This algae is composed of four cells but can have up to eight in some cases. This photograph was taken with phase contrast at a magnification of X400. The above two photographs are of the cyanobacterium called Gomphosphaeria which is quite common in most localities. This cyanobacterium completely covered a small section of the perch pond on Wanstead flats to a depth of a few millimetres,colouring the surface of the water a dark green. The cells are embedded in mucilage, which also contains tubes that are connected to the cells.
Reproduction is by fragmentation and also cell division.
The dark area that surrounds each colony appears to be made up of masses of bacteria, why they congregate in this area is unclear,possibly to use the oxygen that the blue green makes. This alga was taken with a X50 Leitz water immersion lens and is probably a species called scenedesmus obliqnus which is quite common in the plankton of lakes and small bodies of freshwater. The large round body in the centre is a pyrenoid. In this photograph the mucilage can be seen surround the cell colony. This is a photograph of a species of Closterium that I am hoping to identify very shortly .