The Banner-Democrat. [volume] (Lake Providence, East Carroll Parish, La.) 1892-current, 1902-04-05
LIFE IN TILE SALT SEAS.
HOW ZIG A CROP OF FISH 1T IS
SAFE TO HARVEST.

Measuring the Microscopic Vegetation ON
Which Marine Animals Feed - There
Are Two General Glasses - loaf of the
Waters Denixens survive ON lants.
To estimate with any degree Of pre-
cfsi0n the quantity of fish which may
properly be taken from the seas every
year appears to be no easy task. Some
years the yield is better than others,
but this is largely a matter of luck.
1t is only after long series of fail
ures to catch the old time abundance
of mackerel. herring or cod that one
can tell that there is an actual dim
ipution in the production. and even
from statistics of this kind only an
approximate notion can be had of the
right amount to capture in a single
season.
1t is believed, however, that there
Is much better way to get or the re-
suit, though 1t Is trife circuitous.
In the ocean, as on land, animal life
depends on vegetation for its support.
There are many carnivorous creatures
IT. the water, but the little fishes and
animalculae on which they feed live
on plants. And in the water, as on
land, plants derive their sustenance
from inorganic substances which they
manufacture into living tissue. If,
therefore, SUCH a survey We're made OF
the seas as would show now much
vegetation was produced there, then
it might be possible to figure out the
amount of animal life that could be
sustained thereby. Thus, it has been
found that an acre Of cultivated land
in Prussia will produce about Is
pounds of beef year. There are nat
uralists who hope to establish SINH
lar ratio between the vegetable and
animal life of the ocean. Karl Brandt,
in a paper which has been translated
for the latest volume OF Smithsonian
Reports $4,000, tells something about
their plans AMI methods.
In the sea there are two general
classes of vegetation. One includes
seaweed, kelp and other plants of con-
siderable size, which are found only
along the shore. The other embraces
microscopic organisms, each consist
ing of only a single cell, like the dia-
tom, and distributed all over the
ocean, though not flourishing at great
depths. Plants need light, whether
their abode be terrestrial or marine.
Herr Brandt quotes Schutt as saying:
1.-THE sailor, who fancies he has pure
water under him, really sails every
where in the midst of a rich vegeta-
t1on.' And this microscopic vegeta-
ton it is which sustains animal life,
and which corresponds to the pastures
where sheep an cattle fatten. The
seaweed along the shore bears about
the same relation to the fishes as the
forests DO to land animals, so far as
furnishing food is concerned.
The growth of terrestrial plants is
facilitated by the presence CT certain
compounds of nitrogen. These same
fertilizers produce the same effect in
the ocean, and owing to drainage from
the land they are more abundant near
shore than out in midocean; hut that
they are intimately connected with
the development Of animal as well as
vegetable life there is easily proved.
In Germany much attention has been
given to raising carp. Susta, who has
written on the subject, says that in
the poorest ponds the yield is about
IL pounds of fish to the acre. The
better ponds produce from three to
six times as much, whereas still 9TH
ers, into which liquid fetilizers drain
from farms, give results about 20
times larger tnan those first cited.
Consequently, in the researches which
are now being conducted into marine
life, the chemistry of the sea water,
as Well as the abundance Of micro
scopic vegetable and animal forms, is
carefully considered. Attention Is al
SO given to the presence Of those
species of bacteria which have the
power of promoting and retarding the
development of nitrogen compounds.
When one reads about ''plankton"
expedition, he may understand by that
expression a ship which ia equipped
with apparatus for bringing up sam
Piles of sea water for such an investi-
cation as has just been described. A
net Of very fine mesh is employed in
this work, and is so managed
as to bring up vertical column of
water at considerable depth. Pains
are taken to count the various or
ganisms found in given volume of
fluid. Owing to the incessant stirring
up of the sea, figures for one locality
are believed to be fairly representa-
tive of wide area. But an ideal sur
vey Of this kind would embrace fire.
quent observations through a full
year; and, though work of this kind
has been carried on in all attitudes in
the last dozen years, some Of these in
quiries were only for few months.
Two results have thus far been
reached by such investigations. Mi
croscopic vegetable and animal life is
found to be more abundant in shallow
seas than in deep ones. Herr Brandt
accounts Tor this TACT by SuppOsing
that the fertilizing material from the
land is less diluted In the former re-
gions than in the latter. The other
conclusion which has been reached is
that life is more abundant in arctic
than in tropical waters, thus reversing
the situation which exists on land. To
explain so strange an anomaly, it is
suggested that one nutriment is more
abundant in cold seas than in warm
ones, though just why this should be
30 it is not easy to say. Perhaps the
bacteria which favor the production
of nitrogen compounds are more nu-
nerous in the one zone than in the
other. or, perhaps, the other kind,
which breaks up and spoils those COM
pounds, is in excess In tropical eli
mates. But this is a pOint which has