Design and application of a lidar fluorosensor system for remote monitoring of phytoplankton

Abstract

A characterization of different phytoplankton cultures has been carried out in the laboratory in combination with laser-induced fluorescence (LIF) measurements aimed at investigating the possibility of remote monitoring by means of lidar fluorosensor systems. Cultures of microalgae characterized by different pigment contents were analysed in the visible region on near UV laser excitation. The measured spectra allowed us to obtain a fingerprint of each species and to identify the emission wavelengths in relation to the main pigment contents. The remote-sensing apparatus was upgraded with a double-pulse laser source to test the effectiveness of a LIF technique based on a pump-and-probe laser excitation scheme suitable for directly measuring the algal quantum yield. In combination with photosynthetic active radiation, the electron transport rate of the investigated phytoplankton was obtained directly in the sea water. The instrumentation for local and remote analysis of phytoplankton was applied at the ICES/IOC workshop at the Kristineberg Marine Research Station (Sweden, 9–15 September 1996), where the LIF emission of natural communities and cultures has been monitored in vivo obtaining information on the algae species present and on their photosynthetic activity.