Ecology of Autotrophic 



Marine Dinoflagellates with Reference 

 to Red Water Conditions* 



John H. Ryther 

 Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 



Although dinoflagellate luminescence was at one time believed to be 

 restricted to a few highly specialized forms (i.e., Noctihtca, Pyro- 

 cijstis), as early as 1830 Michaelis described 9 luminous species of 

 the common genera Ceratium, Peridinium, and Prorocentrum. Kofoid 

 and Swezy ( 1921 ) attribute this property to "many if not most of the 

 Perindiniales and Gymnodiniales." The extent to which biolumines- 

 cence occurs in the group as a whole has not been systematically 

 investigated, but the opinion now appears to be widespread among 

 workers in the field that most dinoflagellates, at least under certain 

 conditions, exhibit luminescence. Kofoid, in a personal communica- 

 tion to Harvey (1952), went so far as to suggest that perhaps all 

 dinoflagellates have this property. 



The dinoflagellates are found in all the oceans of the world and 

 at least a few are usually present at every time of the year. Among 

 all forms of marine life, they are probably second in abundance only 

 to the diatoms and, in many cases, may greatly outnumber them. 

 Together with the diatoms they constitute the bulk of the so-called 

 phytoplankton, the community of unicellular, autotrophic organisms 

 that are the basis for all life in the sea. 



In view of the widespread occurrence of dinoflagellates in the 

 ocean and the apparent preponderance of luminous forms, this group 

 must be considered as one of the principal producers of biolumines- 



" Contribution No. 712 from the Woods Hole Oceanographic Institution. 



387 



