Phytoplankton pigment analysis by HPLC and its application in algal community investigations

A high performance liquid chromatography (HPLC) system for pigment analysis of marine phytoplankton was established. The characteristic quantification limits of the major photosynthetic chlorophylls a and b were 0.29 and 0.27 ng, respectively. The reliability of this method was verified by resolving the marker pigments in culture extracts from diatoms, blue-green algae and green algae. Fucoxanthin, zeaxanthin and chlorophyll b were selected for calculating the chlorophyll a/marker pigment ratios for the three types of algae, which were 1.39, 0.51 and 1.01, respectively. The composition of the phytoplankton community in summer samples, collected from the continental shelf of the East China Sea, was estimated by simple regression of these ratios. When results of composition abundance of diatoms and blue-green algae obtained by this method were compared with those obtained by the microscopic technique, the relative percentage difference was less than 6% for diatoms. On the other hand, a lower abundance of blue-green algae was estimated by the HPLC method.