The hydrosphere is the liquid water
component of the Earth. It includes
the oceans, seas, lakes, ponds, rivers
and streams. The hydrosphere
covers about 70% of the surface of
the Earth and is the home for many
plants and animals.
• Water is found in many places on Earth including
on the surface of the planet, within rocks below
the surface, and in the atmosphere.
• Water travels between different areas of the
Earth through the water cycle.
• About 70% of the Earth surface is covered with
water, and most of that is the ocean.
• Only a small portion of the Earth's water is
freshwater, which is found in rivers, lakes, and
• In addition to liquid water, water is also present
on Earth in the form of ice.
4. • The hydrosphere, like the atmosphere, is always
• The motion of rivers and streams can be easily
seen, while the motion of the water within lakes
and ponds is less obvious.
• These types of motions are in the form of
currents that move the warm waters in the
tropics toward the poles, and colder water from
the polar regions toward the tropics.
• These currents exist on the surface of the ocean
and at great depths in the ocean (up to about
5. • The characteristics of the ocean which affects its
motion are its temperature and salinity.
• Warm water is less dense or lighter and
therefore tends to move up toward the
surface, while colder water is more dense or
heavier and therefore tends to sink toward the
• Salty water is also more dense or heavier and
thus tends to sink, while fresh or less salty water
is less dense or lighter and thus tends to rise
toward the surface.
• The combination of the water's temperature and
salinity determines whether it rises to the
surface, sinks to the bottom or stays at some
6. • The oceans currents are also affected by the
motion of the atmosphere, or winds, above it.
• The energy in the wind gets transferred to the
ocean at the ocean surface affecting the
motion of the water there.
• The effect of wind is largest at the ocean
7. • The ocean serves two main purposes in the
• First, it is a large reservoir of chemicals that can
contribute to the greenhouse effect in the
atmosphere and absorbing 90% of the solar
radiation which hits the surface.
• This reservoir changes very slowly limiting how
fast the climate can change.
• Second, it works with the atmosphere to
redistribute the energy received from the sun
such that the heat in the topics, is transferred
toward the poles, where heat is generally lost to
8. The continuous movement of water
into the air, onto land,
and then back to water sources is
known as the water cycle,
9. • Water moves through the hydrosphere in a
• Water collects in clouds, then falls to Earth in
the form of rain or snow.
• This water collects in rivers, lakes and oceans.
• Then it evaporates into the atmosphere to
start the cycle all over again
10. • evaporation is the process by which liquid water is
heated by the sun and then rises into the atmosphere
as water vapor.
• Water continually evaporates from Earth's
oceans, lakes, streams, and soil, but the majority of the
water evaporates from the oceans.
• In the process of condensation water vapor forms
water droplets on dust particles.
• These water droplets form clouds, in which the
droplets collide, stick together, and create
larger, heavier droplets.
• These larger droplets fall from clouds as rain in the
process called Precipitation may also take the form of
snow, sleet, or hail.
12. • This cycle consists of a group of reservoirs
containing water, the processes by which
water is transferred from one reservoir to
another (or transformed from one state to
another), and the rates of transfer associated
with such processes.
• These transfer paths penetrate the entire
hydrosphere, extending upward to about 15
kilometres in the Earth’s atmosphere and
downward to depths on the order of five
kilometres in its crust.
13. Reservoir volume (in millions of
percent of total
Oceans 1,370.0 97.25
ice caps and glaciers 29.0 2.05
(less than 750 metres)
Lakes 0.125 0.01
soil moisture 0.065 0.005
atmosphere** 0.013 0.001
Rivers 0.0017 0.0001
Biosphere 0.0006 0.00004
Total 1,408. 7 100
14. Ocean Water
The difference between ocean water and
fresh water is that ocean water contains
more salts. These salts have dissolved
out of rocks on land and have been carried
down rivers into the ocean over millions of
years. Underwater volcanic
eruptions also add salts to the ocean.
15. • most of the salt in the ocean is sodium chloride,
the same salt that we sprinkle on food.
• Sodium chloride,NaCl, is made up of the
elements sodium, Na,and chlorine, Cl.
• The average salinity of sea water is 3.5 percent by
• The salinity of ocean water is lower in places that
get a lot of rain or in places where fresh water
flows into the sea.
• Salinity is higher where water evaporates rapidly
and leaves the salts behind.
16. Fresh Water
• Most of the water on Earth is salt water in the ocean.
• A little more than 2 percent of all the water on Earth is
fresh water .
• Most of the fresh water is locked up in icecaps and
glaciers that are so large they are hard to imagine.
• For instance, the ice sheet that covers Antarctica is as
large as the United States and is up to 3 km thick.
• The rest of Earth’s fresh water is found in
lakes, rivers, wetlands, the soil, rock layers below the
surface, and in the atmosphere.
17. River Systems
• A river system is a network of streams that
drains an area of land.
• A river system contains all of the land drained
by a river, including the main river and all its
• Tributaries are smaller streams or rivers that
flow into larger ones.
• Rain and melting snow sink into the ground and
run off the land.
• Some of this water ends up in streams and
rivers, but most of it trickles down through the
ground and collects as groundwater.
• Groundwater fulfills the human need for fresh
drinking water and supplies water for many
agricultural and industrial uses.
• But groundwater accounts for less than 1 percent
of all the water on Earth.