Global Cycles: the flow of NRG and elements.

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Global Cycles the flow of NRG and elements.

• With stops at climate change
• The greenhouse effect
• C sequestration
• Ra
• And Global Biomes

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Biological Limits
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NRG cycling
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The Sun, our star, is the source of all NRG for
life on earth
X-ray image from Dec. 2002
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The Carbon Cycle
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NRG Atmosphere Balance
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The greenhouse effect
NASA CERES image shows the energy being lost from
the Earth and the atmosphere by thermal emission.
http//visibleearth.nasa.gov/view_rec.php?id45
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Is there ever any potential problem with linear
extrapolation?
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Oxygen
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Nitrogen Cycle
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NRG Cycle (food chain)
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InterdigitationThe Ecotone, a fuzzy boundary
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Global Biomes

• a large, recognizable assemblage of plant and
  animals in functional interaction with its
  environment strongly related to climate
• Tropical rainforest
• Tropical deciduous forest
• Tropical Scrub
• Tropical Savanna
• Desert

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Tropical Rainforest
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Tropical Scrub
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Desert
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Mid and High Latitude Biomes

• Mediterranean woodland
• Steppe
• mid-latitude grassland
• Savannah
• Deciduous forest
• Boreal Forest
• Tundra
• Mountain and Polar regions

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The Earth in Space
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What significance do the tropics of Cancer and
Capricorn have?
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Latitudinal Heat Balance
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Mediterranean woodland
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Steppe regions are transitional between desert
and grassland/forest biomes
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Savannah another transitional biome, between
forest and grassland
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Grasslands some of the most fertile soils on the
planet.
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Mid-Latitude Forests
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Boreal Forests
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Arctic Tundra
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Alpine tundra
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Altitude Compensates for Latitude
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Mt .Kilamanjaro, 200 miles S. of the equator
displays the full range of climatic conditions
from equatorial steppe and forests to tundra and
permanent ice fields
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Climbing Mt. Kilmanjaro
Photos courtesy of Will Spivey
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Adaptation and Succession

• A vast array of mechanisms have been developed to
  spread organisms to appropriate habitats.
• Organisms will take advantage of very small
  differences (micro-climates)
• Nothing is stationary, everything changes and
  organisms must adapt and shift with the changing
  conditions.

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The Limiting Factor

• Organisms spread to the outer limits of their
  biological range
• Usually a single factor prevents the further
  spread (or continued growth) of an organism.
• Nutrients (nitrogen, calcium etc.),
• water (not enough too much), temperature
  (extremes of heat and cold).

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Vegetative Succession

• Plant communities change on the landscape through
  time.
• After a disturbance (fire, a pond silting in, a
  landslide, an agricultural field) the first plant
  community to colonize the site is the pioneer
  plant community
• Following the first are a variable number of
  different communities these communities are
  called Seral stages
• Finally, barring additional disturbance the
  vegetative community that can best utilize the
  site becomes established the Climax stage.

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Succession in a pond. All lakes are very short
lived structures.
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Vegetative Succession

• A theory that holds under a given set of
  climatic/edaphic conditions vegetation will
  follow a path of vegetative succession from
• Colonizers to the climax vegetation
• that vegetation community best adapted to the
  conditions.

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An example for a hardwood forest biome
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Fire Ecology

• Smokey Bear was not fully correct.
• Many ecosystems depend on regular fire to create
  a unique ecosystem.
• The vegetation community can be called a fire
  climax

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Fire is a natural part of the ecosystem

• ground fires tend to burn through the low
  growing brush and small trees
• These flashy hot fires scorch the larger
  vegetation, but leave it largely intact.
• In some environments, natural fires are
  supplemented by controlled burns

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However,

• When natural fires have been suppressed, the fuel
  load can build much higher than would occur under
  a more frequent (natural?) fire regime.
• The resulting fires destroy virtually all
  vegetation, resulting not in a fire climax
  community, but bare soil suitable for a pioneer
  community. e.g. Yellowstone

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Sidebar Vegetative dispersal
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What is Natural?

• Is a beaver dam natural?

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• Is Wilson Dam Natural?