Yusuke Kubo

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This transcript is based on a video-recorded interview deposited at MarE3, JAMSTEC (Yokosuka, Japan).

The transcripts of the research project Oral Histories of Scientific Ocean Drilling are polished representations of oral conversations, and are intended solely for the purpose of preserving and documenting personal accounts and memories. They are not a literary product, and are not intended to exhibit literary qualities.

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Interview of Yusuke Kubo by Beatriz Martinez-Rius on 2025 April 3, Kochi Institute for Core Sample Research (Kochi, Japan) [link]

Beatriz Martinez-Rius (BMR): Today is April 3 of 2025. I’m Beatriz Martinez-Rius, historian of science at JAMSTEC, and I’m at the Kochi Institute for Sample Core Research with Yusuke Kubo. Thank you very much.

Yusuke Kubo (YK): Thank you.

BMR: Can you tell me your name, position and affiliation?

YK: I am Yusuke Kubo. I’m currently a IODP core curator at KCC (Kochi Core Center) and I’m also the group leader of the technical support group of Kochi Institute.

BMR: For how long have you been here?

YK: I came here in 2019. So, it’s been six years.

BMR: And before that?

YK: Before that, I worked for CDEX (Center for Deep Earth Exploration), the ship operator of Chikyu, as one of the EPMs (Expedition Project Manager) for Chikyu.

BMR: For many years were you in that position?

YK: From 2007 to 2019 – 12 years, I guess.

BMR: At Yokohama?

YK: Yes, Yokohama.

BMR: What are the differences, for you, about what you were doing in CDEX and what you are doing now?

YK: The biggest difference is that I don’t work offshore, now in Kochi. That’s a big difference, because in CDEX I had an offshore duty as an EPM. There were some cruises every year. Now I can be fixed onshore.

BMR: Is this something positive, for you? Or you also liked to go to the offshore?

YK: For me, it’s positive. I can spend more time with my family, and I don’t need to travel that much.

BMR: Let’s just start chronologically. Where did you grow up? What is your sort of background?

YK: I grew up mostly in Osaka, in the city of Toyonaka. I spent my school years mostly in Osaka, but it included 5 to 6 years in Tokyo, as well. I moved from Osaka to Tokyo, and then back to Osaka.

BMR: Were your parents working for something related to sciences or engineering?

YK: Not at all. My father worked for a pharma company, and his job moved from Osaka to Tokyo, back and forth.

BMR: How did you become interested in Earth sciences?

YK: I liked natural sciences in general, and in my university, my future supervisor at that time gave a very interesting lecture in Earth sciences. That was the first time I became seriously interested in Earth sciences.

BMR: Where did you obtain your degrees?

YK: I took the Bachelor and Master in the University of Osaka, and then moved to Kyoto University for my Ph.D.

BMR: Was there someone relevant or influential for you, during that period?

YK: Yes. Professor Fujio Masuda was my supervisor all through my student period, in Osaka and in Kyoto, as well.

BMR: And how did your research interests develop – I mean, the particular subjects you got interested in?

YK: My supervisor was a very good field geologist, but he did not force me to go out to the field. I liked walking around in the field, doing fieldtrips, but it was not my specialty. I worked more on the computer sciences, so he allowed me to try various things – field work, and computer science, and also laboratory experiments. So, I had a chance to work on various kinds of work. That was a good part.

BMR: And then, how did you know about scientific ocean drilling for the first time?

YK: For the first time – it was very late. I mean, I did not know about scientific ocean drilling during my studentship time. Then, I moved to JAMSTEC as a postdoc, and then moved to another postdoc job at the United States. And after that, I had a chance to talk with CDEX’s director at the time, and that was almost the first time that I knew about scientific ocean drilling.

BMR: So, before that time, were you focused on doing science?

YK: Yeah. Mainly in computer science.

BMR: It’s a very particular background, compared to other people involved in the community.

YK: Right, right. I joined CDEX when I was 35 years old, and I was new to the scientific ocean drilling at that time.

BMR: What attracted you about scientific ocean drilling?

YK: I was invited as an EPM and it sounded interesting to me, to manage the science. I mean, I was a researcher until then, but I changed a little bit the direction from studying myself to managing the scientists. That was interesting, for me. An interesting challenge.

