Spheroid cyanobacteria have been found within the diatom Rhopalodia gibba .
Spheroid cyanobacteria have been have been found to possess genes for nitrogen fixation , but do not possess the proper pigments for photosynthesis .
Spheroid cyanobacteria have been found within the diatom Rhopalodia gibba and have been found to possess genes for nitrogen fixation , but do not possess the proper pigments for photosynthesis .