Yoshiaki Endo

CV

Employment

Jun 2023 - : Project assistant professor at Department of Earth and Planetary Sciences, Tokyo Institute of Technology

Oct 2022 - May 2023 : Postdoctoral Researcher at Earth Surface System Research Center, Research Institute for Global Change, The Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Japan (supervised by Dr. Yugo Kanaya)

Feb 2022 - Sep 2022 : JSPS Overseas Research Fellow at School of Earth and Environmental Sciences, University of St Andrews, Scotland (supervised by Dr. Mark W. Claire)

Apr 2019 - Feb 2022 : Research Staff at Earth-Life Science Institute, Tokyo Institute of Technology, Japan (supervised by Dr. Yasuhito Sekine)

Sep 2019 - Feb 2020 : Visiting scholar at School of Earth and Environmental Sciences, University of St Andrews, Scotland (supervised by Dr. Mark W. Claire)

Apr 2016 - Mar 2019 : JSPS Research Fellow (DC1)

Education

Apr 2016 - Mar 2019 : PhD student, Earth and Planetary Sciences, Tokyo Institute of Technology (supervised by Dr. Yuichiro Ueno), My doctoral thesis title is "Experimental study on sulfur mass-independent fractionation during SO2 photochemistry and its application to Archean atmosphere"

Apr 2012 - Mar 2014 : M.S. Earth and Planetary Sciences, Tokyo Institute of Technology

Apr 2008 - Mar 2012 : B.S. Earth and Planetary Sciences, Tokyo Institute of Technology

(Apr 2014 - Feb 2016 : Working for a private company)

Research interests

My research interests are exploring 1) isotope fractionation mechanisms based on physics and chemistry and 2) early Earth environments.

1) Isotope fractionation during photodissociation is determined by isotopologue absorption spectra and incident photon spectra. We measured high-precision absorption cross-sections including 36S whose abundance is only 0.02 %. We estimated fractionation factors (δ34S, Δ33S, Δ36S) during SO2 photodissociation (Endo et al. 2015).

Commentary: Rare sulfur isotopes (36S) providing a clue to decode Earth's early atmosphere

www.titech.ac.jp/english/news/2015/032471.html

The measured absorption spectra of 32SO2, 33SO2, 34SO2, and 36SO2.

→ Using the absorption spectra reported by Endo et al. (2015), sulfur isotope compositions of atmospheric sulfur species were calculated by a 1-D atmospheric model (Izon et al. 2017).

Reference: Izon, G., Zerkle, A. L., Williford, K. H., Farquhar, J., Poulton, S. W., & Claire, M. W. Biological regulation of atmospheric chemistry en route to planetary oxygenation, PNAS, 114 (13) E2571-E2579

https://www.pnas.org/content/114/13/E2571.short

Next, we examined isotope fractionations by SO2 photochemical experiments. Experiments are conducted under optically thin SO2 conditions. The results showed that [1] Δ33S and Δ36S by photodissociation values depend on column density of SO2 (self-shielding*) and [2] photoexcitation chemistry causes very large 33S fractionation, Δ33S=+140 ‰. By mixing [1] and [2], the character of Archean sulfur isotopes (Δ36S/Δ33S~−1) can be reproduced (Endo et al. 2016). Experiments were conducted at various total pressures from 0.025 to 1.7 bar and the observed Δ33S and Δ36S values were found to strongly depend on total pressure. Because the Δ33S and Δ36S values depend on SO2 gas's absorption line width, we concluded that the total pressure dependence comes from by pressure broadening of SO2 absorption lines (Endo et al. 2019).

*Self-shielding: Isotope fractionation owing to UV spectra change by SO2 own absorption

Moreover, (A) based on the Δ33S and Δ36S relationship, it is speculated that SO2 was photolyzed at low pressure like upper atmosphere; (B) absorption line width depends on not only pressure but also temperature; (C) it is possible that isotope fractionation reproduces also δ34S at low temperature and low pressure limit. Extending Endo et al. (2019), I'm trying low temperature experiments now. (Supported by KAKENHI "Reconstructing ancient atmospheric composition using temperature dependence of sulfur isotope fractionation.") These research is a unique combination of physical chemistry and earth history and it is very interesting!

