Make a graph of plant production energy capturedyear into usable

1
Make a graph of plant production (energy
captured/year into usable biomass) Whats on
your x axis???
2
Wednesday, Feb 4 Essay due this Friday First
Hour Exam next Monday, Feb. 9th
3
Water inputs to ecosystems

• Precipitation
• THE major water input to ecosystems
• Groundwater (in some ecosystems)
• Fog deposition (in some ecosystems)

Redeposition of snow in the alpine/subalpine!
4

• Getting water
• into system

text
(note humid bias here.)
5
(text)
Ecosystems differ in canopy storage Depends
mainly on LAI Differs among species

(LAI leaf area index m2/m2 of foliage)
6
Table 1a. Annual mean atmospheric deposition,
throughfall, stemflow and net canopy exchange for
a Douglas fir site on the western slopes of the
Washington Cascades(). This site receives no
significant fog/cloud inputs.

Soils get 85 of precipitation
() Data adapted from Johnson and Lindberg,1992
7
Table 1b. Annual mean atmospheric deposition,
throughfall, stemflow and net canopy exchange for
a high elevation red fir site in the Great Smokey
Mountain National Park, North Carolina(). This
site experiences relatively high inputs of
anthropogenic pollutants and a large component of
fog/cloud inputs.


Soil gets 106 of precip!
8
Table 1.c Tallgrass Prairie in Kansas ____________
____________________ Precipitation
91.2 cm Throughfall annually burned 68.4
cm (76) unburned 52.8 cm
(58) __________________________________
9
In moist ecosystems, Precipitation directly
regulates streamflow
Yeah, more water than energy to evaporate it
10

• Storing and
• returning the
• water

(note humid bias here.)
11
Basic principle of water balance in ecosystems

• Soil is like a bucket
• Inputs
• Mainly precipitation
• Outputs
• Evaporation
• Transpiration
• Drainage

(this word model converts to box and arrow
model)
Surface, groundwater
12
Simple box and arrow model
storage
Virtually all variables (storage and fluxes under
biotic controls!!!
13
Potential evapotranspiration (PET) is the amount
of water that could be evaporated and transpired
if there was sufficient water available (evapora
tion under unlimited water Process is energy
limited) In cold environments PET is low due to
low energy Soone can think of PET as the water
equivalent of solar radiation (high at tropics,
low at poles)
14

Actual evapotranspiration (AET) is the quantity
of water that is actually removed from a surface
due to the processes of evaporation and
transpiration. (a concurrent measurement of
both water AND energy availability) Why do
ecologists get really excited over AET?
15
Evapotranspiration is the best predictor of
plant productivity at a global scale! If you
only can measure one variable. measure this
one!
16
In humid environments, by definition, water is
rarely limited and therefore AET will approach
PET In humid tropics, expect high AET and PET In
semitropical deserts, low AET and very high
PET In semihumid to semiarid environments,
plant-soil interactions can strongly influence
AET
17
AET/PET as ecosystem characteristic
18
Soil water storage provides a mechanism to
maximize AET (and therefore all the ecological
services associated with AET such as a)
keeping the surface from heating b) providing
the conduit for nutrient acquisition c)
allowing for CO2 uptake.
19
Simple box and arrow model
storage
In arid zoneAET PPT (rainfall)and only part
of the storage space is used
20
Simple box and arrow model
storage
In humid zones, all flows possible.
21
Eastern Deciduous Forest A Humid Environment
Coweeta
22
Soil storage allows AET when PPT not available
23
What the plant roots see.(plains of Wyoming)
24
The tallgrass prairie
semi humid
Not quite enough water to make it Through the
summer!
25
The Jornada desert
Under high energy, low PPT, AET PPT
(monthly rainfall)
26
Streamflow is the leftovers after soil storage
and ET are met

• Over long term, runoff depends on ppt and ET

27
The energy and water cycles are
intertwined Soils and plants allow for more
evapotranspiration, More latent heat Therefore
less sensible heat
28
Iowa a summer wet system
Salt Lake City a winter wet system