Synura. Light microscope footage of Synura freshwater algae. These organisms are usually about 30 micrometres in length and live in spherical colonies with the flagella (seen here as wiggling protrusions) pointing outwards. They use the flagella to move, sense their surroundings and communicate with other Synura. They belong to the order Synurophyceae, members of which are characterised by having coats of silicate scales and spines, and chloroplasts, which are photosynthetic organelles that use sunlight to make energy.