20 KJELLMAN, THE ALG OF THE ARCTIC SBA. 
Probable causes of the peculiarities in the general character of 
the arctic Flora. 
It has been shown, in the preceding exposition, that the general character of the marine | 
Flora varies in different parts of the Arctic Sea, and that this Flora, considered as a 
whole, presents several remarkable peculiarities of physiognomy, as compared with that 
of other parts of the ocean. That these peculiarities are essentially, though not ex- 
clusively, caused by certain cooperating physical circumstances peculiar to the Arctic 
Sea, I regard as a settled truth, although it is impossible at present, on account of 
our imperfect knowledge of the biology of the marine alge, to state decidedly which 
these circumstances are, and in what direction and with what power they act. I think, 
however, that the chief causes are the state of the ice, the configuration of the coast, 
the tide, the nature of the bottom, the salinity of the water, the temperature of the 
sea, the temperature of the air, and the want of light. 
The state of the ice. The influence of the ice on the vegetation of the Arctic Sea 
is decidedly unfavourable, the ice either 1:0) making the growth of alge impossible, 
or 2:0) making the period of vegetation too short for the alge to reach their full de- 
velopment, or 3:0) tearing off alge in development, or 4:0) making the bottém unfit for 
the prosperous growth of alge. The two first-mentioned effects are caused by the 
fixed unbroken land-ice, the two latter by broken-up ice-masses being carried along 
the shores by waves and currents. In the greatest part of the Arctic Sea there is 
formed during the winter a girdle of thick, coarse ice, which nearest the shores is pressed 
close to the bottom. At certain places this land-ice remains throughout the year, at 
others it is indeed destroyed, but usually only late in the year. I have already men- 
tioned that the ice-foot was found remaining everywhere along the shore at Cape 
Chelyuskin during our stay there at the end of August, and I may add here, that this 
ice was so strong and thick, that the shore could not probably get free from ice in 
the course of that summer. In 1875 the interior of Karmakul Bay in south Novaya 
Zemlya was still covered with unbroken masses of ice in the last days of June, and 
even in the middle of July this was in great part the case with the sound between 
north and south Novaya Zemlya’). It is clear that no alge can develop as long as 
this fixed land-ice remains, and it seems to me highly probable that when this ice, as 
is often the case, is not dissolved or destroyed ere late in summer, — consequently 
only a short time before new ice is formed again — the time left a marine vege- 
tation to spring up in such regions is insufficient for some alge to attain their full 
1) Cp. NorDENSKIOLD, Préven p. 14 and 22, and KyeLumMan, Algenv. Murm. Meer p. 59. 
I , P > 8 
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