In bright light, the individual cells of Coscinodiscus granii appear golden-brown. This is because the numerous chloroplasts inside the cell, which are visible through the transparent silica test, contain orange-brown pigments for photosynthesis, rather than the more familiar green chlorophyll. Like Ethmodiscus rex, Coscinodiscus granii is disk-shaped and radially symmetrical (that is, if it is cut in half, the two halves are mirror images of each other). During replication (asexual reproduction), the two halves (valves) of the test separate so that each daughter cell inherits one valve from its parent and creates the other valve itself. In contrast, a cell that is created as a result of sexual reproduction produces both halves of its test.
- Group Diatoms
- Diameter Up to 0.1 mm
- Habitat Surface waters
- Distribution Widespread in Northern Hemisphere