UTEX sells 2X Erdschreiber's Medium at 1X concentration only. Stock solutions and individual components for this specific medium are currently not available for purchase.

2X Erdschreiber's Medium

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2X Erdschreiber's Medium

Erdschreiber's Medium made with Supplemented Seawater instead of Pasteurized Seawater.


For 3 L Total

  1. To 3 L of pasteurized supplemented seawater (60 ppt) aseptically add each of the sterile components in the order specified.
  2. Vigorously swirl the contents of the flask to mix thoroughly.
  3. Store at refrigerator temperature.

# Component Amount Stock Solution Concentration Final Concentration
1 Supplemented Seawater 3 L
2 P-IV Metal Solution 36 mL/3 L
3 NaNO3
(Fisher BP360-500)
10 mL/3 L 0.7 M 2.3 mM
4 Na2HPO47H2O
(Sigma S-9390)
10 mL/3 L 0.02 M 0.067 mM
5 Soilwater: GR+ Medium 150 mL/3 L
6 Vitamin B12 3 mL/3 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.