THE INTERNAL ECONOMY OF THE SEA 



abounding in the shore area in the wide sense. 

 Though many of the seaweeds have also brown or 

 red pigment, all have chlorophyll. And by virtue 

 of this we do not know how they are able to 

 utilize the energy of the sunlight to build up the 

 simple constituents of air and sea-water into complex 

 organic products which in turn form the food of 

 animals. On this power of photosynthesis depends 

 the whole economy of marine and of terrestrial life. 

 It is very generally believed that the chief producers 

 are the minute and simple Algae of the open waters, 

 which form in certain areas what Sir John Murray 

 used to call "floating meadows." On the Beagle 

 voyage Darwin was impressed off the coast of South 

 America with vast tracts of water discoloured by 

 the minute floating Algse, the " sea-sawdust " of 

 Captain Cook's sailors, and since the days of the 

 Challenger information in regard to the minute 

 surface plants has grown apace. They seem to be 

 the food of many open-sea animals, such as small 

 Crustaceans, which again are devoured by young 

 fishes. The growth of the sea-meadows in spring 

 is thus as important as the garment of green on the 

 farmer's fields. Professor Herdman, of Liverpool, 

 a leading authority on the biology of the sea, cites 

 the calculation that a Diatom " less than the head 

 of a pin, dividing into two at the normal rate of 

 five times in the day, would at the end of a month 

 form a mass of living matter a million times as big 

 as the sun. The destruction that keeps such a rate 

 of reproduction in check must be equally astonish- 

 ing." 



51 



