Photosynthetic pigments in 37 species (65 strains) of Haptophyta:: implications for oceanography and chemotaxonomy

The pigment compositions of 37 species (65 strains) of cultured haptophytes were analysed using improved HPLC methods. We distinguished 8 pigment types based on the distribution of 9 chlorophyll c (chl c) pigments and 5 fucoxanthin derivatives. All types contained chl c(2) and Mg-2,4-divinyl phaeoporphyrin a(5) monomethyl ester (MgDVP), fucoxanthin, diadinoxanthin and beta,beta-carotene. Pigment types were based on the following additional pigments: Type 1: chl c(1); Type 2: chl c(1) and chl c(2)-Pavlova gyrans-type; Type 3: chl c(1) and chl c(2)-monogalactosyl diacylglyceride ester (chl c(2)-MGDG [18:4/14:0]); Type 4: chl c(1), chl c(3) and non-polar chl c(1)-like; Type 5: chl c(1), chl c(3), chl c(2)-MGDG [ 18:4/14: 0] and 4-keto-fucoxanthin; Type 6: chl c(3), monovinyl chl c(3) (MV-chl c(3)), chl c(2)-MGDG [18:4/14:0], 19'-hexanoyloxyfucoxanthin and its 4-keto derivative, and traces of 19'-butanoyloxyfu-coxanthin; Type 7: similar to Type 6, minus MV-chl c(3) but with chl c(2)-MGDG [14:0/14:0] added; Type 8: similar to Type 6, minus MV-chl c(3) but with significant 19'-butanoyloxyfucoxanthin. Taxonomic associations ranged from single genera to multiple families - Type 1: Pavlovaceae, Isochrysidaceae and Pleurochrysidaceae; Type 2: Pavlovaceae; Type 3: Isochrysidaceae; Type 4: Prymnesium spp.; Type 5: Ochrosphaera spp.; Type 6: Noelaerhabdaceae, notably Emiliania spp.; Type 7: Chrysochromulina spp.; Type 8: Phaeocystaceae, Prymnesiaceae and Isochrysidaceae. These pigment types showed a strong correlation with available phylogenetic trees, supporting a genetic basis for the pigment associations. The additional marker pigments offer oceanographers greater power for detecting haptophytes in mixed populations, while also distinguishing a greater proportion of them from diatoms.