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

2X Soil+Seawater Medium

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2X Soil+Seawater Medium

For marine algae that require salinities at 60 ppt. Add 1 L of Supplemented Pasteurized Seawater divided into 200 mL volumes and combined with soil in preparation for pasteurizing with steam.


For 200 mL Total

  1. Combine all components.
  2. Cover the medium container and steam for 2 consecutive days, 3 hours on each day. Pasteurization is a gradual rising of temperature to approximately 95 °C in 15 minutes. Then increased just over 98 °C for the 3 hour duration. Cooling occurs gradually at room temperature.
  3. Refrigerate 24 hours or more and bring to room temperature before use.

# Component Amount Stock Solution Concentration Final Concentration
1 Green House Soil 5 mL/200 mL of Supplemented Seawater
2 CaCO3
(Fisher C 64)
1 mg/200 mL of Supplemented Seawater 0.05 mM
3 Supplemented Seawater 200 mL

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.