Biosphere and Climate

1
Biosphere and Climate

• Biology 150-009
• Ms. Chappell
• August 24, 2006

2
Earths Atmosphere

• Earths environment, a layer of gases surrounding
  the planet
• Does not equal space space means void

Image courtesy of csep10.phys.utk.edu/.../
earth/atmosphere.html
3
Atmosphere Near Earth

• Troposphere sea level to 12 km
• mixture of N2 (78) O2 (21) CO2, Ar, CH4,
  etc. (1) 100
• Transitional zone - 12 21 km above the earth
• Stratosphere 21 km to 48 km above the earth.
  
• Area of interest 20-35 km
• Why? Most important feature OZONE!

Fig. 32.17
4
Stratospheric Ozone

• Two-atom oxygen (O2) from life processes
  (photosynthesis of algae etc.) was and still is
  struck by high-energy sunlight and transformed
  into three-atom oxygen, or ozone (O3), in the
  stratosphere.
• Ozone buildup eventually filtered out 99 of
  the suns ultraviolet radiation (UV), allowing
  life to leave the oceans and begin forming on
  land 460 million years ago.

Image courtesy of www.solcomhouse.com/ ozone.htm
5
Preview of things to come

• Human effects on Earths atmosphere
• Stratospheric ozone thinning and holes
• Surface ozone production
• Global warming

6
Climate

• Climate average weather condition, including
  temperature, precipitation, and wind, in a
  particular region
• What causes different climates, the extremes of
  hot and cold dry and wet and everything in
  between?

7
Determining Factors of Climate

• Large-scale
• Tilt of the Earth
• Circulation of the atmosphere
• Smaller, or more local, scale
• Changes in altitude
• Movement across mountain ranges (rain
  shadow)

8
Tilt of the Earth

• Earth is at 23.5 tilt off its perpendicular axis
  with its orbital plane
• Location on Earth, in regard to tilt, determines
  amount and angle of suns energy received
• Impact to rate of photosynthesis, or ability to
  sustain different amounts of life

9
Circulation of the Atmosphere

• Tilt of Earth on its axis is reason behind
  circulation where more sunlight strikes (i.e.,
  direct sunlight vs. oblique light)
• air is warmer
• warm air rises
• warm air holds more moisture

Fig. 32.23
10
So what is the effect of all this air mass
circulation and rain on the Earth?

• Fig. 32.24

Fig. 32.24
11
So why do some latitudes have both wet, green
areas and deserts?

• Moving up a mountain is similar to moving away
  from the equator (air temperature decreases).
• Moving across mountain ranges is similar to
  rising and descending cells of large air masses
  with their moisture releases and uptakes.

Fig. 32.25
12
Climate Vegetation?

• Dominant vegetation (e.g., grasses, coniferous
  forests, etc.) differs between climate regions.
• When large areas of land with dominant vegetation
  types are viewed as large-scale ecosystems, refer
  to them as biomes each type comes complete with
  its own dominant vegetation, animals, climate,
  nutrient cycling patterns, and problems.
• Next class, biomes! Remember your journal entry
  for the week!