Toxicity tests in eight species of Chrysochromulina (Haptophyta)

Abstract

Blooms of the marine flagellate Chrysochromulina have resulted in mortality of marine organisms in Scandinavian waters, including fish in aquaculture. Eight species of Chrysochromulina, namely C. apheles, C. brevifilum, C. ericina, C. hirta, C. leadbeateri, C. parva, C. polylepis, and C. simplex, isolated into unialgal culture, were examined for haemolytic activity and toxicity to the brine shrimp, Artemia salina. Haemolytic fractions were obtained from all species, but only C. polylepis cells were toxic to Artemia. Thin-layer chromatography (TLC) analysis in chloroform –methanol–water (75:25:4) and in chloroform–methanol (9:1) yielded up to six haemolytic spots. Except for one spot, these all occurred in extracts of the species examined, including Isochrysis sp., which was used as a control, C. polylepis, and the well-known fish killer Prymnesium parvum. The single unique haemolytic spot (Rf values 0.45 and 0.16 in solvents I and II, respectively) occurred in the extract from C. polylepis. When isolated by TLC, the contents of the single spot were toxic to Artemia. Key words: Chrysochromulina, toxicity, haemolytic, Artemia, thin-layer chromatography (TLC).