Allelopathic effects in dinoflagellates: A case study of the benthic genus Ostreopsis and two non-toxic species from the genera Prorocentrum and Coolia

Abstract

The genus Ostreopsis includes several toxic species that can develop blooms in benthic ecosystems, with potential harmful consequences to the human health and marine invertebrates. Despite of this, little is known about the allelopathic effects caused by these organisms in other co-occurring microalgae. The aim of this study was to study these effects in mixed cultures of Ostreopsis and two benthic genera of dinoflagellates (Coolia and Prorocentrum), when sharing the same environment, under controlled conditions. The potential allelopathic effects were studied in two non-toxic species (Coolia monotis and Prorocentrum elegans) exposed separately to the clarified medium and cells of two strains of Ostreopsis. For this purpose, growth rates of each species, toxin profiles and toxin content per cell were determined by LC-HRMS in mixed cultures. The obtained results are discussed in terms of the interespecific differences observed in toxin contents for both Ostreopsis strains and the inhibitory effects in both Coolia and Prorocentrum cultures