Using fluorescence spectra to distingwish between microalgae species

Spectral characteristics based on in-vivo fluorescence measurements were taken of five laboratory uni-algal cultures: Isochrysis galbana, Nannochloris atomus, Tetraselmis chui, Tetraselmis pseuicia and Tetraselmis suecica. Two different techniques for fluorescence measurements have been used for detection of fluorescence of marine algae. The techniques used were Confocal Microscope LSM 510 and LabRam 1B Spectroscopic Microscope. Both instruments were able to detect the in vivo fluorescence signal of all uni-algal cultures. Different excitation wavelengths have been used. The excitation wavelength of 488 nm produced the fluorescence signal with highest intensity. Confocal fluorescence microscopy shows that the samples are spectrally uniform from cell to cell. This result suggests that fluorescence measurements can be used for identification of algal species. Raman Spectroscopy is employed to identify differences in molecular structure between the samples. Chlorophyll fluorescence of different species shows a change. As fluorescence is directly linked to the physiological state of the photosynthetic system and very sensitive to stress being experienced further research in the direction of fluorescence detection of toxic algae species will be of interest.