reaction will either be to deny me a room because they cannot ‘take responsibility for me’, or to become very overprotective – I absolutely hate this. All I am asking is for them to act professionally. I want to be able to get a place to stay when I pay for it. Instead, I get asked questions like how do you do this, what does your family/husband say – I consider this an invasion of my privacy. My male colleagues don’t face this.”
Devapriya is married and has a daughter who goes to IISER Kolkata’s creche while she is at work. “Without the creche, I could not have survived and led this active life. This year, when I went to the field, she was primarily with her father and her grannies. But you know, it’s not so simple. Motherhood changes you and you need passion to come back to your old self without neglecting responsibilities.”
A fright in the Kutch
“Once, my students and I were staying in a guesthouse at Narayan Sarovar, a place at the westernmost part of India in Gujarat. It was really remote; an army base was 1km away and the nearest village was 10 km away. It’s pretty much in the middle of nowhere. We were in a big group – the boys were in one room and the girls (and me) in the other. In the middle of the night, there was a loud knock on our door. Three strange men came into our room and said something in Kutchi which I could not understand very well. They roamed around the room like they were searching for something. We were frozen. All I could think about was the safety of my students. After they left, we went to the hotel staff and I shouted at him. They told me that they were helpless as the men were from the local Panchayat and were looking for a couple who had eloped. I wondered what the fate of that couple would be. I can only imagine… The next day we lodged a complaint and this was taken up by Gujarat Tourism. This was the brighter side because even after this incident we had no luxury to avoid this guesthouse. There is no other place around to stay.”
Was this not a deterrence for you and your students? Devapriya smiled.
“You see it’s like this – say, you are working with heavy machinery and there was a fire incident. Would you stop working? No, you would just be careful next time. That’s what we do…”