The Botany of Iceland - 01.12.1912, Síða 50

36
H. JÓNSSON
board the mail steamer “Laura” on its route from Scotland to Ice-
land during the years 1897—1904.
Between longitude 17° and 18°, near the coast of Iceland, in a
south-easterly direction from Dyrhólaey, the mean temperature of
the year (1897—1904) is stated (44) to be 8.8° and the mean salinity
during the same period 35.19.
The main features regarding the temperature of the ocean
around Iceland then are as follows — At the south coast warm,
pure Atlantic water of a high (above 35 %o) and somewhat varying
salinity occurs; at SW. Iceland there is a somewhat similar sea; at
NW. Iceland and N. Iceland there is Atlantic water mixed with cold
water of low salinity from the East Greenland polar current; and
lastly, at E. Iceland Arctic water occurs (with a temperature of 0° to 2°
and salinity from 34.6 per cent. to 34.9 per cent. [Helland-Han-
sen and Nansen, 27, p. 287]): the East Iceland polar current mixed
with water from the Atlantic current.
The change of temperature in the surface-layers of the water,
the cooling process during winter and the heating process during
summer, reaches down almost as deep as the algal vegetation, and
is consequently of no slight importance to the latter.
b. The Temperature in the Fjords. Respecting the tempe-
rature of the surface-watei’ of the ocean throughout the year infor-
mation is given in the “Meteorologisk Aarbog” (Meteorological Year-
book) regarding three stations in Iceland: Papey, Grímsey and Styk-
kishólmur. The following figures show the seasons’ mean tempera-
ture of the ocean for a period of five years (1902—1906), chosen
arbitrarily. Grímsey is omitted, however, as the observations there
have often been incomplete.
Winter Spring Summer Autumn
Papey (E. Iceland) 0.9° 1.7° 6.0° 4.3°
Stykkishólmur (SW. Iceland). 0.4° 1.8° 9.6° 6.4°
Vestmannaeyjar1 (S. Iceland). 4.1° 6.1° 10.4° 7.0°
The winter in Papey is warmer than in Stykkishólmur, and the
monthly mean temperatures during the winter, of the period mentioned,
are there all positive; while in Stykkishólmur, February (—0.8) and
March (— 0.2) have negative numbers. The sutnmer is much warmer
1 The íigures for the Vestmannaeyjar constitute the mean of the period from
July lst, 1877 to Dec. 31st, 1906. According to þorvaldur Thoroddsen, Lysing
Islands, 2. Bd., pp. 350—351, Kaupmannahöfn 1910.