THE ARAL SEA 



661 



sea-weeds go down much deeper than Zostera, and these sea-weeds (mainly 

 Vaucheria dichotoma) form a thick cover on grey mud down to depths of 

 26 m. The Charial sea-weed Tolypella aralica forms abundant beds on black 



Е2Э < '"О re« litre 



E^ 500-1300 » 



W",\ 1300-2500 ■• 



ВШ > 2500 



Fig. 312. Quantitative distribution of plankton 



in the Aral Sea in summer 1932-33, number of 



specimens per litre (Behning). 



ooze which smells of hydrogen sulphide, mainly in bays and inlets more or 

 less separated from the Sea. The thin brown film covering the mud soils 

 comprises a huge number of diatomaceous algae. 



The qualitative composition and quantitative distribution of zoobenthos (Fig. 

 313). Qualitatively zoobenthos is as poor as plankton; it comprises only 48 

 forms : 



Foraminifera 



Nematoda (free-living) 



Turbellaria 



Oligochaeta 



Bryozoa 



Harpacticoida 



Ostracoda 



2 species 

 7 species 



12 species 



3 species 

 1 species 

 5 species 

 3 species 



Amphipoda 



Gastropoda 



Lamellibranchiata 



Trichoptera 



Chironomidae 



Hydracarina 



1 species 



2 species 

 4 species 

 2 species 

 6 species 

 1 species 



