Upwelling of Water 



This perspective diagram (looking 

 northward in the Benguela Current) 

 shows an idealized view of the 

 principal horizontal and vertical 

 water movements that take place 

 during upwelling. The surfaces of 

 equal density, shown by the thin 

 lines on the vertical section, curve 

 upward near the edge of the conti- 

 nental shelf and rise close to the 

 surface in the coastal water. The 

 shaded wavy line running north at the 

 surface gives a rough indication of 

 the boundary between the ocean 

 surface water and the upwelled 

 coastal water. 



Organic Cycle of the Sea 



This diagram illustrates the cycle 

 of organic production in a part of 

 the sea where equilibrium conditions 

 are more or less maintained, and 

 where there are no great losses 

 to or introductions from 

 neighboring areas. Initial photo- 

 synthesis and plant growth, which is 

 consumed by herbivores (and these by 

 carnivores), build up the large 

 animals and fish. There is a lot of 

 wastage in this chain and only a 

 small part of the organic matter 

 initially produced finds its way 

 into the larger animals which we 

 catch for our food. The material 

 which is lost is returned to the 

 sea (blue spiral). 



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