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187 Cards in this Set

  • Front
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soil water storage
-important bc plants haven't developed h2o storing ability

-stores h2o in times when precipitation isn't available to plants
---systems can still have high productivity & buffer climate in dry periods
humid regions in relation to energy & water
available to plants
rainfall exceeds the amt that can be evaporated

-energy limited (not h2o limited)
arid regions in relation to energy & water
available to plants
have more energy than water

-water limited in terms of production
Actual Evapotranspiration

-actual amt of water evaporated at a site

-measurement of ENERGY & WATER availability

-**most important predictor of patterns of
Terrestrial Productivity
Potential Evaporation

highest in semitropical cloudless areas
(areas limited by h2o availability)
= index of aridity

deserts = low
humid = value approaches 1

[reversed eq: PET/rainfall
dry = high values
wet = values lower than one]

*raising PET shows that we're warming the planet
matric potential
ability of water to adhere to a surface

1)physical comp of soil
3 classifications of soil water
1) superfluous water

2)available water

3)unavailable water
"superfluous water"
water in excess of field capacity

(susceptable to gravity)
available water
amt of water found between field capacity & wilting pt

(soil characteristic)
"unavailable water"
water held in soil below wilting point

1)inner capilary water
2)hygroscopic (basically nonliquid) water
soil textures in relation to plant available water
loam > clay >> sand
rules for soil / soil water
-only water in excess of field capacity can be removed by gravity

-until the top layer of soil reaches field capacity there's no movement of water

-arid soils are dried to permanent wilting pt on annual basis

--humid zone soils recharge to field capacity each year
depth of soil wetting equation
depth of wetting =
rain /
(field capacity - current h2o content of soil)
wetting patterns
soils with high field capacities retain more h2o / unit of soil

-soils w/ high field capacities wont be wetted as deeply as soils w/ low field capacities

-only soil water held @ surface vulnerable to evaporation (few cm @most)

-in arid zones clay soils more droughty than sand soil
(opp in humid)
soils comp of solids v pore space
50 % solids

(rest is gas & h2o)
formula for how much water is available to plants
field capacity - wilting pt
= h2o available to plants
textures in relation to plant available water held
loam > clay > sand
after water's filled to field capacity
extra water drains to deeper horizons

(how the soils recharge during dry seasons)

*top soil can be at field capacity while lower soils are at perm. wilting pt*
plant survival in arid ecosystems
plants attempt to use h2o as soon as its delivered

-when dry down proceeds plants can go dormant
plants compete for soil available water w/ surface evaporation
but depth evaporation can take water from is limited

-deeper water is only available to plants (roots)
importance of sand in arid areas
soil best for holding water for plants holds only 75% of water in sand ("droughty soil")

-how much water soil can hold/unit not important to plants -- its how much water can be provided

-sandy soils are better in arid areas

-sand soils grow more plants when rainfall < 37 cm

{clays & loams grow more plants when rainfall > 37 cm}
"weather" is generated by
latent heat & sensible heat

1)"ground heat flux" huge in deep lakes / oceans

2)smaller on land

3)storage (photosynthesis) trivial but veg effects huge bc
-effect on albedo
-effect on partitioning of heat (sensible & latent) due to evapotranspiration
regional/local controls
on water & energy cycles
fate of water
Function Of:
-available energy
-vegetation type
-soil texture

[fate of water:::
-ecosystem water budget
abreviations / terms

-Rn = net radiation balance (increase/decrease in energy content)

-S = solar radiation

-a = albedo

-L = net longwave rad

-LE = latent heat (used to evaporate water)

-H = sensible heat (pumped into kinetic energy of atoms to change state)

-G = energy transferred to & from ground

-S = storage = vPs = energy into plant chemical energy
vegetation's effects on outputs
albedo -- decreases

sensible heat -- decreases

latent heat -- increases

longwave rad -- decreases (bc of latent heat)
Potential Evapotranspiration

the mm's of h2o that can be evaporated if water isn't limiting
Actual Evapotranspiration

actual amt of water evaporated at a site

-how much solar energy present
-if water is available to evaporate

[deserts = lots of solar rad but no water = NO AET
arctic = lots of water but little solar rad = little AET]

**estimate of both water and energy**
AET in limited water areas
annual AET = mm of rainfall

*but when h2o is more abundant than energy (humid areas) AET will be LESS than rainfall value*
Soil Profile

(listed horizons)




O horizon
litter / soil organic matter (SOM)

A horizon
rooting zone

minerals & partially processed SOM
E horizon
weathering / leaching zone

mostly mineral
decomp of clays and minerals

predominantly minerals
C horizon
parent material (unweathered)
what makes nutrients available in the soil?

