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f/2 medium* (Guillard and Ryther 1963)
Updated April 2007
FOUR STOCK SOLUTIONS (1-4)

OBS! For all solutions, use sterilized distilled deionized water!
1. NaNO3 stock solution

NaNO3

For 1L75.0 g

For 0.5L
37.5 g

2. NaH2PO4 stock solution

NaH2PO4

5.0 g

2.5 g

3. Trace Metals stock solution
To distilled water add the following:
Na2EDTA
FeCl3•6H2O
(Ferric Chloride)Primary Metals Stocks (below)

For 1L
4.36 g
3.15 g
1ml of each of the five

For 0.5L
2.18 g
1.575 g
0.5ml of each of five

Primary Trace Metals stock solutions (make up five separatestocks)
To the chosen volume of sterile distilled deionized water add the following:
100ml
1.0 g
2.2 g
1.0 g
1.8 g
0.63 g

CuSO4•5H2O
ZnSO4•7H2O
CoCl2•6H2O
MnCl2•4H2O
NaMoO4•2H2O

50ml0.50 g
1.10 g
0.50 g
0.90 g
0.315g

10ml
0.10 g
0.22 g
0.10 g
0.18 g
0.063 g

4. Vitamin Stock solution
Light sensitive – keep covered in foil!
Biotin
Vitamin B12
Thiamine HCl

For1.0 L
10.0 mL of 0.1 mg•mL-1 solution (1mg in 10ml)
1.0 mL of 1.0 mg•mL-1 solution (1mg in 1ml)
0.2g

For 0.5L
5.0 mL
0.5 mL
0.1 g

Lastly: Making Final Medium
To 950 mL of 0.22 μM filteredseawater (FSW) add:
NaNO3 Stock solution
NaH2PO4 Stock Solution
Trace Metals Stock Solution
Vitamin Stock Solution

1.0 mL
1.0 mL
1.0 mL
0.5 mL

To make 100 tubes:
100 ml
100 ml
100 ml50 ml

Filter sterilize at 0.22 μM before use and store at 4° C. * Si has been removed from this recipe to
reduce the growth of contaminating diatoms.
Tip: Make up a larger batch, just multiplyeach stock by how many tubes you want to set up. For
example, for 100 tubes of 3.5ml total of f/2 final medium stock, add 100ml of each of the first
three stocks and 50 ml of the Vitamin stock. Thatgives a total of 350 ml, which gives 100 15ml
falcon tubes of 3.5 ml each of f/2 final medium stock, each of which is ready to make up one
each of 1.0L working f/2 media (one tube of 3.5 ml plus...