F/2 Culture Media

F/2 Medium Stock Solutions:

Quantity per liter of Media


Stock Concentration

1.0 ml NaNO3 75.0 g/L dH2O Autoclave separately
1.0 ml NaH2PO4.H2O 5.0 g/L dH2O Autoclave separately
1.0 ml Na2SiO3.9H2O 30.0 g/L dH2O Autoclave separately
1.0 ml f/2 Trace Metal Solution (see recipe below) Filter sterilize
0.5 ml f/2 Vitamin Solution (see recipe below) Filter sterilize

For each stock solution, add 1/1000 of the total culture volume. Autoclave separately aliquots of the nitrate, phosphate, and silicate solutions. Do not autoclave the trace metals or vitamin solution – these should be filter sterilized (Nalgene 50mm filter unit). Autoclave your media (filtered natural seawater). Add all the f/2 components aseptically to your media once it has cooled to room temperature. Note: f/2 medium contains extensive silica precipitate and should be used only when growing diatoms. For other algal groups (e.g. dinoflagellates, coccolithophores) use f/2-Si medium (prepare as for f/2 medium but omit Na2SiO3.9H2O). Sterile stock solutions can be stored at room temperature. Non-sterile stocks (i.e. once opened) should be stored at 4 °C.

Trace Metal Solution

To 950 mL distilled H2O add:



Stock Solution

1.3 g FeCl3.6H2O
8.7 g Na2EDTA.2H2O
1.0 ml CuSO4.5H2O 980 mg / 100 ml dH20
1.0 ml Na2MoO4.2H2O 630 mg / 100 ml dH20
1.0 ml ZnSO4.7H2O 2.2 g / 100 ml dH20
1.0 ml CoCl2.6H2O 1.0 g / 100 ml dH20
1.0 ml MnCl2.4H2O 18.0 g / 100 ml dH20

Solution will initially be cloudy. Add 1N NaOH to adjust pH to about 4.5; solution should clear unless too much NaOH has been added. Bring final volume to one liter.

Vitamin Solution

To 950 mL dH2O add:



1o Stock Solution


1.0 ml Vitamin B12 10 mg / 10 ml dH2O
1.0 ml Biotin 10 mg / 10 ml dH2O Dissolve in a little 0.1N NaOH first
200.0 mg Thiamine HCl

Make final volume up to 1.0 L with dH2O. Store primary stock solutions in freezer. Store completed vitamin solution in the refrigerator or freeze small aliquots.



Guillard R.R.L. and Ryther J.H. (1962) Studies of marine planktonic diatoms. I. Cyclotella nana Hustedt and Detonula confervacea Cleve. Can. J. Microbiol. 8: 229-239.

Guillard R.R.L. (1975) Culture of phytoplankton for feeding marine invertebrates. in “Culture of Marine Invertebrate Animals.” (eds: Smith W.L. and Chanley M.H.) Plenum Press, New York, USA. pp 26-60.