the
Hydrosphere
What is the
Hydrosphere?
The hydrosphere is all of the
water on Earth. Oceans, lakes,
rivers, wells, clouds, fog and
icebergs are all part of the
hydrosphere. You may have
noticed that not all of these water
sources are in the liquid state.
Water vapor and ice are also part
of the hydrosphere. Ice in the
hydrosphere has a special name;
it’s called the cryosphere.
2020 © Kelsey Burkman
Our planet is over 75% water,
making it appear blue from space.
Because of its blue appearance,
Earth earned its nickname, The
Blue Planet. The abundance of
liquid water on Earth differentiates
it from other planets.
The Water Cycle
Parts of Earth’s hydrosphere
work together to form the water
cycle. The water cycle is how water
is cycled through the four spheres.
Water from Earth’s surface
evaporates into the atmosphere,
forming clouds (water vapor). The
water vapor then cools and
condenses, eventually falling back
to the earth’s surface as rain or
snow. Then, the cycle starts all over
again! The water cycle is largely
responsible for life on Earth.
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The Ocean
The ocean accounts for 97%
of all water on Earth. What’s more,
the ocean covers 70% of Earth’s
surface! The ocean makes life on
Earth possible because of its role in
the water cycle and the climate.
Climate refers to trends in weather
conditions in a given area over
time. When the sun warms the
ocean water, the ocean transfers
heat to the atmosphere. The
atmosphere then carries this heat
around the globe, regulating
temperatures. Without the ocean
to regulate global temperatures,
Earth would be too cold to sustain
life!
2020 © Kelsey Burkman
Ocean Life
Y
The ocean is brimming with life.
There are hundreds of thousands of
species who call the ocean home.
Some of these species are
microscopic, or too small to be
seen, like plankton. On the other
hand, the ocean is also home to
some massive animals. The blue
whale is the largest species to have
ever lived on Earth.
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Phytoplankton
Although we cannot see the
microscopic organisms living in
the ocean, they are vital to
marine ecosystems. One example
of these microscopic organisms is
phytoplankton. Phytoplankton is
basically a microscopic plant or
algae that uses photosynthesis to
create food from the sunlight.
Many organisms, such as shrimp
and fish, feed on phytoplankton.
Larger fish, whales, birds and
humans then eat shrimp and fish.
In this way, phytoplankton play a
large role in sustaining the ocean
food web. If you eat seafood, you
have eaten phytoplankton!
Humans and the
Ocean
Human beings have relied
on the ocean for resources for
their entire existence. Not only
does the ocean provide a
source of food, but it is also a
route for trade and
exploration. Today, people still
rely on the ocean for travel
and food, such as fish and
shellfish. Additionally, most of
the world’s machinery, grains
and oil are carried by ship
across the globe.
2020 © Kelsey Burkman
Port of Valparaíso
Valparaíso, Chile
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