Lesson 18.
Biogeochemical Cycles
enumerate the different
Objectives biogeochemical processes
1 happening in the
At the end environment; and
of the
lesson, you describe the process
should be involved in each
able to:
2
biogeochemical cycle.
Learn about It!
Biogeochemical Cycle
● These cycles involve
physical and
biological processes
in the cycling of
important nutrients
such as water, carbon,
oxygen, nitrogen, and
phosphorus.
Cycle of process
Learn about It!
Biogeochemical Cycle
● These cycles do not only
provide constant supply of
nutrients within the
environment.
● Cycles also illustrate the
transition nutrient forms.
Cycle of process
Learn about It!
Water Cycle
1. Heat from the sun
evaporates liquid water
from oceans or land.
Water Cycle
Learn about It!
Water Cycle
2. Water vapor is also
released from plants, a
process called
transpiration.
Water Cycle
Learn about It!
Water Cycle
3. Water vapor reaches a
region of lower
temperatures and
condenses leading to
cloud formation.
Water Cycle
Learn about It!
Water Cycle
4. Liquid water is released
from the skies and back
to the lithosphere as rain
or snow through
precipitation.
Water Cycle
Learn about It!
Carbon-Oxygen Cycle
● Carbon and oxygen levels
interplay within the
ecosystem to form the
carbon-oxygen cycle.
● Its two main driving
forces are
photosynthesis and
cellular respiration. Carbon Cycle
Learn about It!
Carbon-Oxygen Cycle
● During photosynthesis,
water and carbon
dioxide is converted into
food, and oxygen is
released as a byproduct.
Carbon Cycle
Learn about It!
Carbon-Oxygen Cycle
● Organisms absorb
oxygen for respiration.
● Respiration produces
energy by converting
food into carbon dioxide.
Oxygen Cycle
Learn about It!
Nitrogen Cycle
● The nitrogen cycle has
three driving forces:
nitrogen fixation,
nitrification, and
denitrification.
Nitrogen Cycle
Learn about It!
Nitrogen Cycle
● Nitrogen enters an
ecosystem through
nitrogen fixation.
● This is when nitrogen gas
is converted to its usable
form, ammonia (NH3).
Nitrogen Cycle
Learn about It!
Nitrogen Cycle
● Nitrogen compounds are
also converted into
ammonia by
decomposers.
● Ammonia is then
converted to nitrites and
nitrates by a process
called nitrification. Nitrogen Cycle
Learn about It!
Nitrogen Cycle
● Nitrates and nitrites are
forms of nitrogen plants
can use.
● When animals feed on
plants, they also acquire
nitrogen compounds.
Nitrogen Cycle
Learn about It!
Nitrogen Cycle
● Nitrates can be converted
back to nitrogen gas
through denitrification,
completing the cycle.
Nitrogen Cycle
Learn about It!
Phosphorus Cycle
● The recycling of
phosphorus is localized in
ecosystems because
phosphates are bound to
soil particles.
● It barely moves through
the atmosphere.
Phosphorus Cycle
Learn about It!
Phosphorus Cycle
● The main processes that
gradually add phosphates
to soil are rock
weathering and the
decomposition
Phosphorus Cycle
Key Points
The processes that drive the water cycle are
1 evaporation, condensation, and precipitation.
Carbon and oxygen levels interplay within the
ecosystem to form the carbon-oxygen cycle. Its two
2 main driving forces are photosynthesis and cellular
respiration.
Key Points
The nitrogen cycle has three driving forces: nitrogen
3 fixation, nitrification, and denitrification.
The recycling of phosphorus is localized in
4 ecosystems because phosphates are bound to soil
particles. It barely moves through the atmosphere.
Check Your Understanding
Write true if the given statement is correct and
false if otherwise.
1.The water cycle is dependent on the evaporation of the
groundwater.
2.The carbon cycle is essential to avoid global warming
3.The nitrogen cycle is important for the growth of the
plants.
4.The phosphorus cycle mainly happens in the ocean.
5.The plants play important role in the oxygen cycle.
Challenge Yourself
Which part of the
carbon cycle can be
modified to avoid
global warming on
Earth?
Bibliography
Carnegie Mellon University. “Oxygen Cycle.” Accessed August 31, 2017.
http://environ.andrew.cmu.edu/m3/s4/cycleOxygen.shtml
Department of Environment and Natural Resources. “National Greening Program.” Accessed
September 1, 2017. https://www.denr.gov.ph/priority-programs/national-greening-
program.html
Elmhurst College. “Phosphorus Cycle.” Accessed August 30, 2017.
http://chemistry.elmhurst.edu/vchembook/308phosphorus.html
Joan Fong, et al. 2014. Science Matters. Second Edition. Singapore: Marshall Cavendish Education.
Jane B. Reese, et al. 2011. Campbell Biology. Ninth Edition. San Francisco CA: Pearson Education, Inc. /
Pearson Benjamin Cummings
Bibliography
Lam, Peng Kwan and Erik Y K Lam. 2007. Biology Matters. First Edition. Singapore: Marshall Cavendish
Education.
Langston University Research & Extension. “Ecosystems, Energy and Production.” Accessed August 29,
2017. http://www2.luresext.edu/aquaculture/Limnology%20lectures/chap%205%20ecosystems.pdf
