EESA01 Lecture4 - 2011-compressed

EESA01 Lecture4 - 2011-compressed - EESA01
Lecture
4


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Unformatted text preview: EESA01
Lecture
4
 Finish
Global
Biogeochemical
Cycles
 Then:
Global
Energy
Balance
and
 Global
Water
Cycle
 Lecture
4
–
Energy
and
Water
 1
 GPP
vs.
NPP
 •  Gross
Primary
 ProducFvity
(GPP)
is
the
 total
uptake
of
energy
 into
a
system
(i.e.,
all
the
 energy
fixed
by
a
plant
 as
glucose).

 •  NPP
is
the
rate
at
which
 plants
use
that
energy
to
 gain
dry
mass.

Some
of
 GPP
is
used
to
make
 mass;
some
is
respired.
 Lecture
4
–
Earth
Systems
 2
 NPP
vs.
NEP
 •  POSITIVE
net
primary
producFvity:

 •  hVp://www.youtube.com/watch?v=OHw68EI8Dz8&feature=relmfu
 •  DecomposiFon/heterotrophic
respiraFon:

 •  hVp://www.youtube.com/watch?v=JKXf6VBDDQg&feature=relmfu
 •  NEP
=
NPP
–
Ecosystem
RespiraFon
 •  Ecosystem
respiraFon
includes
both
the
 respiraFon
of
carbon
above
the
surface
and
 from
soil.
 Lecture
4
–
Earth
Systems
 3
 Measuring
ProducFvity
and
 RespiraFon
 







ProducFvity
 
 





 Lecture
4
–
Earth
Systems
 
 
 
 
 









RespiraFon
 


(note
that
it’s
dark)
 Photos from: http://soilweb.landfood.ubc.ca/ 4
 Factors
AffecFng
NEP:

 1.
Nutrients
 •  •  Nutrients
(especially
macronutrients
like
nitrogen
and
 phosphorus)
can
be
limi.ng
factors
for
producFvity.
 Nitrogen
usually
limi.ng
factor
in
marine
systems,
 usually
phosphorus
in
freshwater
systems.

 Lecture
4
–
Earth
Systems
 5
 Factors
AffecFng
NEP:

 2.
Oxygen
 Aerobic respiration: C6 H12O6 + 6O2 → 6CO2 + 6 H 2O Energy Produced = 2872 kJ per mol glucose Examples of anaerobic respiration: − € € 2.5C6 H12O6 + 12 NO3 → 6 N 2 + 15CO2 + 12OH − + 9 H 2 0 Energy Produced = 2715 kJ per mol glucose C6 H12O6 → 3CO2 + 3CH 4 Energy Produced = 210 kJ per mol glucose Lecture
4
–
Earth
Systems
 6
 Biogeochemical
Cycles
 •  Earth
is
a
“closed”
system.

Open
to
energy,
but
 maVer
“cycles”
(is
circulated)
within
it
over
and
 over
again
(some
VERY
minor
excepFons).
 •  MaVer
travels
through
the
many
spheres
of
 earth
conFnuously.

 •  From
a
biogeochemical
cycle
standpoint,
by
 maVer,
we
usually
are
referring
to
elements,
 such
as
C,
N,
P,
S,
and
Fe.
 Lecture
4
–
Earth
Systems
 7
 Biogeochemical
Cycles
 •  MaVer
circulates
between
pools
or
reservoirs.
 •  The
volume
of
material
moving
among
 reservoirs
per
unit
Fme
(a
rate)
is
called
a
flux.
 •  Fluxes
are
not
necessarily
stable
(e.g.,
we
have
 greatly
affected
the
flux
of
C
to
the
 atmosphere).
 •  Residence
3me
(TR):
average
amount
of
Fme
a
 molecule
or
atom
stays
in
a
pool.

