32 



Caroline Leegaard. 



CHARTER IL 



KURVE Y OF TUE STATIONS. 



STATION F 23. 



On examination of the samples from the surface to the bottom we find at this sta- 

 tion rather homogeneous conditions throughout. While the température decreases from 

 1,63° (O mètres) to 0,60° (80 mètres) and increases up to 1,42° (100 mètres), the sa- 

 linity is fairly constant, viz: 5,43 °/ 00 from the surface to the depth of 40 mètres and 

 increasing up to 5,64 °/ 00 in the deeper layers. The oxygen-tension is registrated in four 

 depths; the water is somewhat supersaturated from the surface to the depth of 50 mètres; 

 at the bottom on the contrary the quantity of oxygen has sunk to 83 % of the satu- 

 ration-quantity. 



The plankton-distribution too shows homogeneous conditions, being fairly equal from 

 O mètres to 50 mètres, the numbers decreasing a little in the deeper layers. Especially 

 the diatoms, but also the peridineae and ciliata were fairly richly représentée!. The 

 dominating species were the following: 



Achnanthes taeniata i 



Chaetoceras Wighami without and with resting-spores. 



Melosira hyperborea 



Fragilaria cylindrus 



Thalassiosira baltica 



Gronyaulax catenata 



Mesodinium rubrum. 



As a standard of the distribution we may take the sum of the diatoms in the dif- 

 férent layers (table II): 



Table II. St. F 23. Number of cells pr. litre. 



With regards to the diatoms which have formed resting-spores (Achnanthes taeniata, 

 Chaetoceras Wighami and Melosira hyperborea) we notice, that they are rapidly decrea- 

 sing. The resting-spores are much more numerous than the spore-less cells; at the same 

 time Chaetoceras Wighami is sinking, the maximum lying in the depth of 30 mètres. 



Tom. XLV1II. 