-provide mechanism to knock nutrients off exchange sites so they're in soil solution
weathering of parent material provides

-secondary minerals
(function as ion exchange sites)
Acids Provide

(carbonic acids, nitrate..)
NECESSARY to drive weathering


Get ions off humus & ion exchange sites!!!!!
what do "new nutrients" to the system do?
-come from either decaying plant material
-or weathering

--H+ exchanged for nutrients
----so sites continually replenished & not lost to leaching &such
"wilting point"
water soil can hold against root uptake

-depends on soil texture AND plant adaptations
"field capacity"
moisture content not susceptible to gravity
--held by soil
all pore spaces full

"plant available water"?
(Field Capacity) - (Wilting Point)
-Field Capacity
-Wilting Point
-Plant Available Water

-clay = .54 g/cm^3 (holds most water)
-loam = .38 g/cm^3
-sand = .17 g/cm^3

-clay = .36
-loam = .16
-sand = .08 (still plant available water til .08)

-loam = .22
-clay = .18
-sand = .09
residence time of soil component

calculated as
residence time = 1 / (decay rate)

(decay rate = inputs/amt of storage)
"Net Ecosystem Production"

-live biomass

-dead material
plant ecology

-concept of community as a superorganism
didn't like the way clements only focused on biota

-suggested that integration of biotic and abiotic can form ONE PHYSICAL SYSTEM


-advocate of hierarchy theory
Lindeman '40s
trophic dynamic concept

patterns of energy flow
leopold '49
sand county almanac

some nutrient cycling
Odum '53

-a lot based on lindeman's energy flow work

-only book til ~20 yrs later

-ignored evolutionary ecology
first terrestrial ecosystem studies on nutrients conducted

-silent spring

-first real wave of enviromentalism

-"international biosphere program" -(funding)
LTER network

long-term ecological research

the ecosystem approach

(of systems)

based on
hierarchy theory
hierarchy theory
-OBJECT (ecosystem / organism)
-has an ENVIRONMENT which constrains the object via energy & material
---provides the CONTEXT for which object is explained

-how the object FUNCTIONS w/i the enviro is explained by looking at its PARTS
-the parts are a system that gives the object its behavior & characteristics
level above the object?

(hierarchy theory)
the context - the enviro

level below / within the object

(hierarchy theory)

-explain HOw the object works
"units" of ecosystem ecology?

-mass recycling....
an ecosystem studied for enviro change issues

must be looked at
@level above
-showing consequences of change (the changing enviro of an organism)

@level below / within::
-as a mechanism for change (ie part of a higher unit)
1st law of thermodynamics
energy cannot be created or destroyed

-but may be converted from one form to another
2nd law of thermodynamics
-all energy transfers result in some lost / unusable energy
(waste heat)

-no energy conversion is 100% effective
energy needed to raise 1 cm^3
of H2o 1*C @ 15*C
solar constant?
2 calories / cm^2 / min

biosphere bathed in solar radiation at this rate

-the amount of radiation received at surface perpendicular to sun @ outer space boundary
what form is solar radiation in?
electromagnetic radiation
max energy received @ outerspace boundary?
2 cal / cm^2 / min
(the solar constant)
-@ perpendicular surface

-surfaces moving from 0 to 90* = amt of energy drops to 0
departing energy = entering energy

on avg
@ outerspace boundary
solar rad in = albedo + longwave out
vegetation albedo
15 - 20 %

snow ~ 95%
albedo of clear water
very low when perpendicular to light source

-unit of ocean absorbs more light than unit of land
energy exchange at outerspace boundary?
all electromagnetic radiation

-open system w regard to energy
--closed to matter
----energy needing matter as carriers can't pass
latent heat
energy needed to change state of water

from frozen to liquid and liquid to water vapor
sensible heat
associated w the heating of materials
@ earth's surface

energy can....
-latent heat

-sensible heat

-go into momentum (physical transport of mass)

-chemical energy (photosynthesis)