 •  Sources
vs.
Sinks.
 •  Lots
of
feedbacks
in
biogeochemical
cycling.
 Lecture
4
–
Earth
Systems
 8
 Reservoirs,
Sinks,
Sources
 Lecture
4
–
Earth
Systems
 9
 Global
Carbon
Cycle
 Lecture
4
–
Earth
Systems
 10
 Importance
of
Nitrogen
 •  •  •  •  •  78%
of
atmosphere
 6th
most
abundant
element
on
earth
 Key
ingredient
in
proteins
and
DNA
 EssenFal
nutrient
for
plant
growth
 Actually
a
relaFvely
inert
element
and
is
quite
 scarce
in
lithosphere,
hydrosphere,
and
 biosphere.

 Lecture
4
–
Earth
Systems
 11
 Key
Processes
in
the
N
Cycle
 •  Nitrogen
Fixa3on:
combinaFon
of
nitrogen
gas
 (N2)
with
hydrogen
to
form
ammonia
(NH3)
and
 subsequently,
the
biologically
available
and
 soluble
ammonium
ion
(NH4+).

 –  Two
driving
processes:
lightning
and
nitrogen‐fixing
 bacteria.
 •  Nitrifica3on:
Conversion
of
NH4+
to
NO2‐
and
 then
NO3‐
by
specialized
bacteria.

Plants
take
 up
NO3‐.
 •  Denitrifica3on:
Conversion
of
NO3‐
back
to
N2
 gas
by
specialized
bacterial
communiFes.
 Lecture
4
–
Earth
Systems
 12
 Global
Nitrogen
Cycle
 Lecture
4
–
Earth
Systems
 13
 Human
AlteraFon
of
N
Cycle
 •  •  •  •  •  •  Doubling
of
nitrogen
fixaFon.

Due
to
Haber‐Bosch
 process
and
increased
producFon
of
legumes
 (soybeans).
 Increased
atmospheric
N2O
(greenhouse
gas)
and
other
 NOx
(produce
smog).

Due
to
fossil
fuel
burning
and
 animal
waste
decomposiFon.
 DepleFon
of
micronutrients
(Ca,
K)
from
soils
(N
 ferFlizers
make
them
more
mobile
and
they
flush
out).

 Acid
rain.
 EutrophicaFon

devastaFng
to
fisheries
(especially
 coastal
marine
fisheries).
 Increase
plant
growth
and
carbon
storage.
 Lecture
4
–
Earth
Systems
 14
 EutrophicaFon
 •  The
process
of
nutrient
over‐enrichment,
 blooms
of
algae,
increased
producFon
of
 organic
maVer,
and
ecosystem
degradaFon
 Lecture
4
–
Earth
Systems
 15
 Gulf
of
Mexico
“Dead
Zone”
 This makes this guy SAD! Lecture
4
–
Earth
Systems
 16
 Global
Phosphorus
Cycle
 Lecture
4
–
Earth
Systems
 17
 Importance
of
Phosphorus
 •  Key
component
of
cell
membranes,
DNA,
and
 ATP
(energy).

 •  Oten
limiFng
nutrient
for
autotroph
growth.
 •  Biogeochemical
cycle
is
largely
restricted
to
 lithosphere
and
hydrosphere
(NOT
 atmosphere).


 •  Cycle
is
largely
driven
by:
 –  –  –  –  solubilizaFon
 precipitaFon
 assimilaFon
 decomposiFon
 Lecture
4
–
Earth
Systems
 18
 Human
AlteraFon
of
the
P
Cycle
 •  Mining
of
phosphorus‐bearing
rocks
for
ferFlizer
 producFon.

 •  Wastewater/sewage
discharge.

 •  EutrophicaFon
via
over‐ferFlizaFon
(mainly
 freshwater).
 •  Use
of
phosphate
detergents.

