Download AP Chapter 5 Notes

Chapter 5
The Biogeochemical Cycles
Botkin & Keller
Environmental Science 5e
How Chemicals Cycle
•
Biogeochemical Cycle
– The complete path a chemical takes through
the four major components – or reservoirs –
of Earth’s systems
1.
2.
3.
4.
Atmosphere
Hydrosphere
Lithosphere
Biosphere
Botkin & Keller
Environmental Science 5e
Botkin & Keller
Environmental Science 5e
© 2008 John Wiley and Sons Publishers
Biogeochemical Cycles and Life:
Limiting Factors
• Macronutrients
– Elements required in large amounts by all life
– Include the “big six” elements that form the fundamental building
blocks of life:
• Carbon, oxygen, hydrogen, phosphorus, nitrogen, sulfur
(CHNOPS!)
• Micronutrients
– Elements required either in
• small amounts by all life or
• moderate amounts by some forms of life and not all by others
• Limiting factor
– When chemical elements are not available at the right times, in
the right amounts, and in the right concentrations relative to each
other
Botkin & Keller
Environmental Science 5e
The Geologic Cycle
• The Geologic Cycle:
– The processes responsible for formation and
change of Earth materials
– Best described as a group of cycles:
•
•
•
•
Tectonic
Hydrologic
Rock
Biochemical
Botkin & Keller
Environmental Science 5e
Botkin & Keller
Environmental Science 5e
© 2008 John Wiley and Sons Publishers
Tectonic Cycle
• Tectonic cycle:
– Involves creation and destruction of the solid
outer layer of Earth, the lithosphere
• Plate tectonics:
– The slow movement of these large segments
of Earth’s outermost rock shell
– Boundaries between plates are geologically
active areas
Botkin & Keller
Environmental Science 5e
Botkin & Keller
Environmental Science 5e
© 2008 John Wiley and Sons Publishers
Tectonic Cycle: Plate Boundaries
• Divergent plate boundary:
– Occurs at a spreading ocean ridge, where plates are
moving away from one another
– New lithosphere is produced (seafloor spreading)
• Convergent plate boundary
– Occurs when plates collide
• Produces mountain ranges
• Transform fault boundary
– Occurs where one plate slides past another
• San Andreas Fault in California
Botkin & Keller
Environmental Science 5e
The Hydrologic Cycle
• The Hydrologic Cycle:
– The transfer of water from the oceans to the
atmosphere to the land and back to the
oceans. Includes:
•
•
•
•
Evaporation of water from the oceans
Precipitation on land
Evaporation from land
Runoff from streams, rivers, and sub-surface
groundwater
Botkin & Keller
Environmental Science 5e
Botkin & Keller
Environmental Science 5e
© 2008 John Wiley and Sons Publishers
The Rock Cycle
• The rock cycle:
– Numerous processes that produce rocks and
soils
– Rock is classified as
• Igneous
• Sedimentary
• Metamorphic
Botkin & Keller
Environmental Science 5e
Botkin & Keller
Environmental Science 5e
© 2008 John Wiley and Sons Publishers
The Carbon Cycle
• Carbon is the element that anchors all
organic substances
• The carbon cycle:
– C combines with and is chemically and
biologically linked with the cycles of O and H
that form the major compounds of life
Botkin & Keller
Environmental Science 5e
Botkin & Keller
Environmental Science 5e
© 2008 John Wiley and Sons Publishers
Botkin & Keller
Environmental Science 5e
© 2008 John Wiley and Sons Publishers
Botkin & Keller
Environmental Science 5e
© 2008 John Wiley and Sons Publishers
The Nitrogen Cycle
• The nitrogen cycle:
– Cycle responsible for moving N components through
Earth’s systems
– Extremely important because N is required by all
living things
• Nitrogen fixation:
– The process of converting molecular nitrogen (N2) in
the atmosphere to ammonium (NH4+) or nitrate (NO3-)
– Caused by lightning, soil bacteria, extreme heat
(industry)
• Denitrification:
– The process of releasing fixed nitrogen back to
molecular nitrogen (done by bacteria)
Botkin & Keller
Environmental Science 5e
Botkin & Keller
Environmental Science 5e
© 2008 John Wiley and Sons Publishers
The Phosphorus Cycle
• The phosphorus cycle:
– Involves the movement of P throughout the
biosphere and lithosphere
– Important because P is an essential element
for life and often is a limiting nutrient for
plant growth.
Botkin & Keller
Environmental Science 5e
Botkin & Keller
Environmental Science 5e
© 2008 John Wiley and Sons Publishers