CHAPTER 15

pages 10-16

David Bayles

Kristy Galarza

Sahily Acosta

Melisabet Acosta

Nicole

Salt and Minerals

Many of the mineral resources come from terrestrial sources, However many come from

the ocean.

These Minerals are

Ferromanganese Nodules- Commonly found around shark teeth and volcanic fragments.

Nodules form in all oceans. The richest nodule deposit is in the Pacific Ocean. These can

be made from copper, nickel and cobalt. This is very useful to the U.S. armed forces.

Magnesium compounds- A strong light weight metal. Is essential for aerospace

construction and other structural applications. Burns intensely, which can be used for flairs

and other hot combustion. Most of this production comes from seawater. This is the third

most abundant element in seawater.

Salt and minerals cont…

Salts- Mostly contains sodium chloride, but also calcium carbonate, gypsum and other rich

compounds. Made by seawater being evaporated. Is also used in the production of

fertilizer, medicines, wallboards and other building materials and table salt.

Phosphorite- These are the remains of the dead marine organisms. Extensive deposits off

the coast of South American Pacific coasts, California, Florida and African oceans. This is

important to all ecosystems due to it being able to fertilize. Also used as a small economic

exploit.

Marine Muds and Metals- These can include lead, zinc, copper, iron, sliver, ext. These

minerals are placed where geothermal heat reaches the seabed's. These then create a

potential source for minerals and metals.

Question 6

What resource do we get from seawater? What products are they used for?

The resources we get from seawater are Ferromanganese Nodules, Magnesium

compounds, Salts, Phosphorite, and Marine Muds and Metals. They can be used for

different metals and also used for building common walls, flares, table salt and other

common uses.

Phosphorite

Phosphorite deposits are the remains of marine organisms that live in areas with extensive

upwelling.

The phosphorus in these organisms remains in phosphorite form when the creatures die.

Extensive deposits exist off the coasts of the South American Pacific coast, California,

Florida, and the African Atlantic coast. Major accumulations of phosphorite are found

primarily in a depth range of about 30 to 300 meters.

Phosphorite cont…

Phosphorus is important for all life, phosphorite is important in fertilizers used for agriculture.

However much as ferromanganese nodules remain too costly to recover, offshore

phosphorite deposits are currently uneconomical to exploit.

Question 7

What is phosphorite and what is it used for? Why will terrestrial sources be the primary sources

for phosphorite?

Phosphorite deposits are the remains of marine organisms that live in areas with extensive

upwelling. Phosphorus is important for all life, phosphorite is important in fertilizers used for

agriculture. 150 million tons of phosphate rock mined annually come from terrestrial

sources, which will probably continue for the foreseeable future. Theres no substiture for

phosphorus in living systems, and terrestrial reserves may be depleted by the mid 21st

century.

Hydrothermal vents

Hydrothermal vents are home to some of the most unique biological communities on our

planet. Their productivity is not based on photosynthesis . Instead, they use the rich array

of chemicals, primarily sulfides, emanating from deep within the Earth in a process called

chemosynthesis.

A hydrothermal vent is a opening in a planet's surface from which geothermally heated

water issues. Hydrothermal vents are commonly found near volcanically active places,

areas where tectonic plates are moving apart, ocean basins, and hotspots.

Hydrothermal vents cont…

Mineral sources also exist in places where geothermal heat reaches the seabed.

For example in the Red sea, this process causes metals and other dissolved compounds to

precipitate into basins on the bottom. These hot brines produce muds rich in metal

sulfides, silicate and other oxides in a high enough concentration.

When the heated water cools in the cold deep sea water these precipitate into mounds

and chimneys around the vents . This creates a potential source for these minerals and

metals.

Question 8

What potential resources exist at hydrothermal vents and in marine muds? Explain which of

these resources is a strategic metal and why.

Hydrothermal vents support chemosynthetic ecosystems and maintain seawater

chemistry. They carry large quantities of metals and minerals such as lead, zinc, copper,

iron, silver, cadmium, and sulfur.

Marine muds produce rich in metal sulfides, silicate, and other oxides in a high enough

concentration to make recovering them economically feasible.

Gravel and Sand

Sand are gravel are important marine resources. At present, they are second only to gas

and oil in there annual economic value. Without sand and gravel to make concrete,

modern construction would be impossible. Other industries use sand rich in calcium

carbonate to make glass as an animal feed additive, and to reduce soil acidity.

Gravel and sand cont…

To meet this need, each year industry mines more than one billion metric tons of sand and

gravel from offshore deposits. Most of these deposits are considered nonrenewable relict

deposits.

The importance of offshore sand and gravel varies by region. Although about 99% of the

worlds sand and gravel comes from terrestrial sources, offshore sources account for

significantly more in some nations that have better access to marine sources than

terrestrial sources.

Question 9

What physical marine resources are second only to gas and oil in terms of their annual

economic value?

sand and gravel are second only to gas and oil in their annual economic value because

without them modern construction would be impossible.

Energy

The sea offers renewable energy options. Since it rises and falls with waves and tides and

captures heat from the sun, the sea provides several types of renewable energy for

human use.

Energy cont…

There are many ways to capture wave energy with at least two methods in use.

1. involves building a caisson. The opening under water permits rising waves to compress the

air in electricity. When the wave passes, the water level in the chamber drops, drawing air

back in.

2. Another involves a series of buoys attached by vertical rods to the sides of a wheel. As the

buoys rise and fall in the waves they crank the wheel in a circle. An axle attached to the

when turns a generator to produce electricity.

3. Tide can be used for energy where the tidal changes in 3 meters or more. To generate

power, engineers build barriers, which act like two-way damns, across bays or tidal rivers.

When the tide rises the water spins turbine generators as it flows into the bay. After the tide

changes the water generates power again as the flow returns to the sea.

Question 10

Describe three ways the ocean can supply renewable energy. Which of these has proved

most practical? Why?

Of these three renewable energies (tide, building a caisson, and a series of buoys), none

are commercially feasible at present. Tidal power seems to be the most feasible . Using

tidal energy has widespread environmental concerns that include ecological damage

caused by the massive dams and changes in the flow of nutrients to and from bays and

tidal rivers. Thermal gradient has been tried experimentally but has largely been

abandoned because it has low efficiency.