-transported into ground (sensible)
photosynthesis energy returned by respiration

energy transported into ground re-released into atmosphere

annual average = 0

(numbers can be ignored)
avg surface at best will receive how much solar rad
HALF the solar constant

only 44% of that half is visible light
& can be used by photosynthesis

2 reasons energy varies over globe?
1) latitudinal patterns

2)land v water patterns
net radiation input

land v water
net radiation input
lower over land

higher over water

-Lower Surface temp of water allows more solar energy to be stored (as sensible & latent heat)
--than is lost by Longwave rad (function of temp of obj)
subsidy of energy from tropics to poles
energy captured in tropics transfered to poles
---(eventually lost at poles as longwave rad)

-poles would be MUCH colder w/o this energy transfer
linkage of energy & hydrologic cycles
evaporation from land / ocean removes energy from surface
-transfers to atmosphere
-rereleased in cloud formation

(solar powered global water cycle)
hydrologic cycle
-sizes / rates of components vary significantly

(residence time for h2o in atmosphere = 11 days
residence time in ocean = 3500 yrs)
global Precipitation patters
-declines from tropics to poles
--but peaks at 40* N & 40*S

----the peak in N hemisphere is less extreme

-land masses change precip patterns
el nino / southern oscillation

repeatable pattern

but largely unpredictable
rainfall & temp predict what type of ecosystem SHOULD be there..
but varies greatly with overlab
water's albedo
100% for very low angles

-after sun 25% above horizon
---albedo's less than 10%

state factors
soils are a function of

-climate (cl)

-organisms (o)

-topography (r)

-parent material (p)

-time (t)

weathering definition

rocks + acid = secondary minerals + nutrients
causes of weathering



essential plant elements

(must have for survival)
C, H, O, P, K, N, S, Ca, Fe, Mg, Mn, B, Cl, Cu, Zn, Mo

chopkins cafe mightygood mighty night but for clara and cousin moe.
limiting nutrients

(not an abs quantity needed)
(similar to stress)
(can be limiting bc everything else isn't)


--potassium (agroecosystems)
--iron (polar oceans)
nitrogen limiting in ::
-temperate terrestrial
phosphorous limiting in ::
-temperate aquatic

limiting reasources can be...
-single resouce

-multiple limitation

---ecological succession
----geologic time
---growing season
source of soil fertility
weathering of parent material
2 factors important for weathering & creating soil

oldest soils?
in tropics
weathering of igneous & metamorphic rocks

1)in cold temperate

2)in tropical
1) cold temperate::
silica sand

2) tropical
iron & aluminum oxides
parent material produces

2)substrates (clays)
--short term storage
--w/o this storage there would be too much leaching
open ocean low in productivity
bc no soil

-no site to store nutrients
"soil fertility"
ability to provide plants with essential nutrients

fertile soils have:
-large stores of nutrients
-adequate water for delivery of nutrients
soil succession

parent material + acids = nutrients + secondary minerals (2:1 clays)

2:1 clays + acids = nutrients + 1:1 clays

1:1 clays + acids = iron / aluminum oxides + nutrients

iron / aluminum oxides + acids = dissolved iron / aluminum
2:1 clays =
secondary minerals
soil succession is....
the decay of soil

(to dissolved iron / aluminum)

-soils reappear 10 mill yrs later as new parent material
(Cyclic by geologic time)
most important factors for soil @ GLOBAL scale??

time the process has had to occur
weathering of parent materials most extensive...
in the tropics
tropics soils can still be fertile due to

volcanos earthquakes landslides
soil horizons result from
interaction of

Cl, O, R, P, T
horizons in old tropic soils
only E (leached) zones
Arctic soils
raw organic matter
over frozen mineral soil


O layer only
boreal / coniferous forests
dissolve everything but silica

(white layer in soil)
most fertile soil?

