Siderophilic bacteria, bacteria that require or are facilitated by free iron
Gram-negative bacteria | Gram-positive bacteria | Sulfate-reducing bacteria | Siderophilic bacteria | Shown above as a result of a 7 week period where the columns have been allowed to grow algae, cyanobacteria and other bacterial colonies. Of specific interest are the red regions of the middle column, indicative of purple non-sulfur bacteria (e.g. ''Rhodospirillaceae | gram-positive bacteria | ''E. coli'' bacteria | Coliform bacteria |