24 THE ROLE OF ALGAE AND PLANKTON IN MEDICINE 



In 1939, too, George L. Clarke, 2 of the Woods Hole Oceanographic 

 Institute, wrote in Science that he had heard the Germans in Heligoland 

 were studying the use of plankton as a food supplement ; he said they con- 

 sidered zooplankton nutritionally equivalent to the best meat, and phy- 

 toplankton to rye flour. Clarke hypothesized that if all the organic matter 

 in marine zooplankton were assimilable, it might yield four calories per 

 gram. Thus 750 gm. plankton would be required to produce the 3000 

 calories needed daily to support a man. If, as he figured, one cubic meter 

 of water yields only 0.1 gm. dry plankton, then 7500 cubic meters of sea 

 water would have to be filtered to provide daily sustenance. This repre- 

 sents a heroic operation, but Clarke suggested using nets in the tidal flows 

 of estuarial or interinsular waters. 



The war situation spurred further interest. In 1940, W. A. Jaschnov 165 

 spoke in Russia of the desirability and the feasibility of using planktonic 

 foods. His opinion was not based on theory alone. Between 1921 and 

 1937 he had studied the distribution and concentration of zooplankton in 

 the Barents, White, Kara, Laptev, East Siberian and Chukotsk Seas, as 

 well as in the adjacent polar areas. He examined 2500 samples and made 

 1300 quantitative determinations. From these he concluded that zoo- 

 plankton contained over 90 per cent copepods, and that Calanus fin- 

 marcbicus made up about 95 per cent of the latter. Like others, Jaschnov 

 also found the highest concentration of zooplankton in the autumn. He 

 calculated that there was an average of 65 tons of Calanus available an- 

 nually per square kilometer of sea surface, equivalent to a biomass of 43 

 tons. The total biomass available yearly from the northern seas of the 

 USSR was estimated to surpass 50 million tons — 40 million tons from the 

 Barents Sea, 5 million from the Kara Sea, 3 million from the Laptev Sea, 

 2 million from the East Siberian Sea, 1 million from the Chukotsk Sea, 

 and one-half million from the White Sea. Berutski 166 also noted seasonal 

 variations of copepods in the White Lake in Russia. Wiborg 167 classified 

 many of the copepods in the Oslo fiord. 



In 1941 Sir John G. Kerr suggested in the House of Commons and 

 in the London Times that marine plankton be investigated as a food 

 source. 168 Indeed, soon thereafter, Professor A. C. Hardy 3 enthusiastically 

 urged in Nature that Clarke's tidal flow nitrations be tried in the plankton- 

 rich sea lochs of western Scotland. In the following year, Hardy 169 also 

 suggested freshwater plankton as a source of food. In 1493, Judy 4 re- 

 ported in Science on the good aquatic food potentialities of Wisconsin 

 lakes. That these war-inspired enthusiasms might be practical was further 