-sufficient rainfall & temp
== 2:1 clays
.. well mixed w/ humus

very young soils?

lack of water
= lack of acids
= lack of nutrients
Soil Fertility

-nutrients for plants come from soil solution
-nutrients in soil solution vulnerable to leaching & grabbed by plants / microbes
-nutrients in clay / humus available & not vulnerable to leaching
-nutrients locked in organic matter not available


Controllers of CLay & Humus?
-------(parent material + acids = clay + nutrients)
-humus made during decomposition

nutrient storage sites have the ability to hold on to cations (& anions)
NET radiation balance
(+/- in energy content)
Solar Radiation
net longwave radiation
Latent Heat

(used for evaporation of water)
Sensible Heat

(kinetic energy of atoms... used to heat things)
energy transfer in / out of ground
"vPs" (S?)

energy going into plant's chemical energy
factor determining plant available soil moisture?
"matric potential"
attraction between H2o & surfaces
amount of water soil can hold
1) total surface area (amt of clay & humus)


[surface area : volume
clay > silt > sand]
texture w highest nutrient & h2o holding capacity
highest h2o infiltration rate
texture w highest permanent wilting point
depth of moisture

depth of moisture = ppt / (field capacity - current)
coarse soils
fine soils
-low field capacity
--h2o goes deeper into soil

-high field capacity
--h2o hung up in top layers
(carbonate accumulate - then blocks h2o)
"capillary action"
brings salt to surface
why can sand sometimes provide more water?
because water goes deeper (isn't hung up in top layers)
-not susceptible to evaporation
best soil

when h2o isn't limited

-have the CEC
--hold the nutrients
short grass
tall grass
short grass = high clay content

tall grass = coarse soil
2 factors explaining
1) texture

2) precipitation
plants in sand

(below ground v above ground)
ground = 2/3

air = 1/3
wilting point controlled by

-the amt of h2o they can pull off

(doesn't vary too much tho between plant species)
area around root that they're able to gain h2o from
plants get help gaining h2o from
mycorrhizae fungii

-plants give them C, H, O (organic stuff)
-they give H2o in return

-plants control if relationship happens

-used by both fibrous & tap roots
Tap Roots
better at getting deep soil water
fibrous roots
better at getting shallow soil water

effect on h2o
preven h2o from going deep
tropical shrublands

Boreal / Deserts / Coniferous / Deciduous / Grassland


---- no need for deep roots
Hydraulic Lift
-take h2o out of deep soil
-dumps it into shallow soil @ night
-grabs same h2o in day
(gets more nutrients -- bc in shallow soil)

-susceptible to competitors
surface turbulance increases...
the transfer of sensible & latent heat to the atmosphere

[caused by winds blowing across rough surface.. .transports warm moist air away & brings cool dry air back]
how does LE (latent heat) effect H (sensible heat)
latent heat = evaporation of water
--->cools the surface
-reduces the difference in temp between surface and air
--therefore REDUCING sensible heat
(the temp difference between surface and air is what drives sensible heat)
how does H (sensible heat) effect LE (latent heat)
sensible heat warms the surface air
-which increases the amt of water vapor the air can hold
--causes the movement of moist air away from surfaces
moist ecosystems

w regard to latent & sensible heat
high moisture = higher rates of evapotranspiration (lower bowen ratios)
turbulent winds

effect of latent & sensible heat
turbulent winds prevent temperature buildup at surface... reducing sensible heat flux (lowering bowen ratio)
a tight linkage between the energy budget & hydrologic cycle
a low bowen ratio

(low sensible heat, high latent heat)
"ecosystem processes"
transfers of energy and materials from one pool to another

-energy enters w light
-lost when organic matter goes back to co2

movement of materials:

biotic components
-absorbtion of minerals by plants
-decomp of dead matter
ecosystems range in size:::
from rock ecosystem

to forest

to global ecosystem
ecosystems at "steady state" if
balance between inputs and outputs to the system show no trend w time

(accept temporal and spatial variation == no ecosystem is in true equilibrium)

-even at steady state - plant growth varies w the seasons

systems approach to studying ecosystems

(systems approach = patterns of energy and such)
what enviro questions can be addressed by ecosystem ecology
that can't be addressed by
population or community ecology
-conserving biodiversity approach
(not just species approach)

-how we're affecting global budgets of materials / energy

-global patterns of co2 & pollutants in the atmospheregive evidence of major locations / causes of global problems
ecosystem analysis tries to understand factors that regulate


state factors control on processes

-strengths & weaknesses
-considered the controls over processes (not just patterns)

-ecosystem processes both control & are controlled by factors

-"interactive controls"
differences between state factors & interactive controls
state factors aren't controlled by the ecosystem

interactive controls both control the ecosystem and are controlled by the ecosystem
(light, temp, moisture)
human activities affecting interactive controls
-water availability (we use ~ 1/2 world's runoff)
-disturbance regime
-biotic diversity
-transformation of land
-gasses (cfc's---ozone destruction)
-chemicals (ddt)
of the 100% shortwave that comes to outer space boundary...

