36 ( ' A K ( i L I N E liEKGAARD. 



of 80 mètres. The salinity was increasing from the surface (5,97 "/ou) towards deep 

 water and reached the amount of 9,47 °/ 00 in the deptli of 80 mètres. 



The oxygen-tension is noted from the depths of mètres (102 %)> 20 mètres 

 (100,3 %), 50 mètres (94,5 %) and 98 mètres (33,5 n / ). 



Tins station is quite similar to the previous one with regards to the distribution of 

 the plankton. We have the same species dominating, viz: 



Achnanthes taeniata 

 Tlialassiosira baltica 

 Gonyaulax catenata 

 Mesodinium rubrum. 



Achnanthes taeniata was here passing över to the resting-stage. It appears to have 

 developed further here than at station F 50, the maximum of the resting-spores having 

 sunk to the depth of 40 mètres. 



STATION F 74 



In comparison with the previously mentioned stations in the Grulf of Finland we 

 find this station pooi'er concerning the plankton than those lying more to the east. This 

 station is the most „oceanic" one of the whole area, It shows the highest température, 

 the highest salinity and lias prohably the smallest amount of nutritive substances. The 

 relatively high températures indicate, that this station lias been less affected by the 

 thawed water than the others. 



The température varied in the same way as at the other stations, it amounted to 

 3,50° at the surface, to 1,88° at the depth of 50 mètres and to 2,12° at the depth of 

 60 mètres. The salinity was increasing from 6,82 n /oo (° mètres) to 7,23 u /oo ( 6Ü 

 mètres). The oxygen-tension was high too, 102 ü /o in tlie depth of mètres, 102,1 % 

 in the depth of 20 mètres and 98,9 % in tne de Pth of 50 mètres. 



The high oxygen-tension in the deep water indicates, that the water has been better 

 mixed here than in the Gulf of Finland, the oxygen-tension of the deeper layers being 

 very low there. 



The most common species were following: 



Achnanthes taeniata with resting-spores. 

 Thalassiosira baltica 

 Gonyaulax catenata 

 Lohnianniella stellaris 

 Mesodinium rubrum. 



At this station Radiosperma corbiferum occurred with its maximum nuniber, viz: 

 200 cells pr. litre. 



The maximum numbers of most of the species worth mentioning were lying in the 

 depths of 20 — 30 mètres. This fact must he regarded as a secondary circumstance as 



Tom. XLVIII. 



