638 



NA TURE 



{Oct. 30, 1 8 



graphic print of the iris of the eye does not afford a 

 trustworthy unit of measurement. 



Francis Galton 



ON THE ALGIC FLORA OF THE ARCTIC SEAS 



AMONG the fields of research opened to science by 

 the Swedish Arctic expeditions of recent years the 

 botanical one is that which has been cultivated the most 

 assiduously and with the best results. The contributions 

 which Swedish men of science have made to our know- 

 ledge of the flora of the Arctic regions are varied as well 

 as important. They embrace the higher as well as the 

 lower forms, both the species invisible to the naked eye as 

 well as those of greater size, and the varieties hidden in 

 the Lip of the ocean as well as those which the student 

 encounters on terra firma. Swedish botanists have par- 

 ticularly increased our knowledge of the remarkable flora 

 of the sea. Thus instead of, as only a few years ago, our 

 being ignorant as to whether there really was a flora at 

 the bottom of the Arctic seas or not, we are now more 

 familiar with the alga; flora of these regions than many 

 another in far more southern latitudes. 



Of the Swedish botanists who have particularly devoted 

 their time and energy to the study of the flora of the 

 Arctic seas 1 must mention the following gentlemen, mem- 

 bers of the Royal Academy of Science of Stockholm : 

 Messrs. J. G. Agardh, P. T. Cleve, F. R. Kjellman, 

 and E. G. Kleen. The reason which specially prompts 

 me to discuss this subject here is the recent appearance 

 of an important work by one of these algologists, Prof. 

 Kjellman, viz. " Norra Ishafvets Algflora," with thirty-one 

 illustrations, which forms part of Nordenskjold's " Vega- 

 expeditionens vetenskapliga iakttagelser," a work winch 

 has from time to time received favourable mention in 

 this journal. 



Prof. Kjellman has, as the representative of botany, and 

 particularly the branch termed algology, participated in 

 four Arctic expeditions, during which he has visited Fin- 

 marken, Spitzbergen, Novaya Zemlya, in Europe, and 

 long stretches of the coast of Siberia, in Asia. Two of 

 these expeditions, the one to Spitzbergen, 1872-73, and 

 the Vega Expedition, 1S78-S0, were attended by winter- 

 ings in the Arctic regions, during which time Prof. Kjellman 

 enjoyed an opportunity, never before accorded to an algo- 

 logist, viz. that of studying the flora of the sea at all 

 seasons. His algae flora, in consequence, not only forms 

 a complete index of the species and varieties of the 

 algae of the Arctic seas, their form, construction, and 

 geographical distribution, but it gives us also an insight 

 into the vital functions of these plants, and explains to us 

 the conditions under which they exist. I intend in this 

 paper to refer briefly to the present position of this science, 

 to whi :h Prof. Kjellman has contributed such a great 

 share. 



The Arctic Ocean covers, geographically speaking, the 

 sea north of the Polar Circle. Within this area there is, 

 however, a vast tract of sea where there is no ice either 

 winter or summer. This is the sea around Northern 

 Norway through which the Gulf Stream flows. On the 

 other hand, there are tracts south of the Polar Circle which 

 rival the coldest parts of the Arctic Ocean on the point 

 of ice. To these belongs, in the first instance, the part. of 

 the Atlantic washing the south-eastern shores of Green- 

 land, which receives from the north a cold Polar current 

 full of icebergs. 



From a hydrographical point of view, however, the Arctic 

 Ocean is far more naturally limited if we deduct from it 

 the part around Northern Norway and add to it the sea 

 around Southern Greenland. From a botanical point of 

 view, too, the Arctic Ocean is thus liaiited in a more 

 natural manner. To the part of the Arctic Ocean cut off 

 by this arrangement Prof. Kjellman proposes to assign 

 the name "The Norwegian Polar Sea," and in the work 



refi flBk tbovi di tl th the algae flora of the true 

 Arct7^^*_an, according to the hydrographical and botani- 

 cal theories, as well as that of the Norwegian Polar Sea. 

 As the conditions under which the flora of the true Arctic 

 Ocean lives lend to the same a heightened interest, I will 

 discuss this flora at more length, and finally add some 

 words on that of the Norwegian Polar Sea. 



In a sea like the Arctic Ocean, where ice is found in 

 large quantities all the year round, it seems, at first sight, 

 that no flora could exist, and it is, indeed, true that great 

 parts of the Arctic Ocean are, botanically speaking, mere 

 deserts, but this is not caused, as I will presently show, 

 by the low temperature of the sea, but by other causes. 

 Strangely enough, some algae have become accustomed 

 to be surrounded by a medium the temperature of 

 which never, or at all events but seldom, rises above 

 freezing-point, and in many instances they have indeed 

 flourished greatly therein, of which their luxuriant growth 

 bears evident proof. 



When I just said that large tracts of the Arctic Ocean 

 are botanically deserts, I did not thereby mean that the 

 deepest parts of the sea were void of flora, as this is really 

 the case in all, even the warmest, parts of the oceans 

 of the globe. The algae flora is only to be found within a 

 smaller or larger belt along the coasts of the continents 

 and islands, and even within this belt, where the depth 

 does not prevent the existence of algae, they are not found 

 everywhere. Another condition too must be present for 

 the existence of algse, viz. that the bottom be rock, boulders, 

 or marine shells, in brief, formed of large objects which 

 can serve as " moorings " for them. Thus, where the 

 bottom is sand or clay the regular algae flora is absent. 

 In the eastern parts of the Arctic Ocean the latter kind 

 of bottom is very common. Nearly along the entire coast 

 of Siberia, and in long stretches near Novaya Zemlya and 

 Spitzbergen, the bottom is formed of fine sand and clay. 

 Algae are here sought in vain, as they are, in fact, in 

 localities with a similar bottom all over the world. Only 

 on the north and north-western coasts of Spitzbergen, and 

 in several places along the west coast of Greenland, the 

 bottom consists of such hard materials as are favourable 

 to a copious algae flora. 



This explains to a great extent the existence of the 

 botanical deserts, referred to above, in the Arctic Ocean, 

 but there are also other causes. Before I deal with these, 

 however, I must explain the manner in which the bottom 

 of the Arctic Ocean is divided according to the flora at 

 various depths, as suggested by Prof. Kjellman. 



He distinguishes between three bottom regions, viz. the 

 littoral, or what may be called the upper shore-belt, the 

 sub-littoral, or lower shore-beh, and the c littoral, or deep- 

 sea belt. The upper shore-belt embraces that part of the 

 bottom which lies between the neap and high tides, the 

 lower shore-belt the part that stretches from the former 

 down to a depth of 36 metres, and the deep-sea belt the 

 part below the latter depth. 



Of these three belts, one, the upper belt, contributes 

 greatly, and in a striking manner, to make parts of the 

 Arctic Ocean flora-less. Within far the largest parts of 

 the ocean this belt is void of all vegetation, and the cause 

 of this is easily discovered. It lies in the ice. Thus 

 every winter a girdle of coarse, firm ice is formed along 

 the coast, and near the shore reaches to the bottom. 

 In some places this ice lies all the year round, and in 

 others it certainly disappears, but generally late in the 

 season. At Cape Chelyuskin during the Vega Expe- 

 dition the " ice-foot," viz. the shore-ice, was lying firm 

 at the end of August. Where the land-ice thus remains 

 throughout the summer no algae can, of course, develop, 

 and where it disappears only in the autumn the time is too 

 short to allow of any growth. 



Nearly as detrimental to the flora as the land-ice are 

 the broken-up ice-masses, which during the summer are 

 driven hither and thither by winds and waves. These 



