Diatom stock culture and cell volume
Stock cultures for all diatom species, Cocconeis sublittoralis, Achnanthes longipes, Navicula cf.
jeffreyi and Delphineis sp. were grown in sterile 50 mL culture flasks with 25 mL of f/2 media
(Guillard and Ryther 1962). Diatom cell volume was determined by measuring the length and
width of 6 cells per species using an inverted microscope. The cell volume was then calculated
using the following formula