Culture and Nutrition of Gynnnodinium breve 



David V. Aldrich 



During the past year this phase of red-tide work suffered the absence 

 of its project leader on a training program. 



A direct relationship between the abundance of G. breve and annual 

 rainfall in the Florida west coast area has been suggested by various workers. 

 This theory arose from comparisons between field observations of G. breve 

 and meteorological data. Subsequent studies by W, B. Wilson indicated that 

 Florida peat extract and/or river water can promote growth of G. breve. We 

 have recently compared the growth of G. breve in water from several rivers in 

 red-tide and non- red-tide areas. A completely defined artificial sea water, in- 

 capable of supporting growth by itself, was employed as a diluent for the river 

 waters. The Alafia, Hillsborough, Peace, and Ccdoosahatchee Rivers of Florida 

 and the Atchafalaya and Sabine Rivers of Louisiana and Texas were tested. 

 Growth occurred only with the addition of Hillsborough or Peace River water. 



Since some other dinoflagellates are capable of heterotrophy, the 

 possibility existed that G. breve might also exhibit this type of nutrition -- 

 the utilization of organic substances for growth in the absence of light. More 

 than 80 organic compounds and mixtures -- including soil extracts, amino acids, 

 carbohydrates, fats, and proteins -- have been tested as potential foods, but all 

 failed. 



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