Lipids of cultured Phaeocystis pouchetii: Signatures for food-web, biogeochemical and environmental studies in Antarctica and the Southern ocean

• Published in: Phytochemistry (Oxford) Vol. 30; no. 10; pp. 3209 - 3214
• Main Authors: Nichols, Peter D., Skerratt, Jennifer H., Davidson, Andrew, Burton, Harry, Mcmeekin, Tom A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 1991
• Subjects: chemical constituents of plants; fatty acids; food chain; lipids; Marine; nutritive value; Phaeocystis pouchetii; phytoplankton; phytosterols; pigments; plant pigments; Prymnesiophyta; Prymnesiophyte; sterols; Antarctica; lipids; pigments; sterols; fatty acids; Phaeocystis pouchetii; Prymnesiophyte
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/0031-9422(91)83177-M

The lipid, fatty acid, sterol and pigment composition of cultured Phaeocystis pouchetii were analysed by capillary GC, GC-MS, TLC-FID and HPLC. Polar lipids were the dominant class. Significant variation occurred between strains in the amount of lipid per cell; lipid content varied from 3.5 pg/cell for the axenic spherical colony forming strain Al-3, to 8.2 pg/cell for the largely flagellate strain DE10 and 7.7 pg/cell for the benthic strain. The dominant sterol was 24-methylcholesta-5,22 E-dien-3β-ol irrespective of culture age or life stage composition. The major fatty acids for strain Al-3 were: 16:0, 18:1ω9c, 14:0 and 18:0, while profiles for strains DE10 and Al-4 contained 14:0, 16:0, 18:1ω9c and 18: 0. The essential fatty acids 20:5ω3 and 22:6ω3 were only minor or trace components, demonstrating the poor nutritional quality (with respect to fatty acids) of Phaeocystis to Antarctic grazers. However, the lipid and fatty acid content of the strains indicate that the flagellate stage is of greater nutritional value than the free floating colonies, and that the flagellate and benthic colonial stages are most biochemically alike. The major pigments in all strains were chlorophylls a and c and 19′-hexanoyloxyfucoxanthin. Minor carotenoids detected were 19′-butanoyloxyfucoxanthin, fucoxanthin, diadinoxanthin and diatoxanthin. Small variations were observed between cultures. One major difference was that zeaxanthin was the second most abundant carotenoid in the stationary phase culture of strain Al-4. It will not be possible to use any single lipid or pigment component as a signature for Phaeocystis as not surprisingly, considerable overlap occurs between profiles observed for Phaeocystis and members of other algal groups. It is highly likely, however, that the use of component ratios for selected lipids and pigments will be of considerable use in estimating a Phaeocystis contribution to environmental samples.