Showing posts from January, 2016

Diatom of the month - January 2016: Gomphonema parvulum

by Luca Marazzi*

‘Who’ is it? The genus Gomphonema includes numerous species growing on mucilaginous stalks. These diatoms are asymmetrical biraphid, as the bottom part is usually longer and thinner than the top part and they have two raphes, narrow slits that allow them to move over surfaces. Yes, there are diatoms that perform photosynthesis, move and even eat organic matter! G. parvulum is on the lower end of the size spectrum for the genus (length from 15 to over 100 µm and width between 5 and 15 µm).

Gomphonema parvulum, partially    obstructed by Eunotia, in a sample from the Florida Everglades. Source: Tobias and Gaiser, 2006 G. parvulum and stalks in a sample from Japan; cell body: 48 µm long, 10 µm wide.  Source:

Where does it live? In North America, species of Gomphonema can be found in many habitat types in lakes and streams with pH close to 7. Gomphonemaparvulum is widespread and tends to live in freshwater with high nutrient concentrat…