 Lecture
4
–
Earth
Systems
 19
 Global
Mercury
(Hg)
Cycle
 Lecture
4
–
Earth
Systems
 20
 Global
Energy
Balance
and
 Global
Water
Cycle
 Lecture
4
–
Energy
and
Water
 21
 Basics
of
Energy
and
Climate
 •  A
warm
substance
is
warm
because
it
holds
more
 energy
than
a
cold
substance.
 •  If
a
warm
substance
becomes
cooler,
it
is
because
 energy
is
leaving
the
substance.
 •  In
a
steady‐state
Earth,
incoming
energy
will
equal
 outgoing
energy
over
a
year.
 •  If
this
is
not
true,
the
Earth
will
either
warm
up
or
 cool
down.
 •  Earth’s
climate
is
all
about
energy
fluxes
and
the
 balance
between
outgoing
and
incoming
energy.
 •  Energy
cannot
be
created
or
destroyed,
just
 transferred.
 Lecture
4
–
Energy
and
Water
 22
 Earth
is
“Open”
to
Energy
 •  InsolaFon
is
energy
received
from
the
Sun
 (INcoming
SOLar
radiATION).

 •  InsolaFon
is
“shortwave”
radiaFon.

 •  Shortwave
radiaFon
inputs
include:
 –  Ultraviolet
light
(UV)
 –  Visible
light
 –  Near‐infrared
wavelengths
 •  InsolaFon
drives
most
processes
on
Earth.
 •  InsolaFon
and
Earth’s
Flt
and
rotaFon
produce
the
 daily,
seasonal,
and
annual
paVerns
of
day
length
 and
climate.
 Lecture
4
–
Energy
and
Water
 23
 Seasons
 Lecture
4
–
Energy
and
Water
 Figure 13.5 24
 ElectromagneFc
RadiaFon
 Wavelength:
ElectromagneFc
radiaFon
 travels
in
“waves”;
the
distance
between
 wave
peaks
is
wavelength.

 Lecture
4
–
Energy
and
Water
 25
 Why
is
InsolaFon
Shortwave
 RadiaFon?
 Wien’s
Displacement
Law:
wavelength
at
 which
maximum
energy
radiaFon
occurs
is
 inversely
related
to
surface
temperature.
 λmax 2897 = T λmax = maximum radiation wavelength (in µm) T = temperature of surface in degrees K. Lecture
4
–
Energy
and
Water
 26
 ElectromagneFc
Spectrum
 λmax of Sun (6000 K); of Earth (290 K)? (absolute zero = 0 K; 0 °C = 273.15 K) Lecture
4
–
Energy
and
Water
 27
 Energy
Flux
 •  The
rate
(amount
per
Fme)
of
energy
 (Joules)
received
at
a
surface
is
called
Power
 (J
s‐1).

This
is
a
WaV
(W).
 •  Power
per
surface
area
is
an
Energy
Flux
 and
is
measured
in
W
m‐2.

 •  The
rate
of
energy
emiVed
by
a
substance
is
 governed
by
the
Stefan‐Boltzmann
Law.

 QR = εσT 4 σ = 5.67 x 10-8 W m-2 K-4 Lecture
4
–
Energy
and
Water
 28
 Solar
Constant
 •  DefiniFon:
the
rate
at
which
insolaFon
is
received
 at
the
outer
atmosphere
of
Earth.
 •  Solar
constant
=
1367
W
m‐2
 •  Energy
hiwng
Earth
averages
342
W
m‐2.
Why?
 Lecture
4
–
Energy
and
Water
 29
 LaFtude
Controls
 Lecture
4
–
Energy
and
Water
 Figure 13.4 30
 Earth’s
Energy
Balance
 •  The
Sun
emits
shortwave
radiaFon
(K),
 whereas
the
Earth
emits
longwave
radiaFon
 (L).
 Lecture
4
–
Energy
and
Water
 31
 Albedo
and
Available
Energy
 •  Earth
reflects
about
30%
of
the
insolaFon
it
 receives
and
another
20%
or
so
is
absorbed
in
the
 atmosphere.

