AME 51:275-284 (2008)  -  DOI: https://doi.org/10.3354/ame01195

Algal bioactive compounds reduce net oxygen fluxes of artificial diatom biofilms

J. Leflaive1, E. Buffan-Dubau2, L. Ten-Hage1,*

1Laboratoire d’Ecologie Fonctionnelle (EcoLab), UMR 5245 CNRS/UPS/INPT, Université Paul Sabatier, bât 4R3, 118 route de Narbonne, 31062 Toulouse Cedex 09, France
2Laboratoire d’Ecologie Fonctionnelle (EcoLab), UMR 5245 CNRS/UPS/INPT, Université Paul Sabatier, 29 rue Jeanne Marvig, 31055 Toulouse Cedex 04, France
*Corresponding author. Email:

ABSTRACT: A wide range of chemicals are exuded by microalgae or released by grazed cells. In biofilms, these bioactive compounds may potentially exert a large effect on growing cells, since the cellular density is high and intercellular distances are short. We studied whether such compounds affect the functioning of the biofilm and, therefore, we tested several compounds. These included eicosapentaenoic acid (EPA) and 2E,4E-decadienal (DD), which are produced during grazing on diatoms. In addition, we obtained a mixture of compounds by methanolic extraction of the allelopathic green alga Uronema confervicolum. We studied how the net oxygen production rates of an artificial diatom biofilm were affected by the different compounds. The extracts of U. confervicolum significantly reduced these rates. Unexpectedly, EPA had a strong effect on the oxygen production rates in the biofilm. A toxic effect was also observed in ecotoxicological assays with the diatom Nitzschia palea. However, the inhibitory effect of DD on the biofilm was weaker than that of EPA, while DD was shown to be more toxic in liquid culture. This differential effect on liquid culture and biofilms indicates that the organization of benthic algae in biofilm should be considered when studying chemical interactions between these organisms.


KEY WORDS: Diatom biofilms · Eicosapentaenoic acid · Decadienal · Allelopathy · Oxygen microprofile · Microelectrode · Nitzschia palea


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Cite this article as: Leflaive J, Buffan-Dubau E, Ten-Hage L (2008) Algal bioactive compounds reduce net oxygen fluxes of artificial diatom biofilms. Aquat Microb Ecol 51:275-284. https://doi.org/10.3354/ame01195

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