I'm impressed that you know what phytoplankton
are! Most people do not. I study phytoplankton, so
I'm glad to hear that you know what phytoplankton
are and that you know one of the reasons why
phytoplankton are so important to the earth.
The answer to your question is really easy, so
I'm not going to come right out and tell you.
You'll probably laugh when you figure it out. The
main way oxygen is added to the earth's atmosphere
is though photosynthesis. The main way it is taken
out or removed is through respiration. During
photosynthesis (photo = light, synthesis = to
make), energy from sunlight is captured with
special light-absorbing chemicals (called
pigments) and this captured energy is used
to make living tissue from the carbon molecules in
carbon dioxide gas. Oxygen is released almost as a
waste product. In respiration, the reverse occurs:
the carbon molecules used to make new living
tissue are taken from food. The energy for
respiration comes from food and oxygen instead of
sunlight, and carbon dioxide gas is released as a
waste product. Which process do humans use to
grow: photosynthesis or respiration?
Phytoplankton are one group of organisms
that use photosynthesis to grow. Phytoplankton
live in the water. There are other organisms that
live on land that use photosynthesis to grow.
Pigments, or light-absorbing chemicals, come in
many colors but the main ones used in
photosynthesis are called chlorophylls.
Living tissue with a lot of chlorophyll looks
If you want to know what organisms are
providing the other 50% of oxygen to the earth's
atmosphere, walk outside and look for living
organisms that are green!