LECTURE OF zoogeography and paleontology.

1. HYDROSPHERE
TOPIC INSTRUCTOR: SAMMAN TANVEER

2. Content:
• Introduction
• Origin of water on earth
• Theories
• Water cycle
• Water contents
• Role and importance

3. Hydrosphere
• It comes from the
ancient Greek “hydro”
which means water and
“sphaira” which means
sphere.
• It refers to water on,
under, and over the
surface of the Earth.

4. Origin of water on earth?
• When earth first formed it
was so hot that the original
water would be lost to
space.
• Water is added later by
comets and or asteroids.
• Some water (H2+O) from
the protoplanetary disk and
some water formed or
originated in the solar
nebula.

5. Asteroids and Comets
• An asteroid is a rocky object
that orbits the Sun. Asteroids
are smaller than a planet, but
they are larger than the
pebble-size objects we call
meteoroids.
• Comets are small icy dirtballs
that orbit the Sun; comets are
made of ice and dust while
asteroids are made of rock

6. Theories about origin of water
• Around 4.5 billion years ago, molten earth began to cool. Violent
collisions with comets and asteroids brought the fluid of life - water - and
the clouds and oceans began to take shape.
• It wasn't until a billion years later that the first life was brought forth,
filling the atmosphere with oxygen.
1. Degasification theory
• Water vapor, CO2, CO, CH, Ammonia, sulfur, HCl, argon, and Hydrogen
came to Earth during lava degasification resulting in Water.
• Acid rains to underlying water results to alkali Earth.

7. 2. Collision with comets:
• 4-40% of water.
• Glaciation
• Lower H2O level
• Mountains, ice
• Vegetation
• Oceans >size
• H2O cycle
• Photosynthesis
• 500 million km2

8. Water cycle:
• There is always the same
amount of water on Earth.
• Water appears in different
states (liquid, gas, or solid
form).
• Water continually moves
between the atmosphere, the
oceans, and the continents.

9. This continual movement is called the water cycle:
1. Evaporation:
Water evaporates into the atmosphere, where it cools.
2. Condensation:
As it gets cooler in the atmosphere, it condenses and forms clouds.
3. Precipitation:
When clouds cannot absorb any more water there is precipitation in the
form of rain, snow, or hail. Some precipitation falls on the land flowing
into lakes and rivers, and other water filters into the ground becoming
groundwater.
4. Transportation:
Water in rivers or groundwater is transported to the oceans and seas
again and the water cycle begins again.

12. Distribution of water on earth
Volume Percent of Total
OCEANS 1,350 x 1015 m3 97.3%
CRYOSPHERE
(Glaciers & Polar Ice)
29 x 1015 m3 2.1%
UNDERGROUND
(Aquifers)
8.4 x 1015 m3 0.6%
LAKES & RIVERS 0.2 x 1015 m3 0.01%
ATMOSPHERE 0.013 x 1015 m3 0.001%
BIOSPHERE 0.0006 x 1015 m3 4 x 10-5%

15. Water can be found in:
• Oceans: vast masses of saltwater that separate the
continents.
• Seas: oceanic waters that are close to continents and not
as deep as oceans.
• Rivers: continuously flowing currents of water that flow
into seas, lakes, and other rivers.
• Tributary: a river that flows into another river.

16. OCEAN SEAS
RIVER TRIBUTARY

17. • Groundwater: rainwater
that infiltrates rocks and soil
into the Earth’s surface.
• Aquifers: stores of ground
water that accumulate
underground on top of
impermeable layers of rock.
• Wells: holes that men do
into the Earth’s surface to
bring underground water to
the surface.

18. • Glaciers: a huge mass of ice,
formed from compacted snow,
slowly flowing over a land
mass.
• Ice caps: a huge mass of ice
and snow that permanently
cover the poles of the Earth.
• Lakes: large bodies of water
that accumulate in inland
basins. They receive water
from rivers, precipitation and
groundwater

19. Role of Hydrosphere
• Significance of water in cells. Every cell in a living organism is
composed of around 75% of water, thus, it enables the cell for
functioning appropriately. ...
• Human needs water, Human beings make use of water in various
ways.
• Water offers habitat.
• Regulate climate.

20. The major importance of
the hydrosphere is that water
sustains various life forms
and plays an important role
in ecosystems and regulating
the atmosphere.