Diatom. Coloured scanning electron micrograph (SEM) of the wall of the diatom Thalassiosira sp.. Thalassiosira is an ocean diatom that is a major participant in the biological pumping of carbon to ocean depths and that has potential for mitigating global climate change. Diatoms are singlecelled photosynthetic algae, of which there are about 100,000 species, that have mineralised cell walls (frustules) that contain silica and provide protection and support.
