The suburban citizen., 1901-08-24
THE SEA Bottom.
Fhysieal Conditions and Forms af Life OF
tho Ocean Depths,


the Ocean Depths,
The following facts relating to the
deep sea and its forms of life are de-
rived from an address delivered re.
Gently by Professor c. G. Nutting, Of
the Iowa University, who has himself
been actively engaged in deep-sea ex-
ploration.
probably the most remarkable of the
conditions Of deep-sea life is the enor-
nous pressure, which varies, of course,
with the depth. At the average depth
say 1000 fathoms, the pressure Is
about two tons to the square inch Of
SURFACE, and at 1000 fathoms each
square inch Of surface is subject to
pressure Of about four tons. This
fact led the earlier physicists to main
tam that organic life was impossible
IN the great depths. 1t has been
proved, however, that animals of all
classes, except the highest yerte-
brates, have been dredged from even
the deepest abysses of the ocean.
The great pressure to which they
have been subjected has curious eff
feet on the deep-sea fishes when they
are brought to the surface. Under
these circumstances, being released
from the accustomed pressure they
fall to pieces as it We're. The eyes
bulge out, the swim-biadder protrudes
from the mouth, the scales fall off and
the flesh comes off in patches. Now,
fhngn N1,a,
pear when brought to the surface,
were doubtless respectable enough Ia
their proper habitat. In the depths of
the ocean they are doubtless no more
conscious of the pressure of four or
five tons to the inch than are we of the
fifteen pounds of atmospheric pressure
under which we live and move and
have our being.
Another remarkable condition Of life
In the ocean depths is that Of pro-
found darkness, so far at least, as
sunlight Is concerned. 1t has been
found that Photographic plates are I'M
affected beyond a depth Of 125 fathoms
OF clear water, all or the major part
Of the suns light having been absorb
ed before Ii has reached that depth.
Professor Alexander Agassiz assumes
as probable that at 200 fathoms the
light from the sun is possibly that Of
a clear starlight night. Below that
depth all objects would seem necessa-
rily to be involved in darkness as COM
plete as though they We're immersed
in sea of ink. And yet there is evil
dence tending to prove the presence Of
light at depths far in excess of this.
According to Professor Agassiz, by
far the majority OF animals living at
depth Of about 20O0 fathoms have
eyes, either like their allies of shallow
water, or else rudimentary, or some
times very large, as the huge eyes de-
yeloped out Of all proportion in some
Of the abyssal crustaceans and fishes.
Without light these organs would, Of
course, be useless. Sunlight being out
of the question, it Is now held that the
light which enables these animals to
see is phosphorescent.
A very large number of crustaceans
are highly phosphorescent. Many of
those having large eyes are Of this
class, and are particularly active in
movement and vOraclous in appetite.
They feed on minute organisms for
the most part. and it can hardly be
doubted that they use their phospho-
resent powers for the purpose Of IL
Eliminating their surroundings and re.
vealing their prey.
A third condition Of the ocean depths
Is a temperature uniformly low, prob
ably below forty degrees, while in
many cases the temperature is actu-
ally below the freezing point of fresh
water This condition is kept up by
the ocean currents, the general drift
Of the surface waters being from the
equator toward the poles, while the
deep-sea currents are in the opposite
direction. The general impression
that a high temperature is more ia
vorable than a low one for the best
development of animal ife is certainly
not true Of marine animals in general
If other conditions are favorable a
luxuriant fauna will be developed in
any temperature short of the freezing
point Of salt water.