The Botany of Iceland - 01.12.1930, Qupperneq 14

4
II. M0LHOLM HANSEN
According to Thoroddsen (1914) these features are of great ini-
portance in their bearing on life in the sea, both as regards its flora
and fauna. We find, in fact, on the north and east coast, a flora
and fauna of arctic character, whereas those of the south and west
coasts are of temperate character. Up to the present, this has been
confirmed by investigations on the flora of marine algæ, plankton,
and the fish fauna, as well as deep sea and bottom fauna. The
same conditions seem to be of no slight importance as regards life
on land, as the present research inter alia will show.
The temperature along the coast shows, according to Thorodd-
sen, the following values: On the south and west, the mean surface
temperature is 5—7°C., while to the north and east it is somewhat
lower, 3—4° C.
At the Vestmannaeyjar (South Iceland) the surface water during
the coldest months (Decbr.—Febr.) shows a monthly average of abt.
4° C., and in the hottest months (July—Aug.) abt. 11° C., the annual
mean temperature being abt. 7° C.
Stykkishólmur (W. Icel.) has for Febr.—March temperatures of
0.3°—0.4° C. and July—Aug. 10.4°—10.6° C., with an annual mean
temperature of 4.9° C. Grímsey (N. Icel.) a March temperature of
0.7° C., August 7.4° C., with an annual mean of 3.8° C., and Papey
(E. Icel.) has a Febr.—March temperature of 0.4°—0.5° C., Aug.—
Sept. 6.6°—6.2° C. witli a mean temperature for the year of 3.2° C.
It will be seen from this that the temperature of the surface
water decreases parallel with the voluine of Gulf Stream water.
From South Iceland west and northward round to East Iceland we
have the following values for mean annual temperature: 6.9°—4.9°—
3.8—3.2° C. East Iceland has the lowest mean temperature and
the greatesl volume of the Polar water; South Iceland the greatest
volume of Gulf Stream water and the highest mean annual tempe-
rature.
The temperature of the air is closely correlated to this (see
Table 1), being, however, nearly always lower than the surface tem-
perature of the sea water, the dilference amounting on the average
to a couple of degrees. We find, for instance for the temperature
of the air, the following mean values: 5.1°—3.0°—1.5°—2.4° C. that
is, following the coastline round from S-W-N-E.
The grealest dilference is apparent during the coldest months
of the year, October to March, less in summer from April—Sep-