Laser induced fluorescenze technique for sea water monitoring allows no-time consuming, non-invasive and non-destructive controls. In this study, the performance of the new shipboard laser spectrofluorometric CAS-PER (Compact and Advanced Laser Spectrometer –ENEA Patent) for monitoring phytoplankton community composition was examined. The prototype CASPER is based on double laser excitation of water samples in the UV (266 nm) and visible (405 nm) spectral region and a double water filtration in order to detect both quantitative data, such as choromophoric dissolved organic matter (CDOM), proteins-like components (tyrosine, tryptophan), algal pigments (chlorophylls a and b, phycoerythrin, phycocyanin, different pigments of the carotenoid groups) and qualitative data on the presence of hydrocarbons and oil pollutants. Sea water samples from different depths have been collected and analyzed from August 2010 through November 2011 in the Gulf of Asinara (N-W Sardinia). Several sampling stations were selected as sites with different degree of pollution. The accuracy and the reliability of data obtained by CASPER have been evaluated comparing the results with other standard measurements such as: Chlorophyll a (Chl a) data obtained by spectrophotometric method and total phytoplankton abundance in terms of density and class composition. Spectral deconvolution technique was developed and integrated with CASPER system to assess and characterize a marker pigments and organic compounds in situ and in vivo. Field studies confirmed CASPER system capability to effectively discriminate characteritistic spectra of fluorescent water constituents, contributing to decrease the time-consuming manual analysis of the water samples in the laboratory
