SPECTRAL FLUORESCENCE SIGNATURES IN THE CHARACTERIZATION OF PHYTOPLANKTON COMMUNITY COMPOSITION

Fluorescence spectral signatures from 28 algal cultures are described. The cultures are split into four groups according to their accessory pigments. Phycocyanin and phycoerythrin, character istic pigments of c yanobacteria, form groups I and II. The characteristic pigment found i n group III is chlorophyll b (green and prasinophyte algae) and in gro up IV it is chlorophyll c (diatoms, dinophytes and some other algae). This preliminary catalogue of spectral signatures was used to characte rize five natural phytoplankton communities from brackish water enviro nments as a comparison with phytoplankton species found in the samples . Accessory pigments such as phycocyanin and phycoerythrin, characteri zing groups I and II, can be used for identification without confusion . Distinguishing between groups III and IV is more complicated, becaus e their accessory pigments do. not have their own fluorescence. These groups can be characterized by increased fluorescence of chlorophyll a induced by energy excited through chlorophyll b and c. The possibilit ies of applying the spectral fluorescence signatures approach to the c haracterization of natural phytoplankton communities are discussed.