CHAPTER IX 



The Nutrition and Methods of Feeding of Shore 



Organisms 



the nutrition of marine organisms in general 



In approaching the problems presented by the nutrition 

 of marine organisms it is natural that we should call to mind 

 what we know about the corresponding problems on land. 

 We are aware, for example, that all terrestrial animals, 

 whether directly herbivorous or not, depend for their 

 nourishment upon plants which, in turn, elaborate their 

 food from the carbon dioxide of the atmosphere and from 

 certain simple inorganic compounds (the ** ultimate food- 

 stuffs ") present in solution in the soil, utilising in this 

 process the energy obtained from the sunlight. For a 

 constant supply of the most essential of these materials in 

 the requisite form plants, again, are dependent upon certain 

 micro-organisms : bacteria, moulds, and yeasts, by whose 

 agency the elements composing the bodies of dead plants 

 and animals do not pass out of circulation, but are again 

 made available for life. 



So far as our present knowledge extends it would seem 

 that the food- cycle in the sea is of substantially the same 

 character as that we have outlined above. Nevertheless, 

 marine metabolism exhibits not a few special features of its 

 own, and theories are not lacking (see those of Putter below) 

 which, if proved correct, would very materially disturt? 

 any preconceptions that our knowledge of land conditions 

 may have led us to form. 



It is usual to divide the food-stuffs present in the sea 



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