BMR: You said you were experienced in computer science, and then you entered into a community of people who was doing something totally different. What were the differences, in terms of community, type of research, logistics…?

YK: It was totally new, to me (laughs). So, there was nothing in particular – I mean, it was totally different from my previous experiences. It’s a difficult question. I can’t think of anything specific (laughs).

BMR: What kind of things did you had to learn to be an EPM?

YK: Everything. I was new in the drilling science, so drilling technology was all new to me, and how the ship is operated, and how the science party is organized… The scientific part was not too difficult for me, but I had to learn about how drilling takes place on the ship. So, I had a little background of drilling science. That was a very difficult for me, because my colleagues in CDEX were all specialists of drilling, so I was very – like a student, in CDEX.

BMR: Yeah, that’s right. I’ve heard that CDEX was very multidisciplinary from the beginning. How an EPM learns to be an EPM? There’s no master degree about it.

YK: (both laugh). Yeah, right. There was no particular course to study, so I was kicked out into the wild ocean (laughs). I had the chance to join the very first expedition of Chikyu, so that was my first time to participate. I saw how the EPM worked, and I learned from that. So, Moe (Kyaw) was the EPM of that expedition. He was my kind of mentor or tutor.

BMR: Did you later have to mentor someone?

YK: I don’t think so. Lena Maeda joined after me, but she was the only one. And she had more experiences in Chikyu, so there was not too much to show to her.

BMR: Was this your first time offshore, in a scientific ship?

YK: I was a postdoc at JAMSTEC, after I took the PhD, but it was not drilling, it was geophysical survey and geological sampling. I had 3 or 4 times of such cruises. For example, I had a chance to participate in a cruise of seafloor survey using side scan sonar. That was probably the first time I made my study.

BMR: Okay. So, you knew the ocean and the science, but what was new was such a big ship and complex operations.

YK: Yeah.

BMR: And probably, probably, the human management-side of the job.

YK: Yeah.

BMR: For how many expeditions were you EPM?

YK: For IODP cruises, three times.

BMR: You mean, there were other non-IODP cruises?

YK: With Chikyu? Yes, there were some short cruises. Three or four times, short scientific cruise and commercial cruises.

BMR: I thought that the EPM was only a role for IODP cruises.

YK: There is short domestic cruise program called SCORE (Shallow Core Program), and I participated a few times on such short cruises.

BMR: During that period as an EPM, what was the part that you enjoyed the most or liked the most? And what was the toughest part?

YK: Enjoyable part is that I can work with new people every time. It’s good to know new people, and the spend long time onboard, isolated from onshore – family and other friends. So, we spend very dense time onboard. That was the good part.

And the toughest part is… Uhm. Toughest part is when I noticed that someone was not really enjoying the cruise on board, and I wondered how I can help such people. But usually there was not much I could do… So, when I felt like that, it was a very difficult time.

BMR: When I sailed on Chikyu, I realized that being on board is very social. So, as you say it’s dense not only in the work, that of course it is, but also in the relationship with people.

YK: Yeah.

BMR: How did you handle the communication between the science party, the co-chiefs and the operations crew?

YK: It’s very complicated. There various groups onboard the ship. Scientists, technicians, and drilling guys. And, it’s true, EPM is the hub of such various communications.

BMR: Do you remember any example of a case that was a challenge?

YK: Uhm… It’s a long time ago. In my cruises, co-chief scientists were kind of very experienced. They all had previous experiences onboard Chikyu, so the co-chiefs knew how it works and how it’s like. So, that helped me a lot. If they are new to Chikyu, I had to help them much more. But in my cases, the co-chiefs helped me (laughs). That was very helpful for me. And that helped having good communication, because the co-chiefs could communicate with the drillers directly, even without me. So, I didn’t need to help that much. I rather spend more attention to younger people, students or inexperienced technicians. They might have no idea how things go onboard. That was the most difficult part, for me, to pick every little thing for young people.

BMR: During that time, were you also involved in the development of IODP programs? Like the transition from one program to the other, or the international meetings…?

YK: Not that much. I participated in several meetings, like the SEP – the Science Evaluation Panel, and… later, Chikyu IODP board. But I wasn’t responsible in organizing anything or responsible in the program, overall transition.

BMR: Oh, okay. You started in the very beginning of Chikyu, twenty years ago. In your view, how has been the evolution of IODP?

