Photosynthetic Pigments of the Phytoplankton of Some Coral Reef Waters1

Phytoplankton pigments in reef waters of Princess Charlotte Bay, North Queensland, Australia, were studied by spectrophotometric and chromatographic methods. The chlorophyll concentration of reef waters was extremely low: 0.1–0.35 µ g of chlorophyll (a + c ) / liter. Chlorophyll a in most samples was 1–2 times as abundant as chlorophyll c. The phytoplankton consisted mostly of pennate diatoms and coccolithophores, with only small numbers of free‐swimming dinoflagellates. This was reflected in the presence of carotenes, chlorophylls a and c, yellow xanthophylls, and fucoxanthin in each sample. The absence of dinoflagellate pigments from most samples of reef water contrasted strongly with the abundant growth of symbiotic dinoflagellates within the reef corals.