The detection of an algal bloom from ocean colour sensors depends on the concentration of phytoplankton pigments when pigments, such as chlorophylls, produce a significant change in the optical properties of water. The pigment composition results in a characteristic colour, which can be measured using absorption spectra and spectral reflectance signatures. An Individual phytoplankton group contains a number of accessory pigments and has its own characteristic composition. Several of these pigments are restricted to 1 or 2 phytoplankton classes. As these marker pigments have distinctive absorption spectra, which determine a characteristic spectral signature for phytoplankton, they can be used as indicators of different phytoplankton classes. Using the High Performance Liquid Chromatography (HPLC) system, major accessory pigments contained in phytoplankton samples were analysed. In situ measurements of remote sensing reflectance were obtained at wavelengths coincident with the Sea WiFS visible wavebands using a Profiling Reflectance Radiometer (PRR600, Biospherical Instruments Inc). Group specific absorption spectra were generated according to the proportion of one of the marker pigment, fucoxanthin in the sum of pigments measured by HPLC. Remote sensing reflectance was modelled based on phytoplankton group specific absorption spectra and compared to the in situ remote sensing reflectance
signatures.