

The whale, the largest living animal, feeds 

 on plankton as do creatures only a small 

 fraction of its size. A blue whale in its 

 life eats about 10,000 tons of euphausians, 

 a shrimplike plankton which grows 

 to two inches in length. Called "krill" by 

 whalers, euphausians in this quantity in 

 turn require about one million tons of 

 phytoplankton. (Print of the stranded whale 

 is by the Japanese artist Kuniyoshi.) 



phytoplankton is eaten by the smallest floating animals (the zoo- 

 plankton); these in turn feed the larger animals; when the larger 

 animals die, their organic remains are broken down to phosphates 

 and nitrates by the bacteria. 



The animals of the plankton are much less numerous, though 

 more varied, than the plants. Just as a very rough estimate, you 

 might expect to find about 20,000 plants, against only 1 20 animals, 

 in a cubic foot of sea water. Something like that proportion must 

 be maintained in order to maintain the balance of life in the oceans. 

 When one of the zooplankton eats a quantity of phytoplankton 

 only 10 per cent of the material consumed is converted into flesh. 

 The rest is "lost" as waste or energy. The larger animals that feed 

 on the zooplankton also conserve only 10 per cent of their food as 

 flesh, and so on along the scale. 



The enormous number of organisms in the sea cannot be set 

 forth in figures. But to get some idea of the multitudes, consider 

 the required amount of food for one blue whale weighing about 

 100 tons. To maintain such a weight it must consume in its life- 

 time 100 times 100 tons of euphausians, its sole food. Euphausians 

 are shrimplike zooplankton up to two inches long, so the number 



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