PLANKTON 



45 



The palatability and acceptability of phytoplankton as a human food 

 are dependent upon many factors. These include especially appearance 

 and taste. These depend, in turn, upon whether the material is fresh or 

 dried; also, whether it is eaten as such, or mixed (and diluted) with more 

 familiar foods. Doubtless much improvement can and will be made in all 

 these respects for a greater acceptability. Certainly these items must be 

 worked out before plankton is really the "food of the future." 236 



3. Medical Aspects 



a. Water Supply and Sewage Disposal 



Despite all the hopeful reports on their merits, it must be emphasized 

 that phytoplanktonic organisms can exert adverse effects upon the waters 

 in which they flourish. These include not only changes in appearance, 

 odor, and taste of the water, but also changes in other aquatic organ- 

 isms. 237243 Even more important are the varying degrees of intoxication 

 and reaction in animals and humans who ingest or come in contact with 

 these waters. The potential economic losses are self-evident. 



Similar to the striking colorations of the seas previously mentioned 

 (e.g., Red Sea, Vermilion Sea) are the alterations in appearance of fresh 

 water bodies. "Water bloom" is present when extensive growths of micro- 

 scopic algae blanket the surface of a lake, pond, or stream. In Europe the 

 phenomenon has been variously called "Wasserbliithe," "fleur d'eau," 

 and "flos aquae"; in some North Central parts of the United States, the 

 ancestral Dutch "vasserbloom" designation is used. Under favorable cir- 

 cumstances, microscopic algae, especially the Myxophyceae, can grow so 

 rapidly that the water assumes the color of the organism. And these colors 

 are indeed variegated. The Oscillatoria and Cylindrospermium produce 

 a green slime and a bluish soup, respectively. Chlamydomonas and Pleuro- 

 coccus are a brilliant green. Ceratium hirundinella presents a rusty color 

 and a powerful stench — perhaps the basis of the Biblical story (Exodus: 

 7) of the turning of the Nile into blood and the death of the fish therein. 

 "Red water" and "red snow" in Australia are due primarily to Myxophy- 

 ceae, but desmids (Conjugata) may >je a factor. Both "red tide" and 

 "yellow tide" have been reported along the coast of the Gulf of Mexico, 

 while two major outbreaks of "red water" occurred in Gokasho Bay, Japan, 

 in 1933 and 1934, from Gymnodinium mikimotoi. 



Whereas the colorations are interesting and occasionally even weird, 

 the odors arising from aquatic algal growths are more important, both 

 esthetically and economically. They affect water supply and sewage dispo- 



