Episode 1: Sonal Khanolkar, The Foram Time Traveller!

Sonal Khanolkar, Ph.D.

Sonal has keen interests in understanding the life strategies of shallow marine foraminifera during the extreme climatic perturbations in the Paleogene using trace element geochemistry. After complete of her post-doc in Germany, she wishes to join as a permanent faculty in a premier institute within India and start her own research group. She is also a strong advocate of women’s rights, diversity, and inclusion.

Using the RSS feed link to subscribe to your favourite podcast app is a work in progress and currently is available on Spotify and Apple Podcasts. We will keep you updated on availability to other sites. Below is the full transcript of the episode. Enjoy, and please do provide feedback or get in touch with Sonal Khanolkar via Email: sonal.k.12[at]gmail.com or Twitter: @Sonal_Khanolkar


Jazmin, Nuzhat, Sonal

Jazmin: 00:07

Hello, and welcome to the What On Earth Podcast. I’m your host Jazmin.

Nuzhat: 00:11

And I’m your host Nuzhat. In this podcast we celebrate Earth, environmental and planetary scientists from diverse backgrounds and get to know what they’re up to.

Jazmin: 00:23

And we also speak to scientists from different disciplines about how we can decolonise science to make it more inclusive for everyone.

Nuzhat: 00:31

This episode, we will be interviewing an earth scientist on their research.  Today we have Sonal Khanolkar. Hi, Sonal.

Sonal: 00:39


Jazmin: 00:40


Nuzhat: 00:41

Could you introduce yourself to our audience?

Sonal: 00:44

First of all, thank you for inviting me to speak. And both of you are doing a fabulous job. Well, I am Sonal Khanolkar. I was working all these years in India. And I did my bachelor’s, master’s and PhD from India. I worked in geology. And then I did my PhD in micropaleontology. I was a DST inspire faculty in Indian Institute of Technology Kanpur, where I got to work for two years. And then I lead my own independent project. And then I was selected by MPI, Max Planck Institute of core chemistry for doing a postdoc. And I am here right now since the past year, and I’m really enjoying myself. So I work basically on microfossils called foraminifera and try [to] understand the past climates using their chemistry.

Jazmin: 01:50

Ah, that’s amazing. But what, what made you want to become an earth scientist and particularly study paleontology?

Sonal: 01:59

Well, when I was in my high school, I used to watch a lot of programs on National Geographic Channel. And one of the programs featured the Mars exploration rovers, Spirit and Opportunity, which were launched by NASA at that time. And these rovers are particularly launched to study the surface and geology of Mars. This made me very curious about the field of geology. And I started reading a lot more about it. And then I was particularly fascinated by the extinction of dinosaurs, which happened around 65 million years back by the meteorite impact. And all these things led me to pursue a career in earth sciences as I was really fascinated by.

Nuzhat: 02:58

So, you did an undergraduate degree in geology in India?

Sonal: 03:02

Yes, I did it from Saint Xavier’s College in Bombay. And it was, it was a really good experience as I was in geology for the first time. So.

Nuzhat: 03:15

So, this might be a cliché question, because I’m also half Indian. How did your parents react when you said you wanted to study geology?

Sonal: 03:26

Oh, in India? Well, there is a craze for engineers, and doctors. So basically, all parents want their children to grow up and pursue these careers, instead of doing basic sciences or all sciences was rarely, rarely something that they didn’t think of at all. And when I first went and told them, I want to do geology, they thought that I was not serious about my academic career.

Nuzhat: 04:01

I guess I could completely empathise with that. I had to convince my parents that this is what I wanted to do. Were they happy, too? Happy to let you pursue this? Or did you have some kind of debate with them? Did you have to try and convince them?

Sonal: 04:18

Yeah, I had to convince them quite a lot. And but then once I started doing, I joined Saint Xavier’s and I did fairly well in my academics. I think they were pretty happy that, “okay, now she’s probably serious about her career, and I think she will do well”, then they were very supportive. And today, they have been extremely supportive of what I do.

