Riches from the Sea
from the book, "Petrified Lightning"
Riches from the Sea
amount of water on the earth, an estimated 326 million cubic miles, is too
great to comprehend. An enormous proportion, approximately 97.2 percent, fills
the oceans of the world.
pay a great deal of attention to the exchanges of water among the oceans, the
atmosphere, and the continents. This unending circulation of the earth's water
supply, named “the hydraulic cycle,” is somewhat complex in its extent and
process. Stated simply, water is constantly evaporated from the oceans and into
the atmosphere. Prevailing winds blow this moisture—laden air over the land,
where the water is precipitated out as rain or snow. This water is then carried
back to the sea by rivers and underground flow. The cycle, completed and
repeated endless times, has persisted since oceans and lands first became the
dominant features of the evolving earth.
its trip back to the sea, flowing water comes in contact with most elements
present in the upper part of the earth's crust—over half of the 103 known
elements. Some of the material is dissolved and carried to the sea in solution.
As a result, the mineral richness of the sea is immense; it would be a rare
phenomenon for elements and minerals that occur on land to be absent from the
oceans—and that includes gold!
oceans of the world carry so much gold in suspension that if mining it to its
fullest were possible, enough would be harvested to give each person on earth
about nine pounds of solid gold. Scientists know each cubic mile of seawater
holds about 25 tons of gold. That's a total of 27 million tons of gold in the
world's oceans. Although this is an impressive amount, so is a cubic mile of
ocean. The gold is dispersed throughout the water, present in such minute
concentrations that no method has yet been devised that can extract it
for example, a modest—sized room 10 feet wide, 12.5 feet long,
and 8 feet high. These dimensions represent a volume of 1,000 cubic feet.
Filled to capacity with seawater, the room would contain only about five
one—thousandths (.005) of an ounce of gold. That is certainly not enough to get
excited about, and of course not enough to try to extract. Only about five
ounces of gold can be found in a billion ounces of seawater (one part per 200
million). So don't bother packing your gold pan for the next ocean voyage. All
of the many scientific attempts to recover the minute flecks of gold strewn
throughout the sea have failed.
present the only metal successfully extracted from the sea in commercial quantities
is manganese. It occurs as nodules carpeting the ocean floor in an almost
continuous layer, so in many places it is easy and economical to recover. The
manganese appears to be precipitated from the water and forms over other
mineral deposits; within the nodules are about 40 different minerals and an
occasional shark's tooth, whalebone, or piece of pumice. The nodules are valued
more for the other minerals (cobalt, zinc, nickel,
copper) than for the manganese.
85 percent of all substances dissolved in the oceans is
sodium chloride, the mineral halite, known best as common table salt. Each
cubic mile of seawater contains over 166 tons of dissolved salt, enough to
supply the world's demand for several years. Scientists have calculated that if
all the salt were extracted and spread over the land it would form a layer more
than 500 feet thick!
some places salt is still recovered from seawater by simple evaporation, the
same method used by the Chinese as early as 1000 b.c.
Most salt, however, is mined from brine wells and salt domes, which show that
the continental area where they are found was once covered by oceans. Being cut
off from the sea the water was subject to evaporation, and the mineral matter
carried in solution eventually precipitated out, yielding in many cases
enormous concentrations of salt ready for the dinner table. Of course this is
an oversimplification of the complex mining methods that are applied, but salt
the commercial product from phosphorite, is used extensively
as a fertilizer and, because it is much in demand, is a valuable economic
commodity. Scientists know that a rich deposit of phosphorite
lies on the seafloor off the coast of San Diego and that economic recovery is quite feasible.
However marketable the deposit may appear, it will never be mined because the
area was once a naval firing range. Thousands of live shells and mines are
spread out over the phosphorite waiting to explode
when even slightly disturbed. The deposit has been thoroughly studied by
scientists of many specialties, and all have concluded the risk is so great
that this will remain, possibly forever, a lost treasure in the sea. Several
people were heard to comment, as they walked away from all these riches, that
such are “the fortunes of war.”