136 



DEPTHS OF THE OCEAN 



side branches 



(see 



berry - like bladders on special small 



Fig- 243)- 



One cannot help being struck by the fact that the drifting 

 Sargasso weeds are destitute of the ordinary organs of repro- 

 duction. This seems to be invariably the case with attached 

 algae that have been torn loose from their support. They con- 

 tinue to grow vegetatively, but are deprived of all power of 

 forming new reproduction organs, until they can attach them- 

 selves afresh. The same holds good, too, with those strange 



broken-off masses of 

 algae that one finds 

 drifting about along 

 the bottom in bays, the 

 constant movement of 

 the water-masses pre- 

 venting them from 

 attaching themselves 

 to the soft mud or 

 sand. 



The Sargasso 

 weed continues to 

 grow as it drifts, but 

 the gas -bladders are 

 not formed in the 

 same proportion as 

 on the ordinary 

 branches, the result 

 being that one finds 

 newly detached 

 patches close up to 

 the surface, whereas 

 the older patches with 

 a greater specific 

 weight have sunk lower down. These last have, moreover, 

 thinner branches and a lighter olive-brown colour. Finally, 

 the power of floating ceases altogether, and the patches sink 

 into deep water and perish. Their disappearance is, however, 

 quite imperceptible, since fresh patches of weed are constantly 

 arriving from the coast. 



It is quite usual to find smaller algae fastened to the Sargasso 

 weed, and there is, besides, a characteristic animal-life amidst its 

 branches, but none of these organisms properly belong to 

 the ocean, notwithstanding their being found there so invariably. 



Fig. 243. 



-Branch of Sargassum bacciferum. 

 (From Kerner.) 



