Feeding by Heterotrophic Dinoflagellates and Ciliates on the Free-living Dinoflagellate Symbiodinium sp. (Clade E)

Authors

  • Hae Jin Jeong,

    Corresponding author
    1. School of Earth and Environmental Sciences, College of Natural Sciences, Seoul National University, Seoul, Korea
    • Correspondence

      H.J. Jeong, School of Earth and Environmental Sciences, College of Natural Sciences, Seoul National University, Seoul 151-747, Korea

      Telephone number: +82-2-880-6746;

      FAX number: +82-2-874-9695;

      e-mail: hjjeong@snu.ac.kr

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  • An Suk Lim,

    1. School of Earth and Environmental Sciences, College of Natural Sciences, Seoul National University, Seoul, Korea
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  • Yeong Du Yoo,

    1. School of Earth and Environmental Sciences, College of Natural Sciences, Seoul National University, Seoul, Korea
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  • Moo Joon Lee,

    1. School of Earth and Environmental Sciences, College of Natural Sciences, Seoul National University, Seoul, Korea
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  • Kyung Ha Lee,

    1. School of Earth and Environmental Sciences, College of Natural Sciences, Seoul National University, Seoul, Korea
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  • Tae Young Jang,

    1. School of Earth and Environmental Sciences, College of Natural Sciences, Seoul National University, Seoul, Korea
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  • Kitack Lee

    1. School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang, Korea
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Abstract

To investigate heterotrophic protists grazing on Symbiodinium sp., we tested whether the common heterotrophic dinoflagellates Gyrodinium dominans, Gyrodinium moestrupii, Gyrodinium spirale, Oblea rotundata, Oxyrrhis marina, and Polykrikos kofoidii and the ciliates Balanion sp. and Parastrombidinopsis sp. preyed on the free-living dinoflagellate Symbiodinium sp. (clade E). We measured the growth and ingestion rates of O. marina and G. dominans on Symbiodinium sp. as a function of prey concentration. Furthermore, we compared the results to those obtained for other algal prey species. In addition, we measured the growth and ingestion rates of other predators at single prey concentrations at which these rates of O. marina and G. dominans were saturated. All predators tested in the present study, except Balanion sp., preyed on Symbiodinium sp. The specific growth rates of O. marina and G. dominans on Symbiodinium sp. increased rapidly with increasing mean prey concentration < ca. 740–815 ng C/ml (7,400–8,150 cells/ml), but became saturated at higher concentrations. The maximum growth rates of O. marina and G. dominans on Symbiodinium sp. (0.87 and 0.61/d) were much higher than those of G. moestrupii and P. kofoidii (0.11 and 0.04/d). Symbiodinium sp. did not support positive growth of G. spirale, O. rotundata, and Parastrombidinopsis sp. However, the maximum ingestion rates of P. kofoidii and Parastrombidinopsis sp. (6.7–10.0 ng C/predator/d) were much higher than those of O. marina and G. dominans on Symbiodinium sp. (1.9–2.1 ng C/predator/d). The results of the present study suggest that Symbiodinium sp. may increase or maintain the populations of some predators.

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