278 ^ FOUNDERS OF OCEANOGRAPHY 



least the possibility that there may be much more ultimate 

 food matter in the sea than is at present made use of, and 

 that a scientific aquiculture in the future may discover the 

 means of converting more of the available carbon into fish 

 food and then into fish, so as to increase our marine harvest. 

 Testing the alkalinity of the sea-water may therefore be 

 said to be merely ascertaining and measuring the results of 

 the photosynthetic activity of the great phyto-plankton rise 

 in spring due to the daily increase of sunlight. 



It must not be supposed that in these two chapters I have 

 been able to give an exhaustive account of plankton occur- 

 rence, investigations, methods, difficulties, and results ; 

 but possibly enough has been said to give some idea of 

 the nature of the matter and its importance both in scientific 

 interest and in practical utility. I shall have to return to 

 the subject of plankton in relation to the ultimate food of 

 the sea in the final chapter. 



