JOHN H. RYTHER 409 



if all of the phosphorus were utilized and no other nutrient was limit- 

 ing. 



If the dinoflagellates in this hypothetical situation are also able to 

 utilize all the nutrients in a water column 10 meters deep, and then, 

 due to changes in their specific gravit}% accumulate in the upper 

 meter, their concentration at the surface will be in the range of 3.2 

 X 10^ cells per liter. The action of winds, convergence, or convection 

 may then easily concentrate this surface layer by another factor of 10 

 or 20, producing concentrations of organisms typical of red water con- 

 ditions, which range anywhere from 10^' to lO'^ cells per liter. 



Thus there is no necessit\' to postulate obscure factors which would 

 account for a prodigious growth of dinoflagellates to explain red 

 water. It is necessary only to have conditions favoring the growth and 

 dominance of a moderately large population of a given species, and 

 the proper hydrographic and meteorological conditions to permit the 

 accumulation of organisms at the surface and to effect their further 

 concentrations in localized areas. 



References 



Aiyar, R. G. 1936. Mortality of fish of the Madras Coast in June, 1935. 



Current Sci., 4, 488-89. 

 Allen, W. E. 1939. Phosphorescence in the sea. Naut. Gaz., Aug. 26, 1939. 

 Allen, W. E. 1946. "Red water" in La Jolla Ray in 1945. Trans. Amer. 



Microscop. Soc, 65, 149-53. 

 Barker, H. A. 1935. The culture and physiology of marine dinoflagellates. 



Arch. Mikrobiol 6, 157-81. 

 Rar\', B. M. 1953. Sea-water discoloration by living organisms. New Zealand 



J. Sci. Technol. B34, 393-407. 

 Rhimachar, B. S., and P. C. George. 1950. Abrupt set backs in the fisheries 



of the Malabar and Kanara Coasts and "red water" phenomenon as their 



probable cause. Proc. Indian Acad. Sci., B31, 339-50. 

 Bonnot, P., and J. B. Phillips. 1938. Red water, its cause and occurrences. 



Calif. Fish and Game, 24, 55-59. 

 Braarud, T. 1935. The 0st expedition to the Denmark Strait, 1929. II. The 



phytoplankton and its condition of growth. Hvalradets Shifter, Norske 



Videnskaps — Acad. Oslo, No. 10. 



