10 



ASTEID CLEVE-EULER, QUANTITAT1VE TLANKTON EESEARCHES IN THE SKAGER RAK. 



and of too recent an arrival for having yet allowed any local multiplying, as in the coast- 

 waters farther eastwards. 



Table 6. S. Skag. 5. 57° 42' N., 9° 51' E. 16. VIII. 1912. 













s 













■a 



CO 



1 "> 



-»a 



0. 



P 



lo 



a, 



<D 3 



o 



>> 



o 



>> 



*C0 



B 



B 5 



3 05 



03 O. 



t. CD 

 CD O 



S 2 



3 OJ 



'-58 



fe s 



s 



3 to 

 ■K 3 



t» <o 



c3 3 

 t. cl 



CD 



s 



3 03 

 •— O 



03 3 



B te 



.2 0. 



£ B 

 » O 



2 „ 

 .5 3 



g 5 



1, 



"Il 



03 3 



Si 

 SS 



2 S 



* 2 



?ridinia 

 total 

 umbers 



ridiniale 

 total 

 umbers 





H *» 



03 

 t» 



p 



°J 



u§ 







O 



O — 



O 



"- 1 B 

 cd w 



Ä u 



c 







15,55 



30,82 



22,67 





20 





20 





20 



60 



20 



(+20) 





100 



(+20) 



10 



15,89 



31,96 



23,46 





20 



20 



20 





60 



120 



100 





300 



20 



16,29 



33,06 



21,20 





10 



20 



20 







70 



70 



( + 20) 



10 



200 



(+20) 



30 



10,13 



33,19 



24,36 







10 



10 







20 



10 





70 



40 



15,58 



33,49 



24,70 







10 





10 





20 



10 



40 



270 



One gets a still stronger impression of a restless exchange of water at this station, 

 when considering the distribution of the infusorians, that part of the plankton, 

 which is generally most exclusively bound to the uppermost layers during seasons of 

 vitality. Here we find, curiously enough, a slow increase downwards and an almost sta- 

 tionary average number for the dominating form, Tintinnus subulatus, while our indigenous 

 Laboece are absent. 



Table 7. S. Skag. 6. 57° 56' N., 9° 40' E. 16. VIII. 1912. 



Q* 

 cu 

 P 



(Do 

 O. 



<D 3 



O 

 O 



>> 



'a 



02 



D 



>> 

 -*a 



CO 



a 



CD 

 P 



.5 a 



a -g 



03 



■S a 



Rhizosolenia 



alata f. 



gracillima 



.5 ._ 

 'a 'S 

 £ 



o 00 

 CO -O 



a 



N ti 

 g 3 



Naviculoid 

 diatoms a. 

 Nitzsehiae 



Diatoms 



total 

 numbers 



ö 



03 

 ti 

 O 

 O 



Peridiniales 



total 



numbers 



co to 



3 3 



G .2 



■s-g 



Infusorians 



total 



numbers 







15,39 



30,28 



22,29 















200 



340 





220 



10 



15,39 



34,58 



25,58 







1,290 







1,290 



40 



70 





120 



20 



14,66 



34,69 



25,76 







140 





10 



150 



10 



85 





50 



30 



11,10 



34,34 



26,27 



720 



2,160 



220 



20 



140 



3,310 



520 



660 





110 



40 



11,00 



34,34 



26,27 



600 



2,650 



190 



50 



70 



3,590 



430 



470 





40 



50 



10,89 



34,34 



26,31 



620 



850 



160 



20 



80 



1,765 



340 



450 





110 



60 



10,81 



34,36 



26,33 



570 



830 



170 



40 



50 



1,680 



460 



540 





50 



80 



8,05 



34,69 



27,04 



320 



430 



80 



270 



70 



1,330 



30 



100 





30 



100 



6,85 



34,94 



27,43 



60 



290 



50 



120 



70 



705 





40 





10 



The above table, rendering some figures from the central Skager Rak, illustrates 

 in a striking way how a hydrographical limit coincides with a biological one, as long as 

 the former is sharp, thanks to a fresh invasion of a new kind of water. Somewhere be- 

 tween 20 and 30 m, there is a rapid spring in the temperature of more than 3,5°, then as 

 well temperature as salinity become stationary for more than 30 metres. Now the plank- 



1 Peridiniu in the tables always denotes the species of the genus Peridinium; the tribe, to which it 

 belongs, being iuserted as Peridiniales. 



