Brief review

1
Brief review
SA 4?r2 3 V 4/3?r3 r
r 2
r 4
So, SA/V is lower for bigger sphere
? P - ? Water potential turgor pressure -
osmotic pressure Water moves from higher
potential to lower potential Q if a fish has ?
of 0.2 MPa, and lake water has ? of 0.1 MPa,
will water diffuse into or out of the fish?
2
Nutrient cycles

• Carbon, nitrogen, phosphorous

3
Whats a nutrient? An element essential for an
organisms maintenance and growth that must be
obtained from the environment or by consumption
of other organisms
4
Liebigs Law of the Minimum

• Organismal growth will be limited by the
  necessary resource that is the least available
  (or the most difficult to obtain).
• E.g., for most desert plants, water is the
  limiting resource.

5
Carbon cycle active compartments 1.
Photosynthesisremoves C from atmosphere (
sink) 2. Respirationadds C to atmosphere (
source) Before industrialization, source
sink Note Respiration increases with rising
temperatures photosynthesis does not
6
Carbon balance in oceans
CaCO3 H2O CO2 Ca 2HCO3-
Insoluble form of carbon
Soluble form of carbon
Photosynthesis removes CO2, drives reaction to
the left calcium carbonate drops outs of
solution and carbon enters storage poolis taken
out of active carbon cycle
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Nitrogen cycle Source 78 of atmosphere
N2 N the limiting nutrient in terrestrial
ecosystems, oceans Primary input to
biosphere before industrialization N-fixation
by lightning, bacteria
8
Bush lupine N-fixing shrub native to northern CA
Now invasive in dune communities elsewhere in CA
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California lilac (Ceanothus spp.)

• Chaparral shrubs with N-fixing bacteria in
  association with their roots

10
White alder riparian trees

• Also with symbiotic N-fixing bacteria in roots

11
Effect of nitrogen fertilizer on
species diversity in a Minnesota grassland
Control plotno fertilizer
Plot with N-fertilization
12
Bird rockAgua Caliente, near Santa Barbara
Photo by Sue Beneck

• The white deposits? Guano, full of P