Synura freshwater algae, light microscopy. Synura are usually 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, feel their surroundings and communicate with other Synura. They belong to the order Synurophyceae, which are characterised by being covered in silicate (compound made from silica) scales and spines, and have chloroplasts, which are photosynthetic organelles that use sunlight to make energy.