2) Early Earth (before 2.5 billion years ago) environment is linked to evolution of solid earth and origin of life and evolution. It is known to be reducing and oxygen-free atmosphere, which is completely different from present atmosphere. But other information has been poorly understood. In order to reveal Earth's early atmospheric chemistry, I focus on sulfur mass-independent fractionation (S-MIF) in Archean sedimentary rocks.

Because reactions which cause MIF are very limited, MIF is strong proxy to constrain physical and chemical parameters at that time. The most important character of Archean MIF is that the slope of Δ36S/Δ33S is −1. We compared the numerical calculation including MIF by our study with geological Δ36S/Δ33S trends and estimated that Archean atmosphere contained several percent of CO or CH4 gas (Endo et al. 2016).

Publications

Peer review paper

8. Li, Y., Danielache, S. O., Endo, Y., Nanbu, S., & Ueno, Y. "High-Resolution UV Absorption Cross-section Measurements of 32S, 33S, 34S, and 36S Sulfur Dioxide for the B ̃1B1-X ̃1A1 Absorption Band." accepted in ACS Earth and Space Chemistry

7. Endo, Y., Chen, M., & Claire, M. W. "An analysis of Δ36S/Δ33S dependence on definitions of sulfur mass-independent fractionation." Chem. Geol., 609, 121064. https://doi.org/10.1016/j.chemgeo.2024.122157

6. Endo, Y., Sekine, Y., & Ueno, Y. (2022) "Sulfur mass-independent fractionation during SO2 photolysis in low-temperature/pressure atmospheres." Chem. Geol., 609, 121064. https://doi.org/10.1016/j.chemgeo.2022.121064

5. Endo, Y., Danielache, S. O., Ogawa, M. & Ueno, Y. (2022) "Absorption spectra measurements at ~1 cm−1 spectral resolution of 32S, 33S, 34S, and 36S sulfur dioxide for the 206−220 nm region and applications to modeling of the isotopic self-shielding." Geochem. J., 56(1), 40–56. https://doi.org/10.2343/geochemj.GJ22004

4. Endo, Y., Danielache, S. O., & Ueno, Y. (2019). "Total pressure dependence of sulfur mass-independent fractionation by SO2 photolysis." Geophys. Res. Lett., 46(1), 483−491. https://doi.org/10.1029/2018GL080730

3. Endo, Y., Ueno, Y., Aoyama, S., & Danielache, S. O. (2016). "Sulfur isotope fractionation by broadband UV radiation to optically thin SO2 under reducing atmosphere." Earth Planet. Sci. Lett., 453, 9−22. https://doi.org/10.1016/j.epsl.2016.07.057

2. Ueno, Y., Aoyama, S., Endo, Y., Matsu'ura, F., & Foriel, J. (2015). "Rapid quadruple sulfur isotope analysis at the sub-micromole level by a flash heating with CoF3." Chem. Geol., 419, 29−35. https://doi.org/10.1016/j.chemgeo.2015.10.032

1. Endo, Y., Danielache, S. O., Ueno, Y., Hattori, S., Johnson, M. S., Yoshida, N., & Kjaergaard, H. G. (2015). "Photoabsorption cross-section measurements of 32S, 33S, 34S, and 36S sulfur dioxide from 190 to 220 nm." J. Geophys. Res. Atmos., 120(6), 2546−2557. D021671. https://doi.org/10.1002/2014JD021671

Presentations (international conferences)

(1st author only)

10. Endo, Y., Danielache, S. O., Ogawa, M., & Ueno, Y. "Sulfur mass-independent fractionation in SO2 photolysis: comparison between absorption spectra measurements and photolysis experiments of SO2." Goldschmidt Conference 2023, Lyons (France), 2023/07 [GSJ Medal Lecture] https://doi.org/10.7185/gold2023.19054