YK: In early years, Chikyu had more expeditions. I mean, they had more cruise time, a few expeditions a year. In 2007, there were three expeditions a year and another new expedition every year. But recently, Chikyu has IODP cruises once every other year. So, that makes it very difficult to improve something or have some consistency or continuity. I guess that was a very difficult part for the current member of the ship operators.

BMR: Does it also affect the functioning of Kochi Core Center?

YK: I don’t know the functioning of the KCC in the early years. I think they had more difficult times when they received a lot of cores. But I knew about KCC only recently, when there is not too much new cores coming. I don’t know, but I guess they struggled with receiving such many cores every time. They built a new repository in 2013. So, I think it was very challenging expanding this facility.

BMR: Focusing on these years that you were on CDEX, is there any particular story that you’d like to explain, about the period you were EPM?

YK: I had participated in three IODP expeditions as an EPM, and each expedition has a different experience and different memories. The first one was the very first for me, so everything was new to me… I had a very strong impression from that expedition. And the second was the most technically challenging expedition. It was a riser expedition offshore the Tohoku area. And we needed to rebuild the laboratory for the riser operation and for microbiology studies. So, it was very challenging, for me. And the third was another unique expedition, in which Chikyu collaborated with the KCC. Chikyu sent samples to KCC for immediate onshore analysis, and the data was sent back to Chikyu. So, we had a close collaboration between onshore KCC and offshore Chikyu. It was a very unique kind of expedition. Yeah, each one of them has very strong memory on me.

BMR: Is there something of those expeditions that now, looking back in time, you think “we should have done this differently”? Or, “that was a very good decision to make, and that’s why we succeed”?

YK: Uhm… My second expedition, IODP Expedition 337 – that was the riser expedition offshore Tohoku area. That expedition was suspended by the earthquake in 2011. The expedition was originally planned in March 2011, but the earthquake happened just before the start of the expedition, and we had to postpone the expedition to next year. If the expedition had started as scheduled, I guess it would had been a disaster (laughs), miserable failure. I wasn’t ready, and the entire laboratory wasn’t ready to implement the very difficult laboratory work… I cannot say it was fortunate to have the earthquake but, if the expedition was implemented as scheduled… I don’t want to imagine about that. But a year later, we were more ready and we could better prepare for that. So, I think the expedition was successful, at the end. That was the very good side of the story (laughs).

BMR: Yes, it’s a sort of “lucky” coincidence – well, it’s hard to call it lucky… It’s quite impressive, actually, because I feel that you learned so many things, being an EPM. What you just said about laboratories, I guess you were implementing microbiology labs, so very specific systems. I imagine that you needed to have very close interaction with people who is experienced in laboratory set up, but at the same time maybe you need to make decisions, also, as an EPM.

YK: Yeah. As for the microbiology part, I didn’t know much about microbiology at all. But the expedition worked with the microbiologists of KCC, so we could have a very close and good communication within JAMSTEC. That helped me a lot.

BMR: At which moment did you decided to move to Kochi? How it happened?

YK: I moved to Kochi in 2019, and I had the third EPM expedition in 2017 or 2016. After that, I felt I wanted to spend more time with my family. At that time, my dog was getting old and I wanted to stay with her. And once I go offshore, I spend offshore two months or even longer, and I thought that I didn’t want that. I thought about getting a position for onshore work, and I thought a position at the KCC was the best for me.

BMR: When you came to KCC, what kind of position were you in?

YK: I was an IODP core curator.

BMR: And how did you learn about being a core curator?

YK: The job of core curator was nicely set up by my previous IODP curator, Lallan (Gupta). He made everything very nice and sorted out. So, he showed me how the curator works. He stayed in KCC for a few months after I moved here, so we could work together and he showed me a how it’s like.

BMR: What kind of things did you need to do, as core curator?

YK: Reviewing sample requests, and working with technicians and curation staff, to take actual samples and send those samples to the sample requesters. That was the main part of curators’ work.

BMR: And thinking in terms of the scientist who request samples. What’s the percentage of people in Japan and overseas?

YK: Roughly 20% is Japanese scientists, and the remaining 80 is from other parts of the world.

BMR: And how is this supported, economically? Do requesters need to pay for the samples, or the shipping?

