MICROALGAL PIGMENT ASSESSMENTS USING HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY - A SYNOPSIS OF ORGANISMAL AND ECOLOGICAL APPLICATIONS

Past and current efforts at identifying microalgal phylogenetic groups rely largely on microscopic evaluation, which requires a high level of taxonomic skill, may take considerable time, can be variable among personnel, and does not allow characterization of the physiological status of the taxa. High-performance liquid chromatography (HPLC) has proven effective in rapidly separating and distinguishing chlorophylls, chlorophyll-degradation products, and carotenoids within monotypic and mixed algal samples. When coupled with absorbance and/or fluorescence spectroscopy, HPLC can accurately characterize phylogenetic groups and changes in community composition and yield information concerning microalgal physiological status, production, trophic interaction, and paleolimnology/paleooceanography. The recent widespread occurrence of toxic and noxious phytoplankton blooms has necessitated the use of remote imagery of pigment and reflectance ''signatures'' for monitoring and predicting bloom distribution. Because HPLC allows the processing of large numbers of samples from numerous locations relatively quickly, it is ideally suited for large-scale ''ground truthing'' of remotely sensed imagery. Coupled with rapidly evolving computer-based remote sensing technologies, HPLC-based pigment analyses may provide accurate assessments of aquatic biogeochemical flux, primary production, trophic state, water quality, and changes therein un local, regional, and global scales.