f/2 concentrate

*This formulation has been modified by R. Anderson (2005) from the original.

Reference: Guillard, R.R.L. and Ryther, J.H. (1962). Studies of marine planktonic diatoms. I. Cyclotella nana Hustedt, and Detonula confervacea (cleve) Gran. Canadian Journal of Microbiology, 8, 229–239. doi:10.1139/m62-029

Reference: Guillard, R.R.L. (1975). Culture of phytoplankton for feeding marine invertebrates. In: M.L. Smith and M.H. Chanley (Eds.), Culture of Marine Invertebrates Animals (pp. 29-60), New York, Plenum Press, doi:10.1007/978-1-4615-8714-9_3

This concentrate is used for most marine strains of algae and cyanobacteria.

Stock Substance Primary stock (g/L) Volume used to prepare 100 mL concentrate Concentrated stock (g/L) Final concentration in medium (mg/L) (adding 10 mL/L)
  Purified H2O – 55 mL – –
1. NaNO3 75 10 mL 7.5 75
2. NaH2PO4•2H2O 5 10 mL 0.5 5
3. Na2SiO3•9H2O a 30 10 mL 3 30
4. Trace metal solution See below for concentrations 10 mL See below for concentrations See below for concentrations
5. f/2 vitamin solution See below for concentrations 5 mL See below for concentrations See below for concentrations

aNOTE: Autoclaved f/2 medium may produce extensive silica precipitate. If this is the case, you may choose to delete the silicate (f/2 Stock 3) when it is not required by the algae. Algae classes that typically require the silicate include Bacillariophyceae (diatoms), Cryptophyceae, Chrysophyceae, Dinophyceae, and Synurophyceae..

Trace metal solution

Substock Substance Primary stock (g/L) Concentrates stock (g/L) Final concentration in medium (mg/L)
1. FeCl3•6H2O 3.15 0.315 3.15
2. Na2EDTA•2H2O 4.36 0.436 4.36
3. CuSO4•5H2O 0.0098 0.00098 0.0098
4. Na2MoO4•2H2O 0.0063 0.00063 0.0063
5. ZnSO4•7H2O 0.022 0.0022 0.022
6. CoCl2•6H2O 0.01 0.001 0.01
7. MnCl2•4H2O 0.180 0.0180 0.180

f/2 vitamin solution

Substock Substance Primary stock (g/L) Concentrated stock (g/L) Final concentration in medium (mg/L)
1. Vitamin B12 (Cyanocobalamin) 0.001 0.00011 0.001
2. Biotin 0.001 0.00011 0.001
3. Thiamine 0.200 0.022 0.200

The concentrate is prepared by adding stock solutions 1-5 to 55 mL purified H2O, in the order listed above, to make 100 mL total volume. This volume will then prepare 10L of f/2 medium. Concentrate should be stored in the fridge in the dark until needed.

To prepare medium:

The final concentrations shown above are to prepare a 100% f/2 medium by adding 10 mL of concentrate to 990 mL of artificial saltwater (e.g., Instant Ocean or ESAW Salt Solutions I and II) or filtered seawater. Stir, pH adjust to 8.0 if necessary with 1N HCl or 1N NaOH. If sterile medium is needed, then the final medium may be filter-sterilized through a 0.22 um filter and dispensed aseptically into sterile vessels or autoclaved directly in the vessels. (NOTE: If you experience excessive precipitation when using artificial saltwater, you may choose to add 0.12 g/L of NaHCO3 and 1.44 mL/L of 1N HCl after adjusting the pH to 8.0 and before autoclaving.) Prepared medium should be stored in the fridge in the dark until needed.