9. Endo, Y. "Multiple sulfur isotope fractionation during SO2 photolysis: A synthesis of absorption spectra measurements and photolysis experiments of SO2." 1st China-Japan Youth Joint Forum on Geochemistry, Virtual, 2022/05 [Invited talk]

8. Endo, Y., Claire, M., Harman, C., Crick, L. "New sulfur isotopes 1-D photochemical model for revealing early earth's atmosphere." JpGU-AGU Joint Meeting 2020, Virtual, 2020/07 [poster]

7. Endo, Y., Danielache, S.O., Ueno, Y. "Total pressure effect on mass-independent fractionation of sulfur isotopes: laboratory experiment of SO2 photochemistry." Goldschmidt Conference 2018, Boston (USA), 2018/08 [oral]

6. Endo, Y., Ogawa, M., Danielache, S.O., Ueno, Y. "Measurements of 32SO2, 33SO2, 34SO2 and 36SO2 high-resolution cross-sections and isotope effects by SO2 self-shielding." 2017 AGU Fall Meeting, New Orleans (USA), 2017/12 [poster]

5. Endo, Y., Ogawa, M., Shinkai, M., Danielache, S.O., Ueno, Y. "High-resolution 32/33/34/36SO2 absorption cross-section measurements for revealing Archean atmospheric composition." JpGU-AGU Joint Meeting 2017, Chiba(Japan), 2017/05 [oral]

4. Endo, Y., Ueno, Y., Aoyama, S., Danielache, S.O. "Experimental study on SO2 photochemistry under reducing atmosphere and S-MIF." Goldschmidt Conference 2016, Yokohama (Japan), 2016/06 [poster]

3. Endo, Y., Danielache, S.O., Ueno, Y. "Experimental study of sulfur isotope fractionation by SO2 photolysis." 2nd ELSI International Symposium, Tokyo (Japan), 2014/03 [poster]

2. Endo, Y., Danielache, S.O., Ueno, Y., Hattori, S., Johnson, M.S., Kjærgaard, H.G. "Pressure-dependent change of ultraviolet absorption cross section of SO2 isotopologues and S-MIF." Goldschmidt Conference 2013, Florence (Italy), 2013/08 [poster]

1. Endo, Y., Danielache, S.O., and Ueno, Y. "Experimental study of S-MIF by SO2 photolysis under CO atmosphere." Goldschmidt Conference 2012, Montreal (Canada), 2012/06 [poster]

Awards

3. Geochemical Journal (GJ) Award 2023 https://geochemical-journal.jp/pages/view/gj

2. JpGU 2018 Outstanding Student Presentation Award (Biogeosciences Section)

1. Outstanding student award of master thesis in Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2013

Grants and scholarships

6. Grant-in-Aid (KAKENHI) for Young Scientist, "Influence of oceanic pH on atmospheric composition in Earth-like Planets: Insights from deposition rate constants." Apr 2025 - Mar 2029 (4.68 M JPY)

5. Astrobiology Center, Project research, "Carbon monoxide-rich planetary atmospheres as an anti-biosignature.",Apr 2024 - Mar 2025 (2 M JPY)

4. Grant-in-Aid (KAKENHI) for Young Scientist, "Reconstructing ancient atmospheric composition using temperature dependence of sulfur isotope fractionation." Apr 2020 - Mar 2023 (4.16 M JPY)

3. Study abroad system supported by Tokyo Tech, Sep 2019 - Feb 2020. (I stayed at St Andrews, Scotland)

2. Grant-in-Aid (KAKENHI) for JSPS Fellows, "Estimation of early Earth's air pressure using pressure dependence of isotope anomaly." Apr 2016 - Mar 2019 (3.2 M JPY)

1. Kobayashi scholarship society, Apr 2008 - Mar 2012 (1.2 M JPY)

E-mail: endo.y.ac_at_m.titech.ac.jp

Links

Google scholar

scholar.google.co.jp/citations?user=K8RUllUAAAAJ&hl=ja

ORCID

https://orcid.org/0000-0002-9750-7996

Department of Earth and Planetary Sciences, Tokyo Institute of Technology

https://educ.titech.ac.jp/eps/eng/

Google Sites

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