CR1 Diatom Medium
The medium is prepared on a tube by tube basis, using 15 mL glass tubes, stoppered with rubber-lined screw caps.
Directions
Add the components in the following order. Once soil and liquid are mixed, the media must be processed (pasteurized or autoclaved) within 6 hrs. For routine maintenance and transfer, autoclaved media for 15 min, since transfer material typically contains organics and/or bacteria needed for algal growth. In pasteurization, tubes are brought to just over 98 °C, and held at that temperature for 2 hrs. They are then allowed to cool to room temperature for 20-24 hrs. This process is repeated for three successive days. It is imperative that media (pasteurized or autoclaved) be allowed to gas-equilibrate for 2 days prior to use.
| # | Component | Amount | Stock Solution Concentration | Final Concentration |
|---|---|---|---|---|
| 1 | CR1 Soil | 1 cc | ||
| 2 | MgCO3 (MCIB CB486) | 0.5 mg/12 mL | 0.5 mM | |
| 3 | dH2O | 12 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.
Additional algal culture media recipes can be found at the following other major Collections' websites:
- Culture Collection of Algae and Protozoa (CCAP)
- National Center for Marine Algae and Microbiota (NCMA)
- National Institute for Environmental Studies (NIES) Microbial Culture Collection
- The Pasteur Culture Collection of Cyanobacteria (PCC)
- The Culture Collection of Algae at Goettingen University (SAG)
- Canadian Phycological Culture Centre (CPCC)
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