Meet the…. sedimentologists!

For our next “meet the scientists”, we’re going to be chatting to the absolute most important people on the whole ship. Yes, it’s the sedimentologists*.

And because we are so important, and indeed, because there are 8 of us on Exp. 353, I am going to interview two of them simultaneously! My powers of multi-tasking are indeed profound.

Ladies and gentlemen, I present to you, Sunghan and Kau, who are going to explain what we do on board the JR and why it’s so intensely vital…


Greetings interviewees. So to start us off, can you please introduce yourselves?

SK: My name is Sunghan Kim. I’m the only Korean here on the JR, and a Post-Doc Researcher from Pusan National University, Busan.

KT: I’m Kaustubh Thirumalai, or Kau (pronounced ‘cow’) for short. I hail from Bangalore, India where I was born and brought up. I went on to obtain a bachelor’s degree from the National Institute of Technology Karnataka where I majored in chemical engineering (with a minor in procrastination) at Surathkal, a small college-town on the southwestern coast of India. Currently, I am a PhD candidate at the University of Texas Institute for Geophysics in Austin, Texas, USA.

kau                                  Sunghan

[L: Kau staring down the barrel of a core; R: Sunghan having a great time with the microscope]

Ok, nice to meet you both! What is your specialty on the JR and what does it involve?

SK: Sedimentologist. We have 8 sedimentologists on Expedition 353; do you know what that means? Sedimentologists are involved in the most difficult and important parts of Expedition 353.

KT: For Expedition 353, I am sailing on the JR as a sedimentologist, which is a glorified term for a mud describer. Essentially, my job is to make detailed reports about the cores that continuously come up on deck from the drill floor. This includes distinguishing the sediment’s color, coarseness, composition, and noting down when, where, how and potentially why, changes in these characteristics occur in the cores. For this leg, there are eight sedimentologists (four on each shift) and we all work together to ensure that the cores are described in a consistent manner: the devil is always in the details!

investigation kau

[Kau making sure no devilish details are overlooked!]

Fabulous. So can you tell us why exactly the job of a sedimentologist is so important to the expedition? What does it contribute scientifically?

SK: We provide basic information about core materials for further study. I think the basic information provided by us is the gateway to great science.

KT: Since Expedition 353 is a sediment-heavy mission, the sedimentologists are really important, not only for other working groups aboard, but also for shore-based scientists who would like to obtain a clear idea about what we have drilled. Besides providing descriptions of the core, the eight of us will play a big role in relating the actual sedimentology of the core to the output of different groups including downhole data, physical properties, and age constraints [See later posts for more about these jobs]. Our descriptions can also help the chemists and biostratigraphers in choosing “interesting” sediment sample for their measurements. Stratigraphic correlators can also use our observations in making comparisons between different core-holes at the same location. Most importantly, our reports will help several scientists who would like to sample these sediments for various purposes in the future.
Smear slide prep_1

[The boys being schooled by “smear-slide-Steve” in the ways of the core]

Ok great, and what are your normal areas of research back at home, when you’re not on the JR?

 SK: The fields of paleoclimate and paleoceanography. Using various proxies, I have studied the paleoceanographic/paleoclimatic changes mainly in the high latitudes: Bering Sea, NW and NE subarctic Pacific, and additionally central equatorial Pacific, as part of collaborative projects. I am interested in the regional/local changes and in understanding of the relationship between low and high latitudes.

KT: My normal area of research is in paleoceanography (my abnormal areas of research is reserved for another post). In particular, I try and understand how hot/cold, salty/fresh oceanic waters were in ancient times and why they changed over time. How do I do this? Using small plankton-shells (called “foraminifera”) that record all this information in their chemistry of course! I am very much interested in using geochemical methods that are tried and tested to extract climatic information (like sea-surface temperature and salinity) from these shells that are found in marine sediments. This climatic information can be used to validate complex global climate models that try to simulate future climate considering manmade global warming. Instead of ‘forecasting’ climate, some of these models are ‘hindmost’ to investigate past climates. Only through a marriage of modeling and paleo-data can we truly understand past climatic changes and gain a better handle on future changes that we will see (and are already experiencing).

Ok thanks for the background information fellas. Going back to Exp. 353, what is the scientific question you are most hoping to answer with the new material from the expedition?

SK: I want to understand how paleoproductivity, clay mineralogy, and trace metal distribution changed in relation to the evolving Indian Monsoon? If so, how are they connected? Moreover, I hope to find the connection between changes in the Indian monsoon system and the oceanographic/climatic system in the high latitudes, or the North Pacific, as a final goal.

KT: I would love to get my hands on ‘young’ sediment in the Bay of Bengal. For me, ‘young’ sediment can be anywhere from present to 40,000 years ago. As I mentioned above, there are many climate models that try and simulate past climate over this time – but many of them give different ‘answers’ regarding the strength and sensitivity of the Indian monsoon. Using the geochemistry of foraminiferal shells, I would like to reconstruct monsoonal variability and use the newly generated data to validate and test climate model output during this time period.

Great, well that raps it up for the science part. Now for the nitty gritty… what is the best part about being at sea on the JR?

SK: Communication with other excellent scientists from all different fields. I don’t do Facebook at all, but some friends of mine told me about my photos in the IODP Facebook. So, this kind of thing is also nice just to imagine that people around the world are watching me.


[Sunghan leading us in the Korean version of Silent Night – good job!]

KT: The best part about being at sea on the JR is the people that you meet including the crew, staff, drillers, engineers, technicians, and last, but not least, the scientists! Everyone has an intriguing story as to how and why they ended up here on this one vessel that is seemingly floating in the middle of nowhere!


[Kau and Markus jamming with the JR guitars]

Every silver lining has a cloud. What is the worst part about being at sea on the JR? What do you miss most from home?

SK: I have to be apart from my family. My 11-month daughter and wife. My wife’s birthday was a few days ago and what is more is my daughter’s FIRST birthday is just coming next month. When I go back home after the Expedition, I am sure that my daughter will treat me as a stranger for a few days, weeks, or months? I have no idea. [Aww don’t worry Sunghan, I’m sure she won’t forget you!]

KT: I don’t know if there is a ‘worst’ thing about being at sea – I really enjoy it. But one of the more annoying things is not being able to instantly communicate with your family and friends in today’s smartphone age. Although, I must say, so far on the JR, this has been quite refreshing!

Ok well thanks for taking the time to answer the questions gentlemen. I look forward to continuing to work with you both over the next 5 weeks!

Next time on “meet the scientists”, what do biostratigraphers do and how tiny are microfossils?

*I am in no way biased by the fact that I am a sedimentologist. And even if I was, what are you going to do about it? It’s my blog.


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