Environmental Geography Chapter 4

1. GEOG 106
Ch. 4: Global Cycles
and Systems
pp. 49-66
29 Sep and 1 Oct
‘09

2. What Makes Earth Unique?
• Intermediate distance from the Sun:
– Approximately 150 million km (93 million mi),
• Average global surface temperature of 15˚C
(60˚F):
– Greenhouse effect of Earth’s atmosphere, and
• Water exists on Earth’s surface and
atmosphere in three physical states:
– Solid (ice), liquid, and gas (vapor).

3. Interactions among Earth’s
Spheres:
• Atmosphere,
• Biosphere,
• Hydrosphere, and
• Lithosphere.

4. • Lithosphere
– Litho, Greek for “stone”
• Atmosphere
– atmo, Greek for “air”
• Hydrosphere
– hydro, Greek for “water”
• Biosphere
– bio, Greek for “life”
L
A H
B
Interacting spheres
 The Environmental Spheres

5. Interrelationships among Earth’s Spheres:
Fig 4.1: Locations and relative densities of
Earth’s spheres.

6. Outgassing of the lithosphere into the atmosphere:
Fig. 4.2: Outgassing via volcanic activity. Volcanoes are
concentrated along plate boundaries.

7. Earth’s Crust:

8. Earth’s Interior:

9. Rock Cycle:

10. Geologic
Time:

11. Geologic Time:

12. Plate Tectonics:
• All forms of breaking and bending of the
entire lithosphere, including the crust.
• Includes convergent, divergent, and
transform interactions.
• Includes both folding and faulting.

13. Lithospheric Plates:

14. Lithospheric Plates:

15. Plate Boundary Interactions:

16. Plate Boundary Interactions:

17. Weathering, Mass Wasting, and Erosion:

18. Weathering:
Note that weathering increases surface area!

19. Physical Weathering:
• Ice/Frost
Wedging,
• Salt Wedging,
• Wave action,
and
• Root wedging.

20. Chemical Weathering:
• Oxidation,
• Carbonation,
• Hydration,
and
• Solution.
Carlsbad Caverns, New Mexico

21. Mass Wasting:
• Creep (slow),
• Solifluction (slow),
• Slumping and Earthflows (fast),
• Rock falls (fast) and Talus slopes,
• Landslides (fast), and
• Avalanches (fast).

22. Rock fall and Talus Slope:
Rock falls from here
Talus accumulates
here

23. Landslide
in
California:

24. Erosion:
• Water,
• Wind, and
• Ice (Glaciers).

25. Water Erosion:
Overland Flow and
Sheet Erosion
Rills and
Gullies
Gully in Iowa Farmland

26. Wind (Eolian) Erosion:
Star Dunes in the Namib Desert, Namibia

27. Glacial Erosion:
Alpine Glacier on Mt. Rainer, Washington

28.  The Hydrologic Cycle
• Introduction
– Series of storage areas of water in the hydrosphere
– Water moves between storage areas

29. • The Earth’s Hydrologic Cycle…

30.  The Oceans
• Four Oceans

31.  Composition of the Atmosphere
• Permanent
Gases
– Nitrogen and
oxygen
dominate

32. • Variable Gases
– Water Vapor
– Carbon Dioxide
– Ozone

33. Stable components of theStable components of the
atmosphere:atmosphere:
% by Volume% by Volume
7878
2121
~1~1
trace (0.036)trace (0.036)
Argon (Ar)Argon (Ar)
Gas (Symbol)Gas (Symbol)
CarbonCarbon
Dioxide(CODioxide(CO22))
Oxygen (OOxygen (O22))
Nitrogen (NNitrogen (N22))

34. Variable components:
• Water vapor (H2O)
• Ozone (03)
• Airborne particulates
• Greenhouse gases
– Carbon dioxide
– Methane
– Nitrous oxide
– CFCs and other halocarbons

35.  Vertical Structure
of the Atmosphere
• Temperature
– Thermal layers
– Troposphere
– Stratosphere
– Mesosphere
– Thermosphere
– Exosphere

36. • Troposphere
– Our weather
occurs here

37. The TroposphereThe Troposphere
• Almost all of our weather occurs in
this lowest layer.
• Comprises about 75 to 80% of the
mass of the atmosphere.
• Consists of about 78% N, 21% O2, and
less than 1% each of Ar, H20 vapor,
CO2, and other gases.

38. Fig. 4.3: The
total mass of
living matter
(biosphere) is
much less
than that of
air and water.
On land, life
ranges from a
few cm to 80
m deep, while
in water, the
average is
100m.
Distribution of Life, Water, and Air:

39. Distribution of Life in the Ocean:
Fig. 4.4: Most
marine life is
concentrated in the
photic zone. Life is
abundant on
continental shelves
and littoral zones.
Within the deep,
abyssal plains, there
is too little light to
support much life.
Terrestrial
environments
comprise 29 percent
and aquatic 71
percent.

40. Ecosystems, Resources, and Energy Flow:
Fig. 4.5: An
ecosystem
describes a
system of
living and
non-living
components.
A food chain
describes
energy flow
through an
ecosystem.
Three classes:
terrestrial,
saltwater, and
freshwater.

41. Fig 4.6: Systems that run on solar energy: basic life processes,
life-support processes, and life-threatening processes. Earth’s
atmosphere and surface reflect, scatter, and absorb 65 percent.
Insolation within Lower Atmosphere and Surface:

42. Global Distribution of Insolation:
Fig. 4.7: High latitudes receive low values; middle latitudes,
moderate values; and low latitudes, higher values. Note the
effect of cloud cover in the equatorial latitudes!

43. GLOBAL RADIATION BALANCE
________________________________________________________

44. Insolation and LatitudeInsolation and Latitude

45. Global Air Temp PatternsGlobal Air Temp Patterns

46. Global Distribution of Precipitation:
Fig. 4.8: Mean annual precipitation. Note general patterns!

47. Most abundant elements within the biosphere:
Table 4.1: On page 58.

48. Biogeochemical Cycle: Carbon Cycle:
Fig. 4.9: Excess CO2 is absorbed by plants, ocean, and lithosphere.

49. Biogeochemical Cycle: The Oxygen Cycle:
Fig. 4.10: The atmosphere is comprised of about 21 percent O2.

50. Biogeochemical Cycle: The Nitrogen Cycle:
Fig. 4.11: The atmosphere is comprised of about 78 percent N2.

51. Biogeochemical Cycle: The Phosphorous Cycle:

52. Cause-and-Effect Relationships: Biosphere: