Short-term variations in the pigment composition of a spring phytoplankton bloom from an enclosed experimental ecosystem

Phytoplankton samples taken during the spring bloom in the experimental enclosed ecosystem bags at Loch Ewe, Scotland, during 1983 were analysed for carotenoids and chlorophyll compounds using high-performance liquidchromatography (HPLC). Changes in the relative proportions of these pigments were related to day-to-day changes in the composition of the bloom and the physiological state of the algae. There is clear evidence for a change in the chlorophyllide a:chlorophyll a ratio, which reached a maximum as nutrient limitation occurred. No major qualitative changes in the carotenoid components were seen during the bloom; the relative proportion, however, of some carotenoids does provide useful information on the relative abundance of certain algal type in the phytoplankton.