AN EMPIRICALLY DERIVED PROTOCOL FOR THE DETECTION OF BLOOMS OF THE MARINE CYANOBACTERIUM TRICHODESMIUM USING CZCS IMAGERY

A protocol was developed for use with Coastal Zone Color Scanner (CZCS ) imagery to detect blooms of the N2 fixing cyanobacterium Trichodesmi um. The protocol takes into account two optical characteristics of Tri chodesmium blooms-a high reflectivity due to the presence of gas vacuo les and an absorption feature at 550 nm due to the accessory pigment p hycoerythrin. It is suggested that the combination of these two featur es is unique to Trichodesmium blooms. The protocol was validated using six CZCS scenes, with sea-truth from the Atlantic, Indian and Pacific oceans. The scenes included both coastal and deep ocean regions and w ere known to contain a variety of phytoplanktonic classes including sp ecies of diatoms, dinoflagellates and cyanobacteria. The protocol was successful in selecting the regions where Trichodesmium was reported.