What drives the distribution of the bloom-forming cyanobacteria Planktothrix agardhii and Cylindrospermopsis raciborskii?

Authors

  • Sylvia Bonilla,

    Corresponding author
    • Grupo de Ecología y Fisiología de Fitoplancton, Sección Limnología, Instituto de Ecología y Ciencias Ambientales, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
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  • Luis Aubriot,

    1. Grupo de Ecología y Fisiología de Fitoplancton, Sección Limnología, Instituto de Ecología y Ciencias Ambientales, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
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  • Maria Carolina S. Soares,

    1. Department of Sanitary and Environmental Engineering, Universidade Federal de Juiz de Fora Luis de Fora, Brazil
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  • Mauricio González-Piana,

    1. Grupo de Ecología y Fisiología de Fitoplancton, Sección Limnología, Instituto de Ecología y Ciencias Ambientales, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
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  • Amelia Fabre,

    1. Grupo de Ecología y Fisiología de Fitoplancton, Sección Limnología, Instituto de Ecología y Ciencias Ambientales, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
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  • Vera L.M. Huszar,

    1. Museu Nacional, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil
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  • Miquel Lürling,

    1. Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, Wageningen University, Wageningen, The Netherlands
    2. Department of Aquatic Ecology, Netherlands Institute of Ecology, Royal Netherlands Academy of Arts and Sciences, Wageningen, The Netherlands
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  • Dermot Antoniades,

    1. Grupo de Ecología y Fisiología de Fitoplancton, Sección Limnología, Instituto de Ecología y Ciencias Ambientales, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
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  • Judit Padisák,

    1. Department of Limnology, Pannon University, Veszprém, Hungary
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  • Carla Kruk

    1. Grupo de Ecología y Fisiología de Fitoplancton, Sección Limnología, Instituto de Ecología y Ciencias Ambientales, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
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Correspondence: Sylvia Bonilla, Sección Limnología, Facultad de Ciencias, Iguá 4225, 11400-Montevideo, Uruguay. Tel.: +598 25258618, ext. 7148; fax: +598 25258617; e-mail: sbon@fcien.edu.uy

Abstract

The cyanobacteria Planktothrix agardhii and Cylindrospermopsis raciborskii are bloom-forming species common in eutrophic freshwaters. These filamentous species share certain physiological traits which imply that they might flourish under similar environmental conditions. We compared the distribution of the two species in a large database (940 samples) covering different climatic regions and the Northern and Southern hemispheres, and carried out laboratory experiments to compare their morphological and physiological responses. The environmental ranges of the two species overlapped with respect to temperature, light and total phosphorus (TP); however, they responded differently to environmental gradients; C. raciborskii biovolume changed gradually while P. agardhii shifted sharply from being highly dominated to a rare component of the phytoplankton. As expected, P. agardhii dominates the phytoplankton with high TP and low light availability conditions. Contrary to predictions, C. raciborskii succeeded in all climates and at temperatures as low as 11 °C. Cylindrospermopsis raciborskii had higher phenotypic plasticity than P. agardhii in terms of pigments, individual size and growth rates. We conclude that the phenotypic plasticity of C. raciborskii could explain its ongoing expansion to temperate latitudes and suggest its future predominance under predicted climate-change scenarios.

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