222
THE SEAS
-as
on
land, they are of great signicance in the lives
of the animals living in the sea.
For whereas
most
land . animals are warm—blooded and have special means
forkeeping the temperatures of their bodies at a constant,
in
the
sea
most
animals
are
cold—blooded and must
take
up
the
temperature of the surrounding water. '
If our temperature rises only a few degrees the chemical
.
reactions are gone through at a dangerously increased
rate
and
give rise to fever.
We
can
easily imagine
therefore that the passage of an animal into water ve
or six degrees warmer than that in which it had been
living: may have a prof0und effect upon it.
It is probably
for this reason that the boundariesto the distribution of
many animals in the sea. are those of temperature.
(See
,
page 89.)
,
_
Water requires a tremendous amount .of heat energy
to raise its temperature; the amount of heat necessary
to raise the temperature of, a cubic foot of water by. one
.
degree would—raise by the same amount 3,000 cubic feet
.
of air.
This is why in the
never has time
to reach the high temperature of the surrounding air
except sometimes just at the surface.
For the same reason water is very slow to give up its
heat when once it. is gained, and we notice that in winter
,
the sea is far warmerthàn ;the
and-acts as
of heat.
This explains why the climates of oceanic islands
and coastal lands are muchfmore equable;than those of».
countries in the interior of great continents.
,
The inuence
0f—0ceanic currents upon climate:is well shown by a com—
parison of that of the British-Isles, whose shores are bathed
by a branch of the GulfStream, with the climate of Labrador
“
which lies in the
-
.
.
.
'
At the same
_receirœdat the sea surface is
-
imperceptiblyslôwly- conducted away into deeper layers,