Minerals in the Ocean
One of the minerals in the ocean is the same salt we use on food. This salt is a
compound of two elements, sodium and chloride. Chemists call table salt sodium
chloride. About 3/4 of the salt in the ocean is this "table salt."
The chart lists some of the mineral elements in the ocean and how we use them.
||Combined with chlorine for table salt
||Airplane parts, printing inks, insulating materials, medicines
||Medicines, dyes, fertilizers, paints
||High-test gasoline, medicines, photographic films
Gold and silver make up a small part of the minerals of the sea. Yet in a
stretch of water one mile long, one mile wide, and one mile deep, there are
ninety-three million dollars worth of gold and eight and a half million dollars
worth of silver. So far no one has found a profitable way to get these precious
elements out of sea water. If all the minerals in the ocean were spread over the
earth, they would make a blanket 150 feet deep. The amount of minerals in the
ocean keeps increasing. There is about one tablespoon of salt and other minerals
in a pint of sea water. This means there are now about 3 1/2 pounds of minerals
in each hundred pounds of sea water.
Life in the Ocean
The number of plants and animals on land is small compared to the number in the
ocean. Some of the animals in the ocean are so small you cannot see them without
a microscope. Some are the biggest on earth. They all must have food. Their
food, just as for land animals, depends on green plants.
plants of the ocean need light to make food, but, in other way, they are quite
different from the plants that grow on land. Most of the plants of the ocean are
very small. They are like those that sometimes get into a fish tank and make the
surface of the water turn green.
The small green plants of the ocean, together with small animals that feed on
them, are called plankton. Plankton plants are the basic food of the sea.
Each plant is very small. Thousands of them could fit on the head of a pin. Some
plankton can move about in the water. All of them, however, are carried around
by the movement of the water.
Most of the
plankton plants are diatoms. A diatom is a one-celled green plant without
roots, stems, or flowers. Under a microscope the diatom cell looks like a little
glass box made of two parts. These two parts fit neatly into one another. In
between is the living part of the cell, which contains chlorophyll. There is a
tiny slit in the glass-like box. Through this slit, the living part of the cell
gets sea water. Sea water contains the carbon dioxide and minerals the cell
needs to make food. It also contains the oxygen that all living things need.
These plants do not need roots. They get materials directly from the water in
which they float. These little plants usually grow above the ocean shelves
because the water there contains more of the minerals they need. They can grow
only as far down as light can reach – about 400 feet. Diatoms do not
reproduce by bearing seeds but more simply. Each diatom divides to form two. All
one-celled plants and animals reproduce in this way. Diatoms can reproduce very
rapidly. Under favorable conditions, diatoms may divide as often as 8 times in
24 hours. At this rate, you could begin with one diatom and have 256 the next
day if they were all still alive. What happens to plant plankton affects the
whole ocean. Without it, no life could exist in the sea. There are sea animals
that eat other sea animals, that eat other sea animals. But always at the
beginning of the food chain there is the green plant, the diatom of the sea.
Even the microscopic animal plankton must get their food from these tiny,
one-celled green plants.
Bread from the Sea
Plankton can be made into food for people. It can be pressed together
and dried. The result is a paste that is very high in food values. It is 50%
protein. It also contains fats, starches, minerals, and vitamins – in fact, every nutrient people need.
Its taste is mild, gritty, a little oily, and to some people it tastes like
broccoli. Other people say it tastes like pumpkin. Noodles, soup, ice cream, and
cookies can be made from plankton. And they taste good, too.
plants grow not only in the ocean, but also in fresh-water lakes. They can be
grown in tanks, too. All you need for a start is some of the plants, water,
sunlight, and minerals.
could also be used for fuel. When dried, they burn with a slow, hot flame like
coal. It was from living things like these that petroleum was formed millions of
years ago. We also get oil for paints, and chemicals for medicines, from
Seaweeds are many-celled plants that grow in the sea. Some of them grow to be
very big. These plants are quite different from large land plants. Land plants
need roots and stems to get water and minerals. Sea plants live in water. They
absorb this water along with minerals through all their parts. Food can be made
by all parts. Most seaweeds live at a depth of about ten to twenty feet. They
are supported by the water so they do not need strong stems to hold them up. If
seaweeds are out of the water, they sprawl all over the ground. They have
nothing to support them. Seaweeds do not have roots, but they do have
"holdfasts." These fasten to rocks or shells on the bottom of the sea.
