Corethron criophilum continues to be the most abundant diatom in both our station E and local aquarium water samples. The above micrograph (thank you Deneb Karentz) shows a single corethron cell (a little off to the right from dead center) a dividing cell (to the left) and vacant valves off to the right.
Diatoms have silica valves (literally glass shells) that are made of two parts, one slightly larger than the other, that fit together like a petri disk or pill capsule. The greenish spots you see within the cells are chloroplasts. Chloroplasts are where photosynthesis is carried out and light energy from the sun is converted into a form that the cell can use to carry out metabolic activities. The empty glass valves pictured are remnants leftover from dead diatom cells- RIP.