Identification of algal pigments using high order derivatives

The absorption spectra of taxonomic groups of phytoplankton have different characteristics depending on their pigment assemblages. However, the influence of these pigments on the spectra is not evident due to the overlapping of their spectral shape. The aim of this paper is to show the potential of high order derivatives in resolving the absorption peaks of the component pigments present in different algal groups. Theoretical spectral curves were generated for diatoms and green algae by summing the spectral curves for the dominant pigments, in the correct proportions. These were compared to the spectrophotometrically measured absorption spectra of three different taxa. The peaks obtained through the derivative analysis of the spectral absorption curves of each alga are in good agreement with those reported in the literature and have a clear biological explanation.