Seaweeds vary in color. Those which grow nearer the surface of the water are
green. Farther down, seaweeds are brown and red. They have chlorophyll, but its
color is hidden by the brown and red. This brown and red coloring helps them to
use the smaller amount of light that reaches farther down into the water.
use a kind of seaweed called kelp to make into relishes, drinks, and even cake.
In California, some kelps are sold as candy.
If you ever
felt seaweed just out of the water, you know it is slippery. A gelatin-like
substance can be taken from it which is used by scientists for growing bacteria.
It is also used in making jelly. Seaweeds are also rich in iodine.
Fish of the Sea
Fish contain proteins, minerals, and vitamins. In all food values fish are equal
to, and sometimes better than, other meat. Some fish and sea food taste very
"fishy" and some can hardly be recognized by taste as fish or sea
food. There are recipes for cooking fish to please almost every taste. When
chefs prepare big banquets, one course in the dinner is usually a fish course.
Carefully prepared fish can be delicious.
their rich mineral content, are one of the best fertilizers there is. Ground-up
fish heads, scales, and bones are used as fertilizers today. Livestock and pets
are sometimes fed ground-up fish. This provides valuable minerals and proteins
which help animals grow. Cod-liver oil is rich in vitamin D. In the winter, when
there is not much sunshine, cod-liver oil can provide this vitamin for your
One way to increase our food supply from the ocean is to "farm" the
ocean. There are underwater farms for oysters. Oysters live in the shallower,
warmer waters of all oceans. They are often harvested wild by fishermen, but
more and more they are grown in carefully prepared oyster beds. By special care,
the oyster farmer can produce more and better oysters. Not all waters can be
used for oyster farms. Some bays have become polluted. Oysters that grow in
polluted water are not safe to eat.
plankton, which is rich in iron and iodine. Therefore oysters are an excellent
food for man. They are high in vitamins and in proteins.
The Great Mammal of the Sea
the nineteenth century, great sailing fleets roamed the Arctic and Antarctic
oceans looking for whales. Men traveled far away from home, sometimes for three
years, to hunt for whales for the oil – as much as 15 tons of it from a single
say that whales were originally land animals. They have found fossils which show
that whales once lived on land. Judging by the tremendous teeth and jaws of
these fossils, scientists believe that land whales must have been powerful
beasts. No one knows how whales became sea mammals. Perhaps generation by
generation they moved farther and farther out into the sea to get food. Their
bodies gradually became more suited to life in the water. Their hind legs became
smaller and smaller. Today hind legs cannot be seen outside the whale at all.
Their front legs changed into flippers for steering and balance. All these
changes took place slowly over thousands and thousands of years.
The whale is
the largest animal on earth. One kind of whale, called the whalebone whale, eats
plankton and shrimp. Since whales are mammals, they are not able to use oxygen
from the water as fish do. Whales usually swim just beneath the surface of the
water. Every few minutes the whales come to the surface to breathe. As a whale
comes to the surface, it blows a tremendous spout of vapor from its nostrils,
which are on the top of its head. In the air, the vapor condenses so that it can
be seen. The spout is followed by a whistling rush of air into the nostrils.
Then the whale disappears under the surface of the water again.
develops a layer of stringy white fat, called blubber, under its skin to protect
it from cold water. In very cold water, this layer may be as much as 9 inches
deep. Whales that live in warmer waters need less blubber. When the whale
travels through warm water, some of its blubber may be used for energy because
it is hard for it to find food in warm water. Whale oil is made mainly from the