APPENDIX 



Media for the Culturing of Algae* 



1. Chu Na 10, with modified iron source. (Gerloflf, Fitzgerald and 

 Skoog) 



Grams 

 Compound per Liter 



Ca(N03)2 0.040 



K2HPO4 0.010 



MgS04.7H20 0.025 



NaaCOa 0.020 



NaaSiOg 0.025 



Ferric Citrate 0.003 



Citric Acid 0.003 



In his paper (Jour. Ecol, 30: 284-325. 1942) Chu specifies FeCls 

 as the iron source in this solution. We found ferric citrate, however, 

 to be superior to the ferric chloride. In his 1948 paper (Symbol. 

 Bot. Upsal., 10: 1-149) Rodhe reports similar results and, in addi- 

 tion, that the availability of iron is increased if an equal amount of 

 citric acid is added with the ferric citrate. We have followed 

 Rodhe's suggestion on the use of citric acid. A ferric citrate - citric 

 acid stock solution is prepared fresh each week. Although Chu was 

 primarily interested in green algae and diatom culture, we have 

 found his modified No. 10 solution suitable for the continuous 

 culture of twenty-four species of blue-green algae. 



* Submitted by authors as indicated. 



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