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Shiah, Fuh-Kwo夏復國

Research Fellow

Research Interests

My research lies in the fields of limnology and oceanography. I am interested in studying (1) the growth controlling mechanisms of planktons (heterotrophic bacterioplankton, phytoplankton, protozoan and viruses) and their eco-linkages in freshwater (the Fei-Tsuei reservoir) and marine (the East China Sea, South China Sea and the NW Pacific) ecosystems; (2) the planktonic and ecosystem responses (ratio of primary production to community respiration) to external physical and chemical (inorganic nutrients, organic substrate) forcing induced by episodic events such as typhoons, internal waves… etc., and (3) the operation and management of decadal time-series biogeochemical observatory studies including the SEATS project in the South China Sea and the T-WEBS project in Fei-Tsuei reservoir in northern Taiwan.

Representative Publications

  1. Ko CY, CC Lai, HH Hsu, FK Shiah*. 2017. Decadal phytoplankton dynamics in response to episodic climatic disturbances in a subtropical deep freshwater ecosystem. Water Research 109: 102-113.

  2. Lai CC., CY Ko, E Austria and FK Shiah*. 2021a. Extreme weather events enhance DOC consumption in a subtropical freshwater ecosystem: a multiple-typhoon analysis. Microorganisms. 9(6): 1199 doi.org/10.3390/microorganisms9061199.

  3. Lai CC, CR Wu, CY Chuang, JH Tai, KY Lee, HY Kuo and FK Shiah*. 2021b. Phytoplankton and bacteria responses to monsoon-driven water masses mixing in the Kuroshio off the East coast of Taiwan. Frontiers in Marine Science. doi: 10.3389/fmars.2021.707807.

  4. Chen TY, CC Lai, JH Tai, CY Ko and FK Shiah*. 2021. Diel to seasonal variation of picoplankton in the tropical South China Sea. Frontiers in Marine Science. doi: 10.3389/fmars.2021.732017.

  5. Hou LT, BS Wang, CC Lai, TY Chen, YY Shih, FK Shiah* and CY Ko*. 2022. Effects of the mixed layer depth on phytoplankton biomass in a tropical marginal ocean: a multiple timescale analysis. Earth's Future. dx.doi.org/10.1029/2020EF001842.

  6. Chang CW, T Miki, H Ye, S Souissi, R Adrian, O Anneville, S Ban, Y Be'eri-Shlevin, YR Chiang, H Feuchtmayr, G Gal, S Ichise, M Kagami, M Kumagai, X Liu, S Matsuzaki, MM Manca, P Nõges, R Piscia, M Rogora, FK Shiah, SJ. Thackeray, H Agasild, CE Widdicombe, JT Wu, T Zohary, CH Hsieh. 2022. Causal networks of phytoplankton diversity and production are modulated by environmental context. Nature Communications. 13:1140. doi.org/10.1038/s41467-022-28761-3.

  7. Shiah FK, CC Lai, TY Chen, CY Ko & CW Chang. 2022. Viral shunt induced bacterial growth in tropical open ocean. Science Advances DOI: 10.1126/sciadv.abo2829

Highlights

Viral shunt in tropical oligotrophic ocean
Marine heterotrophic bacteria respire on a daily basis an amount of organic matter equivalent to about half the total marine primary production. The viral shunt hypothesis initiated in the 1990’s sug-gested that the viral-lysis might lessen the transfer of bacterial cells to protozoans; the lysate released from the broken cells stimulated the growth of the existing bacteria. For more than two decades, the hypothesis’s development has been based on the results of lab experiments and modeling only, its ap-plicability to nature has not been documented. To answer that question, we conducted 9 anchored sur-veys in the SEATS station of the tropical South China Sea from 2010 to 2017. The results suggest that the timescale adopted in sampling and system trophic status determine the “visibility” of the viral shunt in the field. Specifically, viral abundance (VA), bacterial biomass (BB) and bacterial specific growth rate (SGR) varied synchronously and presented the significant VA-BB and VA-SGR linkages at an hourly scale, which reveals direct interactions between viruses and their hosts. Moreover, this study also observed differential responses of the viral shunt to temperature, i.e., looser VA-SGR coupling in warm and tighter VA-SGR coupling in cold environments, which implies an altered carbon cycling in tropical oceans under climatic warming. In conclusion, this study not only solves a more than 20 years puzzle but also proposes a new hypothesis (i.e. temperature drives different VA-SGR coupling modes) that is worth further examination. Reference: Shiah et al., 2022.
 
Effects of the mixed layer depth on phytoplankton biomass in a tropical marginal ocean: a multiple timescale analysis
Given that ocean stratification, corresponding to mixed layer depth (MLD), is critical of phytoplankton growth and biomass variations under climate change, particularly in tropical and subtropical regions, it is important to examine MLD influences on phytoplankton at multiple temporal scales in those areas. Based on long-term investigation of the SEATS station during the 1999–2019 period. The results indicated that high phytoplankton biomass represented by chlorophyll-a (Chl-a) concentrations, occurred in the cold season and typhoon disturbance could play an important role in increasing oceanic production. For the first time, the inter-annual and decadal observations in the tropical ocean showed a progressive increase in sea surface temperature and decreases in both MLD and Chl-a concentrations that may become a severe environmental and biotic crisis in the SCS. To better address contemporary climatic threats, measurements of phytoplankton responses in the euphotic zone remain essential and may not be simply replaced by recent satellite remote sensing development. Reference: Hou et al., 2022.
  • Ph.D.
    Marine, Estuary and Environ. Science Program
    U of Maryland, College Park, USA (1993)
  • M.S.
    Institute of Marine Biology
    National Sun-Yat-Sen U, Taiwan (1986)
  • B.S.
    Depart. of Biology
    National Taiwan Normal U, Taiwan (1989)

  • (02) 2783-9910 ext 1271

  • fkshiah

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