24 



ASTRID CI.EVE-EULER, QUANTITATIVE PLANKTON RESEARCHES IN THE SKAOER RAK. 



Table 30. S. Skag. 0. 54° 41' N., 11° 24' E. 26. IV. 1913. 



CD o 

 fe 



S £ 



0) 3 



"3 



ca 



•- o 



•ä t. 



.a d 



_c o 

 a 

 £ £ 



<.2 



c 



.2 



C CO 



.3 t. 



c o g 



B *" 3 



>> c 



o 



"C ■ 



o 

 c 

 s ■ 



5 



C « s 



B B o 



.2 ^ 



» o 

 O"" > 



cS 



S.B 



ii 



CS 3 



>- c 



CD 



o 



= 

 c 



t* 



CD 



— CD 



s -g 



P. s 



t» 



ii CO 



■2-3 S 



CD — CD 

 O O ,fl 



ja -S a 



o 2 — ■ 

 o ° £ 







10 

 20 

 30 

 40 

 50 

 00 

 73 ' 



0,81 



4,71 

 4,34 

 4,08 

 5,28 

 5,18 

 5,10 

 5,11 



20,99 

 24,10 

 20,94 

 32,03 

 33,20 



33,58 

 33,77 

 34,45 



10,47 

 19,16 

 21,39 



25,86 

 20,29 

 20,56 

 20,71 

 27,26 





450 



200 





400 







1,850 



250 



150 



1,650 



100 



140 



760 





SO 



1,000 



40 



100 



1 ,220 



80 



50 



150 



50 



100 



40 

 20 



50 

 100 

 100 

 100 



20 



50 

 250 

 300 

 150 

 220 



40 



800 

 1.500 

 3,450 

 2,300 

 1,440 

 1 ,420 

 1 ,520 



200 



2,550 3,500 0,050 



650 1 ,750 2.450 



1,350 ] 2,850 4,450 



350 1 900 1,750 



320 580 940 



300 480 780 



200 : 020 980 



1 50 ! 450 750 



Table 31. S. Skag. 5. 57° 42' N., 9° 51' E. 25. IV. 1913. 



Depth 



CD o 



& 



£ £ 



CD 3 



Salinity °/oo 



-»a 



'5 



c 



CD 



Q 



Thalassiosira 

 Norden- 

 skiöldii 



Thalassiosira 

 gravida 



Paralia 

 sulcata 



Guinardia 

 flaecida 



Leptocylin- 

 drus danicus 



Rliizosolenia 

 fseröensis 



Rliizosolenia 



hebetata 

 f. semispina 



Chaetoceras 

 debile 



Chaetoceras 

 decipens 



Chaetoceras 



diadema 

 with spores 



Chaetoceras 

 sociale 



Diatoms 



total 

 numbers 







0,49 



34,00 



20,72 











3,200 





200 3,100 



450 



7,100 



10 



0,35 



34,22 



26,90 











4,100 





200 10,800 







, 15,100 



20 



5,69 



34,34 



27,10 



50 



250 



400 





50,100 



3,150 



900 l 65,150 



5,0C0 





4,650 130,800 



30 



5,42 



34,45 



27,21 



4,000 



150 



450 





17,800 



1,150 



1 ,000 29,300 

 + 150 2 



3,000 ?Ö0 3 



19,850 79,900 



40 

 50 



5,31 

 5,28 



34,45 

 34,52 



27,22 



27,28 



750 

 40 



040 



750 

 340 





900 

 1,440 



40 

 20 



60 1,350 



+ 20 2 



160 1,220 



(150) 

 220 



750 



4,700 11,340 



•JO 



5,580 12,420 



A high salinity all through the water-column indicates here the absence of affluents 

 from the Baltic; it is the place of the reversion-current round Skagen. In this very salt 

 water, Leptocylindrus does not thrive. When it increases not inconsiderably in quantity 

 from 20 m downwards, in spite of a steadily growing salinity, this may depend on a large 

 sinkingand spreading coefficient from the proximate centre of development farther east- 

 ward. Near the same level of 20 m also all the other diatoms spring np in number or 

 begin to appear: to this biological limit eorresponds a feeble hydrographical one, the tem- 

 perature falling with i / a of a degree, varying more slowly afterwards. The dominating 

 Chaetoceras is here Ch. debile, with a maximum of 65,150 ind. per 1 at 10 m already sur- 

 passing Leptocylindrus in frequency. Other species, not indigenous in our coastal waters, 

 Ch. diadema and especially Ch. sociale begin to become a feature, that we shall find much 

 more marked at next station, and remnants of the winterly Sira-plankton are not sparse. 



1 Much detritus i» this sample. 



s The undermost number denotes a form, twice as thick as usual. 



3 Cursives denote the presence of spores. 



