Research Interests 

The planktonic ecosystem (nutrient–phytoplankton–zooplankton cycles: phytoplankton take up inorganic nutrients, zooplankton feed on phytoplankton, and both phytoplankton and zooplankton excrete waste matter to the inorganic nutrient pool) is an essential part of marine environments. It is known that the structure of the planktonic ecosystem is highly sensitive to climate and environmental changes, we however have a very limited understanding of how such changes affected, are affecting, or will affect the planktonic ecosystem in aquatic environments.
During the Ph.D. course at Hanyang University, I investigated the structural changes in the planktonic ecosystem through the trophic position of zooplankton and sinking particles and their dynamics with climate and environmental changes. The investigation was carried out mainly via ecological observation of plankton community in fields and chemical analysis of stable nitrogen isotope ratios within amino acids from these species.
I have experienced field works in the Arctic Ocean, Pacific Ocean, and coastal areas of South Korea, as follows:

• 2021, EARDO cruise (South Sea of Korea), 15 June – 18 June
• 2020, ISABU cruise (western Pacific Ocean), 15 May – 8 June
• 2019, ARAON cruise (ARA10B, western Arctic), 3 August – 27 August
• 2019, Arctic Dasan Station (NICE19A, Kongsfjorden, Svalbard), 2 July – 18 July
• 2018, Arctic Dasan Station (NICE18A, Kongsfjorden, Svalbard), 3 April – 19 April
• 2017, Arctic Dasan Station (NICE17B, Kongsfjorden, Svalbard), 11 October – 25 Octobe

After the Ph.D. course, I would like to further focus on improving my technical skills in the compound-specific isotope analysis of organic compounds. For this purpose, I am now working at IsoPEG lab, Hokkaido University, on the development of a new method for measuring carbon isotope ratios of sugars (monosaccharides) in biological samples (including plankton), which is supported by the project from the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT, RS-2023-00239178).

Skills 

Chemical and instrumental analyses

• Gas chromatography-mass spectrometer (GC-MS)
• Gas chromatography-flame ionization detector (GC-FID)
• GC 2010-GCMS-QP2010 (Shimadzu, Japan)
• GC 7890A, 7890B-5977B MSD, 7820A-5977E MSD (Agilent, US)
• Elemental analyzer-Isotope ratio mass spectrometer (EA-IRMS)
• Euro 3000 – Isoprime (Elementar, Germany)
• Vario Select – ViSION (Elementar, Germany)
• Gas chromatography-Isotope ratio mass spectrometer (GC-IRMS)
  HP 6890N (Agilent, US) – Isoprime 100 (Elementar, Germany)
  7890A GC (Agilent, US) – ViSION (Elementar, Germany)
• Spectrophotometer (Cary 100, Agilent, US)

Publications in Journals 

2023

• Park, N., Choi, H., Lee, W., and Shin, K.-H. Distributional pattern of siphonophore in the Northwest Pacific Ocean depending on ambient environment. Submitted to Frontiers in Marine Science.
• Choi, H., Yang, E. J., Kang, S.-H., Kim, D., and Shin, K.-H. Seasonal dynamics of organic matter revealed by nitrogen isotope ratios of amino acids in sinking particles in the Pacific Arctic Ocean. Marine Chemistry. 253, 104252.

 
2022

• Kim, J., Yun, H. Y., Won, E.-J., Choi, H., Youn, S.-H., and Shin, K.-H. (2022). Influences of Seasonal Variability and Potential Diets on Stable Isotopes and Fatty Acid Compositions in Dominant Zooplankton in the East Sea, Korea. Journal of Marine Science and Engineering. 10, 1768.Yoon, D.-S., Choi, H., Sayed, A, E.-D, H., Shin, K.-H.,
• Yim, J, H., Kim, S., Lee, M.-C., and Lee, J. S. (2022). Effects of temperature and starvation on life history traits and fatty acid profiles of an Antarctic copepod Tigriopus kingsejongnesis. Regional Study of Marine Science, 57, 102743.
• Choi, H., Choi, B., Takano, Y., Kim, H., Lee, K., Lim, D.-I., and Shin, K.-H. Microbial alteration in marine sediments: insights from Compound-specific isotopic compositions of amino acids in subseafloor environments. Frontiers in Marine Science, 9:1030669.
• Yoon, D.-S., Byeon, E., Kim, D.-H., Lee, Y., Choi, H., Park, H. G., Sayed, A, E.-D, H., Shin, K.-H., Lee, M.-C., and Lee, J. S. (2022). Genome-wide identification of fatty acid synthesis genes, fatty acid profiles, and life parameters in two freshwater water flea Daphnia magna strains. Comparative Biochemistry and Physiology, Part B, 262, 110774.
• Choi. H., Hwang, J., Ryu, Y., Kim, G., and Shin, K.-H. (2022) Seasonal trophic dynamics of sinking particles in the Ulleung Basin of the East Sea (Japan Sea): An approach employing nitrogen isotopes of amino acids. Frontiers in Marine Science, 9:824479.
• Lee, M.-C., Yoon, D.-S., Park, J. C., Choi, H., Shin, K.-H., Hagiwara, A., Lee, J.-S. and Park, H. G. (2022). Effects of salinity and temperature on reproductivity and fatty acid synthesis in the marine rotifer Brachionus rotundiformis. Aquaculture, 546, 737282.

 
2021

• Choi, H., Won, H., Kim, J.-H., Yang, E. J., Cho, K. H., Lee, Y., Kang, S.-H., and Shin, K.-H. (2021). Trophic dynamics of Calanus hyperboreus in the Pacific Arctic Ocean. Journal of Geophysical Research: Oceans 126, e2020JC017063.