Nuzhat: 04:43

That’s really good to hear and have plenty of reasons to be proud of you. Yeah.

Jazmin: 04:50

Yes. So, in that case, good that your parents are having you doing this now. But why pacifically did you choose to pursue micropaleontology.

Sonal: 05:03

So, well after my bachelor’s from Saint Xavier’s, I joined the Indian Institute of Technology in Bombay. And my guide, Professor Pratul Kumar Saraswati, was the teacher who taught us the paleontological course in master’s. And he introduced us also to micropaleontology. And I thoroughly enjoyed learning about microfossils, and particularly about foraminifera and how that these tiny little micro-organisms can not only tell about the geological age, but about also how the climate was by studying the chemistry of their shells. So, I was particularly fascinated by this topic. So, I thought I should do my PhD in it.

Nuzhat: 05:56

Can you tell us a little bit about your PhD and your postdoc?

Sonal: 06:00

Yeah, so I work on these microfossils, as we know now called foraminifera, they are informally called as forams. And they are single celled tiny organisms, with shells which are made of calcium carbonate, mostly. And they are as they are tiny, they but they are not as tiny they are, they can. I mean, they can be from sizes of 50 microns to as huge as five centimeters. So, what I do is what I did in my PhD is that I studied a particular time period called as the Paleogene, which spans about 23 to 66 million years. And what was the interesting part about Paleogene is that the earlier part of Paleogene, around 55 million years ago, there was a more sudden rise in the temperatures of the Earth, and there was an increase in the CO2 to about 2000 ppm, which is four times of what it is today. Yeah, yeah, it was, it was a lot of CO2 that time and, and I wanted to know, how did the micro-organisms react to that kind of high temperatures. Because if we continue the kind of carbon emissions that we are doing today, it will I think there will be hopefully not but that is the climate state that we need. And we want to project that, how come the biota reacted [to] that kind of warming. So, it was pretty interesting a topic for me. And it was also during this Paleogene, that the climate states changed. And around 30-35 million years back, there was the formation of the first ice sheets in the Antarctic. And it is interesting that how climate sort of cooled down, and then the ice sheets also developed during the same Paleogene period. So, I wanted to know the assemblage of these tiny microfossils and how they reacted to different climate states. And that is the same thing that I’m doing in postdoc.

Nuzhat: 08:33

I had, I had like, two questions. One was, when you told us about there was a change in the climate, do you know what caused the change?

Sonal: 08:45

Yeah, actually, it was a very, so we can hypothesise many things. And one of the famous hypotheses is that that there was a development of the Antarctic Circumpolar Current around the late Eocene, early Oligocene. And that gave rise to the formation of ice sheets in the Antarctic. [Nuzhat] Okay. [Sonal] Yeah.

Nuzhat: 09:12

And secondly, so when you say these forams, is there a particular locality that you’re looking at?

Sonal: 09:20

Me, I study the forams from the sections in India. So, it is in the West, most of the field, we do a lot of fieldwork. So, we go to the western part, of the northwestern part of the country, which is in the Gujarat State, and there are a lot of microfossils there and of the Paleogene age. And yeah, and they’re very well preserved. So yeah, it’s a nice study area.

Nuzhat: 09:56

And so, what was fieldwork like? Did you enjoy fieldwork?

Sonal: 10:00

Oh, yes, I love for you to work in, in Gujarat. I mean, it’s a very nice State as well. And it’s, I really enjoyed it, because what you don’t get to- I mean, what for geologists, the fieldwork is the most important and exciting part of their work. Because that is where you go and actually collect samples and geology is in observational science. So, you could want to go there and observe the fossils, how the deposition to sedimentology is. Yeah, so it is a very important part of your PhD or postdoc work as well. It was great experience.

Nuzhat: 10:46

Okay, um, yeah, I was, I never enjoyed fieldwork when I was doing it during my undergraduate. But when I started, kind of when I was traveling, and I was trying to look up for the geology, I enjoyed it a lot more when I was doing it at my own time. So, it’s got like, fieldwork, sometimes even if you don’t enjoy the beginning, when you’re doing it for your own self, or your own research is a lot more enjoyable.

