The document outlines key concepts about biogeochemical cycles. It discusses the water cycle, carbon cycle, nitrogen cycle, and phosphorus cycle. For each cycle, it identifies the major steps, including evaporation, condensation, precipitation, runoff, percolation, transpiration, photosynthesis, cellular respiration, nitrogen fixation, nitrification, denitrification, assimilation, ammonification, and decomposition. It emphasizes that these cycles are essential for recycling critical elements like carbon, oxygen, nitrogen, water, and phosphorus that all living organisms depend on.

1. OBJECTIVES
• Summarize the steps of the water cycle in a diagram.
• Explain how carbon and oxygen are cycled through an
ecosystem.
• Describe why nitrogen must cycle through an
ecosystem.
• Summarize the 3 major conversions of nitrogen in
ecosystems.
• Explain why it is important that phosphorus be cycled
through an ecosystem.

2. VOCABULARY
• Carbon Cycle
• Respiration
• Nitrogen cycle
• Phosphorus cycle

3. NUTRIENT CYCLES: OBJECTIVES
• Summarize the steps of the water cycle in a diagram.
• Explain how carbon and oxygen are cycled through an
ecosystem in the carbon cycle.
• Define the steps in the nitrogen cycle.
• Summarize the 3 major conversions of nitrogen in the
nitrogen cycle.
• Be able to define the steps and know how one step impacts
the other.
• Be able to predict the outcome if one step of a cycle is
manipulated (products are removed or skipped).
• Do:
• Complete the packet in groups. This is your information gathering.
Complete by next class.
• Complete the cycles handout. This is also due next class.

4. CYCLES
• Just as organisms are interconnected to each other they
are connected to the physical environment as well.
• Name several examples of non-living things that
organisms, such as yourself, require to live.
• Oxygen, water, carbon, nitrogen, and phosphorus are a
few examples of these that we will discuss in this
section.
• Not what roles they play though. We already talked
about that in the previous chapter.
• You will learn how these substances cycle through the
ecosystems so that they may maintain their availability to
living organisms.

5. CYCLES IN NATURE
• Biogeochemical cycles = Cycles in which water
and minerals are recycled and reused by moving
from the non-living portion of the environment
into living things and back again.
• Water Cycle
• Carbon Cycle
• Nitrogen Cycle

6. WATER CYCLE
• The water cycle continuously moves water between the
atmosphere, the land, and the oceans.
• We see it first hand in several forms.
• Rain falls and is soaked up by the ground, or it pools
where it’s drank, or it is absorbed by plants, or it will sit
and evaporate back up into the atmosphere.
• Since it’s a cycle there is no starting point.
• We’ll start with water forming in the atmosphere.

7. IN THE MARGIN OF YOUR NOTES, IDENTIFY THE STEPS NUMBERED 1-6.
Condensation

8. At any moment, the atmosphere contains an astounding 37.5 million billion
gallons of water, in the invisible vapor phase. This is enough water to cover
the entire surface of the Earth (land and ocean) with one inch of rain.
http://whyfiles.org/2010/how-much-water-is-in-the-atmosphere/
• First, water vapor condenses in the cool air of the sky
into the clouds we see.
• Even if there’s no clouds there is still plenty of water
there.
CONDENSATION

9. • When enough water accumulates in the atmosphere it
collects a water droplets, gets heavy, and falls back to
Earth.
• This, what we call rain, is also known as precipitation.
PRECIPITATION

10. Some of this
water
percolates, or
is absorbed or
soaked into
the soil and
becomes
groundwater.
• Other water, called
runoff, flows and
accumulates
across the surface
of Earth and runs
into rivers, lakes,
and oceans.
RUN OFF & PERCOLATION

11. • Once here if not consumed, the water is heated by
the sun and reenters the atmosphere as water vapor
by evaporation.
• Water also evaporates from trees and plants in a
process called transpiration (& animals in
perspiration…sweating).
TRANSPIRATION & EVAPORATION

12. IN THE MARGIN OF YOUR NOTES, IDENTIFY THE STEPS NUMBERED 1-6.
Condensation
1
3
2
4
5
4
6

13. NITROGEN CYCLE
• Nitrogen, another essential element, must also be cycled.
• The atmosphere is about 78% nitrogen gas, N2. But most
organisms cannot use nitrogen gas.
• The nitrogen cycle is all about getting the nitrogen in the
atmosphere into forms that can be used by organisms.
• Recall, Nitrogen is used for
• The amino acids of proteins.
• In the nitrogenous bases of DNA & RNA
• The nitrogen cycle is the process in which nitrogen circulates
among the air, soil, water, and organisms in an ecosystem.