-31% albedo (shortwave reflected from clouds)

-20% absorbed by atmosphere

-49% reaches earth's surgace

69% emitted as longwave (due to low surface temp)

-the remaining is transferred from earth's surface to the atmosphere via latent or sensible heat
atmosphere absorbs how much long wave? (%)
atmosphere absorbs 90% of the longwave emitted by the surface

-its then reradiated in all directions as longwave (greenhouse effect!)
greenhouse gases?
-water vapor

-carbon dioxide


-nitrous oxide


(="radiatively active gasses")
without the greenhouse effect earth would be?
33*C cooler

-probably not support life
climate variability due to
-greater heating at equator than poles

-continents spread unevenly
clouds effects on radiation
-high albedo
--reflect more incoming shortwave than earth's surface
(high clouds)

-composed of water vapor
--absorb a lot of longwave
(low clouds)
unequal heating of earth's surface
-equator receives more incoming solar radiation
---rays perpendicular @noon
---high lat = rays spread out (less rad / unit ground area)

-@ higher lat rays have longer path thru atmosphere ... more rad absorbed, reflected, scattered before reaches surface

= higher temps in tropics
(drives atmospheric circulation)
the movement of air from surface up! (beginning of atmospheric circulation)
at equator the transfer of energy from surface to atmosphere = strong heating @ surface

-warming causes air to expand - less dense
--decrease in pressure w height = continued expansion
-->rising air cools

-cooler air has lower capacity for water vapor
--rains (releases latent heat)
--latent heat lowers the rate @ which air cools --- so can make air warmer... continue to rise
atmospheric circulation in full
-surface air rises most strongly @ equator
-expansion of equatorial air creates horizontal pressure gradiant
--causes the risen equatorial air to to flow toward the poles
-poleward moving air cools due to longwave emission to space
-gets smaller in volume bc earth's SA = smaller
--creates higher pressure
--air subsides
--pushes surface air back toward equator
hadley cell
driven by expansion & uplift of equatorial air

(0* - 30*)
Ferrel cell
driven indirectly by changing processes

(30* - 60*)
polar cell
driven by subsidence of cold converging air at poles

(60* - 90*)
coriolis force
arises bc earth is rotating

-deflected right in N hemisphere

-deflected left in S hemisphere

(reason for 3 cells, not 1)

-create jet streams & westerlies... ne trade winds
uneven distribution of land and oceans ....
creates uneven pattern of heating

-@ 30* N & S air descends stronger over cool oceans bc air is cooler and more dense over the ocean (S)

-creates high pressure zones & low pressure zones
(explains ferrel cells)
-low pressure centers rise to balance subsiding air in high pressure centers
ocean circulation's effects on climate
accounts for 40% of heat transfer from equator to poles
vegetations effect of climate
effects climate thru its effect on the surface's energy budget

-forests have lower albedo than grasslands

-energy absorbed by vegetation transferred to atmosphere by L, LE, & H

-forests = more precipitation
= lower temp
= more evapotranspiration
longwave radiation's dependence on surface temp
-surface temperature higher when lower albedo
-also higher temp when there's little water to evaporate
-also higher temp when surface is smooth (inefficient in transferring sensible & latent heat to atmosphere)

high pressure zones
-N & S poles
-30* N & S

-air descends, precipitation is low
high pressure zones
- 60* N & S

air rises, precipitation is high
soil properties result from a balance of
soil formation
soil loss
erosion rate
-influenced by topography
-depositional areas at bases of slopes (deep fine textured soils)
--higher rates of ecosystem properties
soil formation
depends on balance between
-soil development

-highly weathered landscapes = erosion renews soil fertility by exposing less weathered materials (new source of nutrients)
development of soil profiles
soils develop thru:::
-addition of materials
-transformation of these materials
-loss of materials
additions to soils

-organisms w/i ecosystem
soil transformations
(carbon dioxide and nutrients

(produces more stable forms)

"soil texture"

the proportions of soil particles of different sizes

clay < silt < sand

clay = largest propotion of secondary minerals
-largest SA:Volume ratio
--hold most h2o
an ecological system consisting of all the organisms and the abiotic enviro w which they interact in a given area
source of acid in chemical reactions
-most important
-co2 dissolves and reacts with water
-then ionizes to produce H+ ions