The Botany of Iceland - 01.12.1912, Síða 45

MARINE ALGAL VEGETATION
31
Iceland a physiognomy different from that of the surrounding sea,
the distribution of temperature being different even if the tempera-
ture is not in any important degree higher than in the East Ice-
landic polar current itself.”
The conditions of the currents in N. and E. Iceland are evidently
very complicated, and only the direction of the current of the
warm water has been given above in outline, but as the observations
are so few it is difficult to form an opinion as to how the condi-
Fig. 2. Map of Currents.
(Helland-Hansen and Nansen.)
tions of the currents aiong these coasts vary in other respects from
year to year or according to the seasons.
Further, other current-movements occur in the coast-water
which may be deemed to be of importance to the vegetation,
that is, sucli movements as are due to varying specific gravity. In
the summer (Nielsen, 52, p. 8) the surface-water along the coast
is lighter on account of its mixing with fresh water. A surface-
current from the coast outwards tlien arises, and an under-current
from the depth towards the coast. In the winter the surface-water
along the coast becomes heavier owing to cooling, and sinks. Then
a surface-current from the ocean towards the coast arises, and an
under-current from the coast towards the depth.