Marked differences in fatty acid profiles of some planktonic and benthic marine dinoflagellates from Malaysian waters

This study was carried out to characterize the fatty acid profiles of some planktonic and benthic marine dinoflagellates from Malaysian waters. Clonal batch cultures of Alexandrium affine, A. leei, A. minutm, A. tamarense, A. tamiyaranichii, Coolia monotis, Prorocentrum emarginatum, P. mexicanum, Ostreopsis ovata and Amphidinium sp. were harvested at late exponential phase, and total lipid was extracted. Samples were derivatized to produce fatty acid methyl esters (FAMEs). FAMEs were analyzed on a gas chromatograph with flame ionization detection. The total number of fatty acids detected in the clones ranged from 10 in the A. tamarense AtPA04 clone to 22 in the C. monotis CmPLO1 clone. Fatty acids found in all clones were myristic acid (14 : 0), palmitic acid (16 : 0), stearic acid (18 : 0), linoleic acid (18 : 2 omega 6c) and oleic acid (18 : 1 omega 9c). In all clones only a few fatty acids were dominant. In the Alexandrium clones the dominant fatty acids were 16 0, 18 : 0, cis-13,16-docosadienoic acid (22 : 2), 18 : 2 omega 6c and 18 : 1 omega 9c. There was almost complete absence of omega-3 polyunsaturated fatty acids (PUFA) in the Alexandrium clones. In the benthic species the major fatty acids were 16 : 0, eicosapentaenoic acid (EPA, 20 : 5 omega 3), docosahexaenoic acid (22 : 6 omega 3), 18 : 2 omega 6c and 18 : 1 omega 9c. In the Prorocentrum clones the major fatty acids were 14 : 0, 16 : 0, palmitoleic acid (16 : 1) and EPA. Total PUFA content in the benthic species were 37%-56%, while in the planktonic species the content was 19%-44%. The fatty acid profiles could not differentiate between species. However, cluster analysis and principal components analysis were able to clearly discriminate between the Alexandrium group, Prorocentrum group and benthic species group.