Sonal: 11:10

Yeah, I know, I can. Yeah, because in your undergraduate or postgraduate, you are taught something. And so you have to go to a particular section, because the teacher tells you, but in your PhD, you can explore things on your own, and you have your own time, and things in different manners.

Nuzhat: 11:30

So, what did you do during a PhD? And what are you doing that’s different for your postdoc?

Sonal: 11:36

So in my PhD, I did more on the, I work more on the examining the taxonomy of the different species, and trying to understand the age models trying to perfect the age models, because it’s important to do field work not just because you are collecting samples, but because you want to know what age of the sediments basically. And that is very important. That is the basic step for understanding the climate. So first, you have to do the biostratigraphy. And that is how you know the age of the sediments. And then you look into the ecology, which is like which species were more abundant or more resilient at that time. So, this is this was my work and my work focus more on biostratigraphy and paleoecology of foraminifera in my PhD. In my postdoc, what I do is now that I have all the foraminifera from these sections, and I have done the basic work at Max Planck, I am trying to understand the chemistry of these shells, which tell you about the about the temperatures at which they were formed. The sea surface temperatures at which they were formed. So, I work on stable isotopes and trace elements here. And I try and understand the temperatures 55 million years back.

Nuzhat: 13:12

Okay, that’s really cool. So, you’re working on the same samples?

Sonal: 13:15

Yeah, I work on the same samples.

Jazmin: 13:21

Yeah so, we also know that during your PhD, just before your postdoc, you actually managed to go on an expedition, out to sea. Do you want to talk a little bit more about that?

Sonal: 13:36

Yeah, well, I, I started for the expedition. I mean, the expedition was by the International Ocean Discovery Program, and India is participating nation of that program. So it gave me an opportunity to participate. And then that it was delayed for about a year. But finally, this year, we managed to go there. So, our drilling site was south of New Zealand, and we drill the same Paleogene sediments, but from a very higher latitude site. And the experience was amazing, even though I did get seasick because the motion is like really rough. But it was it was fun when we reached the drilling site, and we started our drilling operations. So as a micropaleontologist, I had to identify the species, various tissues of foraminifera, and basically provide age to the sediments that we were drilling and it was quite a challenging experience because we were on 12 hour duty and shifts. I had night shifts. It was even crazier, but I think we managed well so. That’s a good experience. Yeah. I would love to go there. Go for the expeditions again.

Nuzhat: 15:09

So, what’s it like working on an expedition? Was a very like diverse group in terms of geological abilities, what was your other teammates like?

Sonal: 15:23

Yes, we had a biostratigraphy team, which comprised of not just experts who are working on foraminifera, but other microfossils, like nanoplanktons, and radiolaria. So, as well as there was a geochemist, and there were paleomagnetism specialists and physical property specialists. So, it was a very diverse group. And it was a huge team effort to go there and work. Yeah, so a lot of people from different countries. And that’s how you get to meet all of the different scientists. So, it was amazing experience.

Nuzhat: 16:06

So, if anyone was interested in going on an expedition like this, what kind of advice would you give them?

Sonal: 16:13

Oh, well, I would say that just enjoy yourself and enjoy what you’re doing. Because over there, you will face a lot of- in certain groups, there is a lot of pressure to work. And some you can be relatively relaxed. So if I was a student, I think I would rather be in less in a group, which has lesser pressures, so, yeah. But once you become an expert in it does have its pressure to give the results correctly.

Nuzhat: 16:55

So, the samples that you’ve got from this expedition, are you using them in a way to compare to your studies during your PhD and your postdoc?

Sonal: 17:08

Yes. Well, the samples, as I said, are from higher latitude. And the samples that I have, of the Paleogene sections are from the lower latitudes in India. And thus, I want to compare the temperature changes across different latitudes. And this will be a very good site to compare. So yes, it forms a part of my project.

Nuzhat: 17:35

So, you get like a wholesome picture or more of a more global picture.

