UTEX sells Artificial Seawater Medium at 1X concentration only. Stock solutions and individual components for this specific medium are currently not available for purchase.

Artificial Seawater Medium

View Media Recipe

View Available Downloads

Artificial Seawater Medium

Modification of Brand's ASP2 medium for 2268 Agmenellum quadruplicatum; suitable for other axenic marine cultures (salinity = 18 ppt).


For 1 L Total

  1. To approximately 850 mL of dH2O, add each of the components in the order specified (except vitamins) while stirring continuously.
  2. Adjust the pH to 8.1.
  3. Bring the total volume to 1 L with dH2O.
    • For 1.5% (w/v) agar medium: add 15 g of agar to the flask; do not mix.
  4. Cover and autoclave medium.
  5. Allow to cool and add vitamin B12.
    • For agar medium: add vitamin, mix, and dispense before agar solidifies.
  6. Store at refrigerator temperature.

# Component Amount Stock Solution Concentration Final Concentration
1 NaCl
(Fisher S271-500)
18 g/L 0.31 M
2 MgSO47H2O
(Sigma 230391)
10 mL/L 26 g/100 mL dH20 10.5 mM
3 KCl
(Fisher P 217)
10 mL/L 6 g/100 mL dH20 8 mM
4 NaNO3
(Fisher BP360-500)
10 mL/L 10 g/100 mL dH20 11.8 mM
5 CaCl22H2O
(Sigma C-3881)
10 mL/L 3 g/100 mL dH20 2 mM
6 KH2PO4
(Sigma P 0662)
10 mL/L 0.5 g/100 mL dH20 0.37 mM
7 Tricine (adjust to pH 8)
(Sigma T-5816-256)
20 mL/L 22.4 g/100 mL dH20 25 mM
8 P-II Metal Solution 10 mL/L
9 Chelated Iron Solution 1 mL/L
10 NH4Cl
(Fisher A 649-500)
1 mL/L 2.7 g/100 mL dH20 0.5 mM
11 Vitamin B12 1 mL/L

Important Notes To Consider:

  • The quality of water, including natural seawater, is important. The term 'dH2O' generally refers to distilled, deionized, distilled/deionized water, Milli-Q water (Millipore Corp.), etc. Natural seawater and natural freshwater should be obtained from a non-polluted source.
  • When dissolving chemicals, wait for the first component to dissolve before adding the second. Stirring, and sometimes the addition of heat, is often required to dissolve the chemicals efficiently. Preparation of stock solutions for frequently made algal culture media make preparing media convenient but also necessary to avoid errors from weighing very tiny amounts.
  • Attention should be given to the pH of the final medium. In most cases, if pH adjustment is required, this occurs before sterilization. Please note that autoclaving removes carbon dioxide from media lacking carbonate stabilizing buffers. This would make the medium very alkaline soon after removal from the autoclave. In these cases, you should wait approximately 24 hours for gaseous equilibrium before inoculating the medium.