YK: It’s totally free of charge. JAMSTEC pays the necessary costs of taking the sample and send the samples to the requesters. So, IODP sample requesters pay nothing.

BMR: It’s a good business for them. What kind of things you find more interesting about the work of core curators?

YK: Some of the sample requesters visit the KCC to sample by their own or for core observation. So, it’s nice to work with such visiting researchers. We don’t need to hassle too much, I mean, like on board. We have more time, and they know already what cores we have and the basic data is all available, so we can have more deep thinking, in a more relaxed environment. That’s a good part.

BMR: What kind of things did you learn as an EPM that in your core curator job have been useful?

YK: When I was an EPM I worked with curators, of course. I knew some of the curators’ work, so it was not too difficult for me to shift from the EPM role to curator role. And I know how it’s like to work on board. So, when we receive samples from the Chikyu, I can imagine how the science party worked with the core previously, and some of the remaining tasks from the ship to the core repositories. I think I can handle such a crossover, between the ship and the repository.

BMR: Are you now managing also people?

YK: I’m group leader of technical support group. Yes.

BMR: Is this a more challenging work, do you think, than just handling cores and requests?

YK: I’m new in this role, so I still don’t know if I can do it good or not (laughs) but yeah, the main work of this group is the core curation. Not only IODP, but also other JAMSTEC cores. As for core curation, I know how it’s like. So, it’s not too difficult, for me. And the people in this group are all friendly and of course, I know everyone. I’ve spent six years here. So, it’s not too challenging for me.

BMR: Do you have any views on the direction you want to develop your job, now? Something that you’d like to change or move forward?

YK: I think the demand for cores in the repository is increasing. I mean, the US drillship terminated the operations, and we have a smaller number of expeditions of scientific ocean drilling. So, the scientists want to use the cores in the repository more than ever. So, I think our core repository can contribute much more than we did before. And, there are new technologies in the laboratories, so I hope we can help the community to develop such new technologies.

BMR: Besides the technical group, here in the KCC there’s also a scientific group of researchers, PhDs and postdocs. How is the relationship, working between both teams?

YK: Some of the scientists work on core samples, so we have direct collaboration with such scientists. And our group is also responsible in contracting the technicians for the research group. So, we have such contribution, as well. There are professors of Kochi University, as well, and they use core samples, and we share some of the analytical instruments. So, we collaborate with university people, as well.

BMR: Do you also collaborate with the other international core repositories?

YK: Yes. There are two other repositories, one in Texas and the other in Bremen, and we work with the same protocols, and we are supposed to provide the same consistent services between all three repositories. So, we have a good communication between the core repositories, and when there are any issues, we discuss among us.

BMR: I didn’t know that there were like meetings of the core repositories.

YK: Yeah. There used to be a curators meeting, I’ve heard, but recently there is no regular meetings. But we had a chance to meet in the last IODP Forum meeting, held in Shizuoka. We three had a chance to discuss some issues, and one of them, the curator at Texas, visited the KCC after that.

BMR: What has been something that you consider especially important or relevant for your life, for your career, about these years that you have been involved in scientific ocean drilling?

YK: Right now, in the future…?

BMR: How do you prefer to answer? (laughs)

YK: (laughs) Right now, I’m focusing on making more contributions from the core repositories, like encouraging the use of repository cores and developing new technologies. And for the future, it’s important to continue and increase such contributions. But, in the future, I think we are approaching to the end of operating Chikyu. So, that’s a very interesting topic. How we can close out Chikyu’s life successfully.

BMR: And what do you think?

YK: Currently, no particular idea. I’ve heard that Chikyu will continue operations until 2040. So, that’s too far for me to expect something. And I think I will be already retired, at that time (laughs). I don’t think I’ll responsible for the real close out, but I’m conscious, I’m aware that we are approaching to that direction. So, we will be working with the community, on how we will be moving to that direction.

BMR: I have one last question. Why the cores are important?

YK: That’s probably one of the best collections of geological samples all over the world. It’s taken from various environments, and curated nicely, and stored carefully. That’s probably the best collection to study the Earth sciences. And I’m glad that I’ve been involved in such community.

BMR: That’s great. So, finally, is there something else you want to add that we have not talk about?

YK: Uhm… Not really. I will show you the core repository after this.

BMR: Yes, thank you very much. It’s been a pleasure.