Sonal: 17:39

Yeah, I get a more global picture.

Nuzhat: 17:48

So, in terms of we’re gonna go back to studying and geology, so geology in India. What would you say studying paleontology in India is like?

Sonal: 18:01

it is it is a nice subject; it depends on your teachers, I think I was very fortunate to have a great guide and a great teacher. But in general, what I have noticed is that people are not that very interested in paleontology. And I don’t know the reason why, but I think they are less motivated, because it has a lot of fieldwork involved. Because you have to find the perfect samples. And then you have to really, if you want to be a taxonomist, you really have to work a lot, because you basically work for hours throughout your PhD looking under the microscope. So maybe yeah.

Jazmin: 18:49

Would you think it’s maybe not as hands on as like the other geology subjects, maybe? We say it’s more confined being like in the lab, and then on the microscope all the time compared to other geology fields. Maybe that’s why people not that interested in it?

Sonal: 19:11

Yeah, maybe? Yeah, I’m not sure. But yeah.

Nuzhat: 19:17

Okay, so if it’s something that’s declining in popularity, is that something that you’re willing to address? A challenge?

Sonal  19:27

Yeah, it is quite a challenge for me. And I would love to promote that field a lot. And I do that I mean, whenever I go back to India, I try and give some lectures in universities. People are motivated in this subject. And they are fascinated by paleontology. And I hope that the next generation does continue research in this subject because India has a lot of fossils, records, and I think they’re very well preserved. Someone [needs to] work on them.

Nuzhat: 20:03

So, you do a lot of work on forams in India. So, after your work at Max Planck, are you interested in pursuing this research back in India? Or what’s your plan in the future?

Sonal: 20:20

So, hopefully after I complete another year of my postdoc here, I wish to go back to India and start my own research group. And I would love students to get involved in it. And yeah, I will basically be starting a research group which works on deeper timescales on Paleogene. And I would love to explore Cretaceous as well. So yeah, I want to basically go back and be hopefully a permanent faculty in one of the premier institutes, given a chance.

Nuzhat: 20:56

Yeah, it be amazing to see you with your lab one day. Why do you want to study the Cretaceous as well?

Sonal: 21:04

Oh, Cretaceous is an amazing time, because you have the mass extinction. The dinosaurs went extinct at the tertiary boundary. And that is quite a debated topic. Like, why was there [an] extinction? What was the cause of the extinction? And yeah, I would be pretty interested in addressing that next.

Nuzhat: 21:30

All right, that sounds really cool.

Sonal: 21:33


Jazmin: 21:34

Yeah and good luck as well, I hope you do. So, coming near to the end of the episode, and we’d like to give everyone a fun little question. So, your little question is, what is your favorite foram and why?

Sonal: 21:50

Well, my favorite foraminifera is nummulites, it is a larger benthic foraminifera and it is, it can be as tiny as 500 microns and it can grow up to the size of five centimeters or so- [Nuzhat] -Okay. [Sonal] -yeah. And it is yeah, so its growth rate is very, very slow. So, its lifespan can be from few months to few years. And that’s why it can test practically can record changes in the seasonal temperature variations. So is for sure my favorite foram.

Nuzhat: 22:33

Thank you Sonal. Okay, as we wrap up just before we go up, if people wanted to get in touch with you, where is the best place to contact you?

Sonal: 22:44

They can just email me and my email ID is sonal dot k dot one two at gmail dot com (sonal.k12@gmail.com). So, yeah, anyone interested in talking by email, I will try and answer back.

Nuzhat: 23:00

Okay, thank you Sonal for talking with us.

Sonal: 23:03

Thank you Nuzhat. Thank you Jazmin.

Nuzhat: 23:08

Alright. And that’s it from us. If you enjoy this podcast, please like, subscribe, share and leave a review.

Jazmin: 23:18

If you have any feedback for once it gets in touch with us. You can find us on what on earth podcast at gmail dot com or What On Earth Pod on Twitter, or What On Earth Podcast on Instagram.

Nuzhat: 23:31

See you the next time!

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