f/2 Media
F/2 Nutrient Solution
This is a common and widely used general enriched seawater medium designed for growing coastal marine algae, especially diatoms. The concentration of the original formulation, termed "f Medium" (Guillard and Ryther 1962), has been reduced by half. To prepare, begin with 950 mL of filtered natural seawater and add the following components. The trace element and vitamin solutions are provided below. Bring the final volume to 1 liter with filtered natural seawater. If the alga to be grown does not require silica, then it is recommended that the silica be omitted because it enhances precipitation. Autoclave.
Table 1: f/2 Stock Solution Chemical Composition
| Components | Stock Solution | Quantity | Molar Concentration in Final Medium |
| NaNO3 | 75 g/L dH2O | 1 mL | 8.82 x10-4M |
| NaH2PO4 H2O | 5 g/L dH2O | 1 mL | 3.62 x 10-5 M |
| Na2CO3 | 30 g/L dH2O | 1 mL | 1.06 x 10-4 M |
| Trace Metal Solution | See table 2 | 1 mL | --- |
| Vitamin Solution | See Table 3 | 0.5 mL | --- |
f/2 Trace Metal Solution
To prepare, begin with 950 mL of dH2O, add the components and bring final volume to 1 liter with dH2O. Autoclave. Note that the original medium (Guillard and Ryther 1962) used ferric sequestrene; we have substituted Na2EDTA · 2H2O and FeCl3 · 6 H2O
Table 2: Trace Metal Composition
| Components | Stock Solution | Quantity | Molar Concentration in Final Medium |
| FeCl3 6(H2O) | --- | 3.15 g | 1.17 x10-5M |
| Na2(EDTA)2(H2O) | --- | 4.36 g | 1.17 x10-5M |
| CuSO4 5(H2O) | 9.8 g/L dH2O | 1 mL | 3.93x10-8 M |
| Na2MoO4 2(H2O) | 6.3 g/L dH2O | 1 mL | 2.60 x10-8 M |
| ZnSO4 7(H2O) |
22.0 g/L dH2O |
1 mL | 7.65 x10-8 M |
| CoCl2 6(H2O) | 10.0 g/L dH2O | 1 mL |
4.20 x10-8 M |
| MnCl2 4(H2O) | 180.0 g/L dH2O | 1 mL | 9.10 x10-7 M |
f/2 Vitamin Solution
First, prepare primary stock solutions. To prepare final vitamin solution, begin with 950 mL of dH2O, dissolve the thiamine, add the amounts of the primary stocks as indicated in the quantity column below, and bring final volume to 1 liter with dH2O. We autoclave to sterilize. Store in refrigerator or freezer.
Table 3: Vitamin Composition
| Components | Stock Solution | Quantity | Molar Concentration in Final Medium |
|
thiamine HCl (vitamin B1) |
--- | 200 mg | 2.96 x10-7 M |
|
Biotin (Vitamin H) |
0.1 g/L dH2O | 10 mL | 2.05 x10-9 M |
|
Cyanocobalamin (Vitamin B12) |
1 g/L dH2O | 1 mL | 3.69 x10-10 M |
Citations
Guillard, R.R.L. 1975. Culture of phytoplankton for feeding marine invertebrates. pp 26- 60. In Smith W.L. and Chanley M.H (Eds.) Culture of Marine Invertebrate Animals. Plenum Press, New York, USA.
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.