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 Trichodesmium. The protocol takes into account two optical characteristics of Trichodesmium blooms–a high reflectivity due to the presence of gas vacuoles and an absorption feature at 550nm due to the accessory pigment phycoerythrin. It is suggested that the combination of these two features 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 were known to contain a variety of phytoplanktonic classes including species of diatoms, dinoflagellates and cyanobacteria. The protocol was successful in selecting the regions where Trichodesmium was reported.