Fig 6. Sponge species hosting cyanobacteria recorded through time (A), and methods used for the investigation of cyanobacteria symbionts (B), in relation with research effort (i.e. number of publications).

LM: Light microscopy, FL: Fluorescence microscopy, TEM: Transmission electron microscopy, SEM: Scanning electron microscopy, NGS: Next generation sequencing, DGGE: Denaturing gradient gel electrophoresis, FISH: Fluorescence in situ hybridization, chl a: chlorophyll a measurements.