Marine Biology

, Volume 147, Issue 2, pp 541–549

Superoxide production by marine microalgae

II. Towards understanding ecological consequences and possible functions
  • Judith-Anne Marshall
  • Tom Ross
  • Stephen Pyecroft
  • Gustaaf Hallegraeff
Research Article

DOI: 10.1007/s00227-005-1597-6

Cite this article as:
Marshall, JA., Ross, T., Pyecroft, S. et al. Marine Biology (2005) 147: 541. doi:10.1007/s00227-005-1597-6

Abstract

This study investigated the possible roles of superoxide produced by raphidophyte and prymnesiophyte microalgae as an ichthyotoxic agent to damselfish and an allelopathic agent to bacteria. We found that the rate of superoxide production varied with algal cell density, with cell densities of the raphidophyte Chattonella marina >10,000 cells ml−1 producing less environmental levels of superoxide per cell (94±14 chemiluminescence units) than cell densities <10,000 cells ml−1 (390±54 units per cell). Microalgal cells have the capacity to change their superoxide production rate over a period of 1 h, dependent on cell density and metabolic activity. We also examined the effect of superoxide on suppression of bioluminescence of the marine bacterium Vibrio fischeri as a model for bacterial alleopathy and found that both superoxide and free fatty acids such as eicosapentaenoic acid (EPA; 20:5ω3) present in raphidophyte microalgal cells cause suppression of bacterial bioluminescence. The combination of superoxide in the presence of EPA further enhanced bioluminescence suppression. Superoxide was also found to enhance the toxicity of free fatty acid EPA to damselfish (Acanthochromis polycanthus) at concentrations as low as 0.2 mg l−1. In conclusion, consideration should be given to density dependent and/or metabolic variations of toxicity when publishing minimum alert levels for superoxide producing ichthyotoxic microalgal species. A secondary role of superoxide production may be to enhance the toxicity of algal exudates or serve as an allelopathic agent against bacterial fouling.

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Judith-Anne Marshall
    • 1
    • 4
  • Tom Ross
    • 2
  • Stephen Pyecroft
    • 3
  • Gustaaf Hallegraeff
    • 1
  1. 1.School of Plant ScienceUniversity of TasmaniaHobartAustralia
  2. 2.School of Agricultural ScienceUniversity of TasmaniaHobartAustralia
  3. 3.Department of Primary Industry, Water and EnvironmentFish Health UnitKings MeadowsAustralia
  4. 4.Phycotec Aquaculture Environmental ManagementClifton BeachAustralia

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