Bacillariales

Bacillaria. Colony observed in sandy and muddy marine sediments in the vicinity of Broome, Western Australia in September 2003.  This work was supported by the Australian Biological Resources Study.

Cylindrotheca is a elongate pennate diatom is very common in sediments - the form apparently allowing the cell to penetrate through the pores of the sediments. Pennate diatoms are important in intertidal and illuminated subtidal sediments in marine ecosystems and primary producers. Pennate diatoms are capable of movement, relying on the raphe to produce thrust. Pennate diatoms are usually regarded as boat shaped, although some of the boats have very odd shapes. They can usually glide. Although enclosed in a siliceous shell, the shell of these rather delicate diatoms is flexible. The plastids contain chlorophylls a and c which gives the yellowy-brown colour. Phase contrast.

Cylindrotheca is a elongate pennate diatom usually found in sediments. Pennate diatoms are important in intertidal and illuminated subtidal sediments in marine ecosystems and primary producers. Pennate diatoms are capable of movement, relying on the raphe to produce thrust. Movement is needed so that diatoms can move towards the light, recover their location after disturbances by overlying water currents, wave actions, animal burial and so on. Several species illustrated to right. All have a siliceous shell (frustule) and chlorophyll a/c rich plastids. Phase contrast.

Cylindrotheca. Cell observed in sandy and muddy marine sediments in the vicinity of Broome, Western Australia in September 2003. This image was taken using phase contrast optics.   This work was supported by the Australian Biological Resources Study.

Cylindrotheca (sill-inn-dro-thee-ka) fusiformis, an elongate and slightly twisted pennate diatom (stramenopile), tends to move in a spiral motion, frustule not heavily silicifed and and can be deformed. Differential interference microscopy. data on this strain.