14. • Nitrogen-fixing bacteria live in
the soil and on the roots of
some plants.
• In a process called nitrogen fixation,
bacteria convert nitrogen gas, N2, into
ammonia, NH3.
• N2  Nitrogen Fixation (Bacteria)  NH3
NITROGEN CYCLE
How atmospheric
nitrogen gets into
the soil so it can be
accessed by living
things.

15. • During
ammonification,
nitrogen from
animal waste or
decaying bodies is
returned to the soil
as ammonia by
bacteria and
decomposers.
NITROGEN CYCLE
How atmospheric
nitrogen gets into
the soil so it can be
accessed by living
things.

16. • During nitrification,
ammonia, NH3, is
converted to nitrite
and then nitrate
NO3.
• Try not to confuse this
with nitrogen fixation.
NITROGEN CYCLE

17. • Assimilation is the
process in which plants
absorb nitrogen. When
an animal eats a plant,
nitrogen compounds
become part of the
animal’s body.
NITROGEN CYCLE
Forms of
nitrogen that
can be
accessed by
living things

18. • During denitrification, nitrate,
NO3, is changed to nitrogen
gas, N2, which returns to the
atmosphere.
NITROGEN CYCLE

19. NITROGEN CYCLE: ON YOUR HANDOUTS,
LABEL THE PARTS OF THE CYCLE.

20. NITROGEN CYCLE

21. NITROGEN CYCLE: MACRO PERSPECTIVE
Ammonification
Nitrogen fixation
Nitrification
Denitrification
Assimilation

22. CARBON AND OXYGEN CYCLES
• Carbon and oxygen are critical for life on Earth, and their
cycles are tied closely together.
• Just as with water, these are both cycled so organisms
always have a supply available.
• The carbon cycle is the continuous movement of
carbon from the nonliving environment into living things
and back.

23. • Starting with atmospheric carbon
dioxide, the carbon cycle begins
with plants and other autotrophs
absorbing CO2 and converting into
usable sugars and starches.
• This process is known as
photosynthesis.
THE CARBON CYCLE

24. • Animals then eat this
vegetation.
• They break down the
sugars & starches
made by plants and
covert it into ATP, the
energy of metabolism.
• In the process, they
release CO2 back into
the atmosphere.
• This process is called
cellular respiration.
THE CARBON CYCLE

25. • All life, plants, animals & everything else, eventually dies.
• When it does it is broken down , decays, and collects as
fossil fuels.
• Fossil fuels, like oil
and gasoline,
accumulate after
millions of years of
this process of
death and decay.
THE CARBON CYCLE

26. THE CARBON CYCLE
• The burning of this fuel,
called combustion, also
releases carbon dioxide
back into the atmosphere.

27. THE CARBON CYCLE: ON YOUR HANDOUTS,
LABEL THE PARTS OF THE CYCLE.

28. THE CARBON CYCLE

29. THE
CARBON
CYCLE
COMBUSTION
Man also plays
a role.
We are
responsible for
burning fossil
fuels, eating,
releasing
carbon dioxide,
and dying.
These all
contribute to the
cycling of
carbon.

30. CONCEPTS SUMMARY
• These are the things you have been exposed to and
need to know:
1. What is the difference between food chains and food
webs.
2. Why energy is lost in a food chain.
3. The 3 main cycles of matter.
4. Why they are important.
5. What are the steps in the cycles.

31. 1. Which of the following organisms
can transform light energy into
chemical energy?
A. organism 1
B. organism 4
C. organism 7
D. organism 9
2. If a disease killed off all of organism
2, which of the following organisms
would be most affected?
A. organism 3
B. organism 7
C. organism 8
D. organism 9
ANSWERS
3.. During which of the following months is the rate of
photosynthesis greatest?
A. May
B. March
C. January
D. September
4. If the data were obtained from the atmosphere over an
evergreen forest, the curve likely would
A. rise from February to May and fall from August to November.
B. vary less throughout the year.
C. rise steadily from January to December.
D. fall steadily from January to December.
5. If the y-axis of a graph displayed the rate of transpiration of a
deciduous forest, the curve likely would
A. rise from February to May and fall from August to November.
B. vary little throughout the year.
C. rise steadily from January to December.
D. fall steadily from January to December.

32. PHOSPHORUS CYCLE
• Phosphorus is often found in soil and rock as calcium
phosphate, which dissolves in water to form phosphate.
• The roots of plants absorb phosphate. Humans and
animals that eat the plants reuse the organic
phosphorus.
• When the humans and animals die, phosphorus is
returned to the soil.

33. PHOSPHORUS CYCLE
• Like water, carbon, oxygen, and nitrogen, phosphorus must be cycled in
order for an ecosystem to support life.
• Remember, phosphorus is an important element in ATP and DNA.
• It must cycle just like the other molecules.
• The phosphorus cycle is the movement of phosphorus in
different chemical forms from the surroundings to organisms
and then back to the surroundings.

34. THE PHOSPHORUS CYCLE