Current lidar fluorosensor apparata extract species concentrations by analysing in various domains (wavelength, time, image) the target fluorescence as induced by a single exciting laser source. In marine applications, these systems have been used for remote monitoring ecological equilibria over large areas and promptly revealing the presence of pollutants or hazardous species (DOM, oil slick, PCB etc.) as well as in the measurement of phytoplankton photosynthetic pigments owing to their relationships to the species taxonomy and to primary production. The Laser Induced Fluorescence (LIE) technique is also suitable for directly investigating the phytoplankton photosynthesis process by means of a dual laser Pump-and-Probe (PP) excitation scheme which triggers an on-off fluorescence emission by the Reaction Centers of the Photosystem II, so providing information upon the overall vegetation health status.

The ENEA mobile lidar fluorosensor equipment has been used for extensive marine campaigns to monitor the quality of different sea waters, in particular the Adriatic and North Sea. The system is operated in the LIE spectral resolved mode in a compact version which includes a custom design solid state laser transmitter (l =532nm, 355nm), capable to generate either single or couple of pump and probe pulses at the properly selected delays necessary to measure the phytoplankton photosynthetic activity. In this compact version, the send-receive optical system contains in a single frame the transmitter, the receiving optics (Cassegrain telescope and fibre optic bundle split into four or twelve branches), a set of optical filters placed at the entrances of each (4-12) PMT detectors, completed with their time gated HV electronics. The lidar apparatus is coupled to a GPS electronic equipment for georeferencing the lidar data, and to a visible solar radiance detector. Electronics controlling the experiments settings and data acquisition are based on PC and VME control systems. Laser or lamp fluorometers, recording UV-VIS fluorescence spectra either in the emission or excitation and synchronous mode, complete the set of instruments on board and are used to calibrate the lidar data on specific samples during the cruise.

The newly developed ship-borne apparatus allows for remote monitoring of the phytoplankton photosynthetic activity and to contemporary retrieval of all information on sea water parameters obtainable with a system based on a single laser transmitter. This system has already, been tested on phytoplankton during the ICES/ICC workshop (Kristineberg Marine Research Station, Sweden, 9-15 September 1996) and will participate to the next Italian Antarctic oceanographic campaign in the Ross sea (December 1997).