THE BALTIC SEA 



285 



««^'QUARKEN 0л4Ш 

 ?,, SEA . tj ^T 



BALTIC. • ; >-..SE A 



Fig. 129. Range of near-bottom salinity (% ) in the Gulf of 



Finland (Sagerstrale). The populated points at Twerminn 



(T) and Pelling (P) are marked on the chart. 



Fig. 130. Hydrological cross section from the Neva 



Guba westwards to the south from KotUn Island 



(Derjugin). Chlorine content in mg/1. is shown by the 



numerals. 



Distribution of nutrient salts 



We have not yet got a sufficiently full picture of the distribution of nitrogen 

 and phosphorus compounds in the Baltic (Fig. 131). The conditions of the 

 northern and eastern parts of the Sea and some points of the most western 

 part of it (Kiel Bay) have been best investigated. The amount of ammonia 

 varies from to 50 mg/m 3 . Its content is somewhat higher in surface waters 



Fig. 131. Mean content of ammonium (/), nitrates (II) and phos- 

 phates (///) in the Baltic Sea. Numerator corresponds to their 

 content in the surface layer, denominator in the depth. The 

 natural regions are divided by lines (Buch). 