 •  This
reflecFvity
is
termed
albedo.

 •  0
≤
α
≤
1
 •  Albedo
is
related
to
a
substance’s
properFes
:
 snow
has
high
albedo
(0.8‐0.95)
whereas
asphalt
 has
low
albedo
(0.05‐0.1).
 •  The
50%
of
available
energy
that
Earth
absorbs
 goes
toward
important
processes
like
 photosynthesis
and
driving
our
climate
(i.e.,
 through
evaporaFon,
winds).

 Lecture
4
–
Energy
and
Water
 32
 What
Takes
More
Energy?
 1.  Raising
the
temperature
of
a
glass
of
 water
by
1°C.

 2.  Raising
the
temperature
of
a
glass
of
 water
by
50°C.

 3.  Changing
ice
at
0°C
into
water
at
0°C.

 4.  Changing
water
at
100°C
into
water
 vapour
at
100°C.
 Lecture
4
–
Energy
and
Water
 33
 What
Happens
to
the
Energy
 •  3
main
uses
of
the
70%
of
insolaFon
that
 is
absorbed
by
Earth:

 1.  HeaFng
the
ground
(ground
heat
flux)
 2.  Providing
warmth
(sensible
heat
flux)
 3.  Changing
phases
of
water
(latent
heat
flux)
 •  Sensible
and
ground
heat
can
be
 measured
by
a
thermometer
whereas
 latent
heat
cannot;
it
is
“hidden”
energy.
 Lecture
4
–
Energy
and
Water
 34
 Desert/Oasis
Example
of
Energy
 ParFFoning
 Oasis Desert Lecture
4
–
Energy
and
Water
 35
 The
parFFoning
of
energy,
 especially
toward
latent
energy,
 is
fundamental
to
global
 HYDROLOGY
 Lecture
4
–
Energy
and
Water
 36
 What
is
Hydrology?
 •  Defini3on:
The
science
of
water,
its
global
 circulaFon,
distribuFon,
and
properFes,
 specifically
water
at,
near,
or
below
Earth’s
 surface.

 •  Hydrologic
Cycle:
A
simplified
model
of
 the
flow
of
water,
ice,
and
water
vapour
 from
place
to
place.
 Lecture
4
–
Energy
and
Water
 37
 Key
Processes
in
the
Hydrologic
 Cycle
 1.  Precipita3on:
The
condensaFon
of
water
vapour
in
 the
atmosphere
resulFng
in
its
return
to
Earth’s
 surface.
 2.  Evapotranspira3on:
The
release
of
water
into
the
 atmosphere
through
a
combinaFon
of
phase
change
 from
open
surfaces
and
release
of
water
vapour
by
 plants.
 3.  Infiltra3on:
PenetraFon
of
water
through
the
soil
 surface.
 4.  Runoff:
The
flow
of
water
across
or
under
Earth’s
 surface
under
the
force
of
gravity.
 5.  Groundwater
Flow:
The
movement
of
water
beneath
 the
water
table.
 Lecture
4
–
Energy
and
Water
 38
 The
Hydrologic
Cycle
 Lecture
4
–
Energy
and
Water
 39
 Key
Points:
Global
Hydrologic
 Cycle
 1.  More
water
evaporates
from
the
ocean
 than
is
returned
by
precipitaFon.

 2.  More
water
is
returned
to
the
surface
of
 conFnents
by
precipitaFon
than
is
lost
via
 evapotranspiraFon.

 3.  The
imbalance
in
points
#1
and
#2
above
 are
resolved
by
runoff
of
water
from
 conFnents
to
the
ocean.
 Lecture
4
–
Energy
and
Water
 40
 A
Catchy
Tune
 To
help
you
remember
the
water
cycle:
 hVp://www.youtube.com/watch? v=T05djitkEFI&feature=related
 Lecture
4
–
Energy
and
Water
 41
 ...
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