 
2020

• Lee, M.-C., Yoon, D.-S., Lee, Y., Choi, H., Shin, K.-H., Park, H. G., and Lee, J. S. (2020). Effects of low temperature on longevity and lipid metabolism in the marine rotifer Brachionus koreanus, Comparative Biochemistry and Physiology – Part A, 250, 110803.
• Lee, M.-C., Choi, H., Park, J. C., Yoon, D.-S., Lee, Y., Hagiwara, A., Park, H. G., Shin, K.-H., and Lee, J.-S. (2020). A comparative study of food selectivity of the benthic copepod Tigriopus japonicus and the pelagic copepod Paracyclopina nana: A genome-wide identification of fatty acid conversion genes and nitrogen isotope investigation. Aquaculture, 521, 734930.
• Choi, H., Ha, S. Y., Lee, S., Kim, J. H., and Shin, K. H. (2020). Trophic Dynamics of Zooplankton Before and After Polar Night in the Kongsfjorden (Svalbard): Evidence of Trophic Position Estimated by δ15N Analysis of Amino Acids. Frontiers in Marine Science, 7:489.
• Yun, H. Y., Lee, D. H., Choi, H., Won, E., and Shin, K. H. (2020). Evaluation of the quantity and the carbon isotopic composition of amino acids by using diverse sample residues after lipid extraction. Analytical and Bioanalytical Chemistry, 412(18), 4383-4391.

 
2019

• Lee, M.-C., Park, J. C., Yoon, D.-S., Choi, H., Kim, H.-J., Shin, K.-H., Hagiwara, A., Han, J., Park, H. G., and Lee, J.-S. (2019). Genome-wide characterization and expression of the elongation of very long chain fatty acid (Elovl) genes and fatty acid profiles in the alga (Tetraselmis suecica) fed marine rotifer Brachionus koreanus, Comparative Biochemistry and Physiology – Part D, 30, 179-185.
• Lee, M.-C., Fonseca, E., Park, J. C., Yoon, D.-S., Choi, H., Kim, M., Han, J., Cho, H.-S., Shin, K.-H., Santos, M. L., Jung, J.-H., Castro, L. F. C., and Lee, J.-S. (2019). Tributyltin Affects Retinoid X Recepter-Mediated Lipid Metabolism in the Marine Rotifer Brachionus koreanus. Environmental Science and Technology, 53, 7830-7839.
• Kim, D., Hong, S., Choi, H., Choi, B., Kim, J., Khim, J. S., Park, H., and Shin, K.-H. (2019). Multimedia distributions, bioaccumulation, and trophic transfer of microcystins in the Geum River Estuary, Korea: Application of compound-specific isotope analysis of amino acids. Environmental International, 133, 105194.
• Lee, M.-C., Park, J. C., Yoon, D.-S., Choi, H., Shin, K.-H., Kim, H.-J., Hagiwara, A., and Lee, J.-S. (2019). Lipid metabolism modulation by five different food types in the monogonont marine rotifer Brachionus koreanus. Aquaculture, 503, 596-601.

Presentations in International conferences 

Oral presentation
2023

• Choi, H., Kim, S., Wi, J., Sin, Y., and Shin, K.-H. (2023). Short-term variations in trophic dynamics of zooplankton in response to freshwater discharge in a highly altered estuary. The Association for the Sciences of Limnology and Oceanography (ASLO). Palma de Mallorca, Spain.

2022

• Choi, H., Choi, B., Kim, J.-H., Park, N., Won, H., Yang, E. J., Kim, M.-S., Lee, Y., and Shin, K.-H. (2022). Nitrogen isotope baseline isoscape using amino acid nitrogen isotope of copepod Calanus. PICES-2022. Busan, Korea.
• Choi, H., Seong, S., Park, N., Lee, S., Kim, D., Lee, W., and Shin, K.-H. (2022). Inter- and Intra-species trophic variability of copepods in the Korea Strait. International Symposium on Isotope Physiology, Ecology, and Geochemistry (IsoPEG). Sapporo, Japan.

2019

• Choi, H., Ha, S.-Y., Lee, S., Kim, J.-H., and Shin, K.-H. (2019). Trophic position of zooplankton in the polar night of the Kongsfjorden (Svalbard) revealed by δ15N analysis of amino acid. International Symposium on Isotope Physiology, Ecology, and Geochemistry (IsoPEG). Sapporo, Japan.

2017

• Choi, H., Choi, B., Chikaraishi, Y., Kim, M., and Shin, K.-H. (2017). Trophic position assessment in open and closed estuarine ecosystem after rainy season using compound-specific isotope analysis of amino acids. The Association for the Sciences of Limnology and Oceanography (ASLO). Honolulu, Hawaii, USA.

 
Poster presentation
2019

• Choi, H., Choi, B., Kim, H., Lee, K., Lim, D.-I., and Shin, K.-H. (2019). Assessment of Microbial alteration in marine sediments: Evidence from compound-specific isotope analysis of amino acids. International Meeting on Organic Geochemistry. Gothenburg, Sweden.
  

2018

• Choi, H., Choi, B., Chikaraishi , Y., Takano, Y., Kim, H., Lee, K., Lim, D.-I., and Shin, K.-H. (2018). A changing nitrogen source for phytoplankton in the central Yellow Sea revealed by Compound-Specific Isotope Analysis of amino acids. Ocean Sciences Meeting. Portland, Oregon, USA.