Transcript Day 4 - Ch.5(21)Cycles

Chapter 5
Ecosystems
and the
Physical
Environment
The Gaia Theory
Dynamic Equilibrium
Negative Feedback
Positive Feedback
The Gaia Theory: The
organic and inorganic
components of Planet Earth
have evolved together as a
single living, self-regulating
system.
In a phrase, “life maintains
conditions suitable for its
own survival.”
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
Cycles
Carbon
1. Lipids
2. Nucleic Acids
3. Carbohydrates
4. Amino Acids
Nitrogen
1. Amino Acids
Phosphorus
1. ATP
2. DNA
3. Cell Membranes
Sulfur
1. Amino Acids
2. Keratin
Fixed amounts of all elements on earth
* Oxidation describes the loss of electrons by a molecule, atom or ion
* Reduction describes the gain of electrons by a molecule, atom or ion
Carbon Cycle
Billions of Tons
http://www.youtube.com/watch?v=
0Vwa6qtEih8&feature=related
Carbon Silicate
A weathering Cycle:
1.Atmospheric CO2 forms H2CO3 (Carbonic Acid) precipitation which moves through soil
2.H2CO3 dissociates & forms H+ & HCO -3 (bicarbonate)
3.Silicate rich minerals interact with the free H+ to release Ca2+
4.Shellfish
5.Subduction – silicate formation at temperatures above 300 °C
Carbon Silicate
Believed to provide important negative
feedback mechanisms that control the
temperature of the atmosphere.
Nitrogen cycle
Nitrogen cycle:
Biological
nitrogen
1. fixation
Lightning
Volcanoes
Bacteria
(Ammonia)
NH3 &
NH4-
Atmospheric
nitrogen (N2)
Nitrogen
fixation by
humans
Decomposition - urea
5.Denitrification
4. Ammonification
Plant & animal
proteins
Internal
cycling
3. Assimilation
(Oxidation)
2. Nitrification
NO3-
(Nitrates &
Nitrites)
Nitrogen Cycle & Steps
1. Nitrogen Fixation is the conversion of elemental
nitrogen(N2) to organic ammonia(NH3) by bacteria,
lightning, industry, volcanoes.
2. Nitrification - conversion of ammonia or ammonium
(NH4) into nitrites(NO-2) and then into nitrates (NO-3)
3. Assimilation- plants absorb nitrates or ammonia
4. Ammonification - nitrogen is converted into ammonia
from animal waste or dead organisms by aerobic bacteria
5. Denitrification - anaerobic bacteria convert nitrates &
nitrites to nitrogen gasses off to atmosphere
1. Nitrogen is not a reactive molecule
2. 78% atmosphere N2 & 21% oxygen & .038% CO2
YouTube: http://www.youtube.com/watch?v=m4YToXw724w&feature=related
Phosphorus Cycle
Does not include the atmosphere
YouTube:
http://www.youtube.com/watch?v=RKkC2JpjaGc&feature=related
Phosphorus Cycle
Phosphorus
Brazil
Guano
Accelerated Eutrophication
Cycling of Materials within Ecosystems
Sulfur cycle:
YouTube:
http://www.youtube.co
m/watch?v=BzPeA9oQ
Nl8
Cycling of Materials within Ecosystems
Hydrologic cycle:
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 (7 plates)
Boundaries between plates are geologically
active areas
Internal Planetary Processes
Volcanic Activity 2011
Internal Planetary Processes
Plate boundaries
Internal Planetary Processes
Plate boundaries
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 linear coastal mountain ranges or continental
mountain ranges
Transform fault boundary
Occurs where one plate slides past another
San Andreas Fault in California
Internal Planetary Processes
Volcanoes
Most volcanoes occur
along subduction zones
Internal Planetary Processes
Volcanoes
Some occur along
spreading zones
Few, such as Hawaiian
Islands, not associated
with plates.
Internal Planetary Processes
Earthquakes
• caused by release of built up stress,
typically along faults
• movement releases seismic waves
Typical side effects include:
1) Landslides
2) Tsunamis