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 β,β-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 Type 5: Ochrosphaera spp.; Type 6: Nöelaerhabdaceae, 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. KEY WORDS: Haptophyta · HPLC · Chlorophylls c · Fucoxanthins · Pigment types · Phylogeny · Oceanography Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 270: [83][84][85][86][87][88][89][90][91][92][93][94][95][96][97][98][99][100][101][102] 2004 1995, Heimdal 1997), it is so time-consuming that oceanographers routinely use photosynthetic pigment profiles as chemotaxonomic markers of phytoplankton groups . In order to interpret pigment data from field samples, however, a thorough knowledge of the pigment composition of each of the likely species groups of the phytoplankton populations is necessary. Unfortunately very few wide-ranging pigment surveys of algal classes have been published, exceptions being for diatoms (Stauber & Jeffrey 1988) and haptophytes (Jeffrey & Wright 1994). Dominant species in field samples should always be assessed microscopically in representative samples (Andersen et al. 1996, Wright & van den Enden 2000.Knowledge of pigment characteristics of any group is always limited by the resolution of current separation methods. The haptophyte pigment study of Jeffrey & Wright (1994), which used the SCOR-UNESCO HPLC method of Wright et al. (1991), distinguished most of the marker carotenoids, but failed to resolve monovinyl and divinyl analogues of chlorophyll c (e.g. chlorophylls c 1 and c 2 ) and additional fucoxanthin derivatives such as 4-keto-19'-hexanoyloxyfucoxanthin (Egeland et al. 2000). Nevertheless 4 useful pigment subgroups of the class were determined. New advances in HPLC pigment technology in the past decade (Jeffrey et al. 1999 [review], Zapata et al. 2000) have allowed a new examination of the pigment composition of this important group of microalgae in the present work.The recent methods of Garrido & Zapata (1997) and Zapata et al. (2000), in which polymeric C 18 or monomeric C 8 columns were used with pyridine as solvent modifier, have allowed separation of 11 ch...

By using data collected during a continuous circumnavigation of the Southern Hemisphere, we observed clear patterns in the population-genetic structure of Prochlorococcus, the most abundant photosynthetic organism on Earth, between and within the three Southern Subtropical Gyres. The same mechanisms that were previously invoked to account for the vertical distribution of ecotypes at local scales accounted for the global (horizontal) patterns we observed. Basin-scale and seasonal variations in the structure and strength of vertical stratification provide a basis for understanding large-scale horizontal distribution in genetic and physiological traits of Prochlorococcus, and perhaps of marine microbial communities in general.