Chapter 54 Ecosystems. I. Energy Flow and Chemical Cycling Energy transfer and thermodynamics...
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Transcript of Chapter 54 Ecosystems. I. Energy Flow and Chemical Cycling Energy transfer and thermodynamics...
Chapter 54Chapter 54
EcosystemsEcosystems
I. Energy Flow and Chemical I. Energy Flow and Chemical CyclingCycling
Energy transfer and thermodynamicsEnergy transfer and thermodynamics– Converting energy and energy lossConverting energy and energy loss– Chemicals are recycledChemicals are recycled
Trophic relationshipsTrophic relationships– Primary producersPrimary producers– Primary consumersPrimary consumers– Secondary consumersSecondary consumers– Detritivores/DecomposersDetritivores/Decomposers
LE 54-2
Microorganismsand other
detritivores
Tertiaryconsumers
Secondaryconsumers
Detritus Primary consumers
Sun
Primary producers
Heat
Key
Chemical cycling
Energy flow
II. Limits to Primary ProductionII. Limits to Primary Production
Gross Primary Productivity (GPP)Gross Primary Productivity (GPP)
Net Primary ProductivityNet Primary Productivity– NPP = GPP – RNPP = GPP – R– Measured as energy per unit area per unit Measured as energy per unit area per unit
time or biomass (newly produced)time or biomass (newly produced)
LE 54-4
Open oceanContinental shelf
Upwelling zonesExtreme desert, rock, sand, ice
Swamp and marshLake and stream
Desert and semidesert scrubTropical rain forest
Temperate deciduous forestTemperate evergreen forest
Tropical seasonal forest
SavannaCultivated land
EstuaryAlgal beds and reefs
Boreal forest (taiga)Temperate grassland
Woodland and shrublandTundra
0.40.4
1.01.31.51.61.71.82.42.72.93.33.54.7
0.30.10.1
5.265.0
Freshwater (on continents)
Terrestrial
Marine
Key Percentage of Earth’ssurface area
Average net primaryproduction (g/m2/yr)
6050403020100 2,5002,0001,5001,0005000
Percentage of Earth’s netprimary production
2520151050
125
2,500
3601,500
5003.090
900600
800
2,200
600
250
1,6001,2001,300
2,000
700140
0.3
7.99.19.6
5.43.5
0.67.1
4.93.8
2.3
24.45.6
1.20.9
0.10.040.9
22
Limitations to NPPLimitations to NPP
In marine and freshwaterIn marine and freshwater– Light limitationsLight limitations– Nutrient limitations – limiting nutrients (Fig. Nutrient limitations – limiting nutrients (Fig.
54.6, p. 1189)54.6, p. 1189)EutrophicationEutrophication
In terrestrial and wetlandsIn terrestrial and wetlands– Actual evapotranspirationActual evapotranspiration
LE 54-6
Atlantic Ocean
ShinnecockBay
Moriches Bay
Long Island
2
45
30
1115
19
21
Coast of Long Island, New York
Great South Bay
Phytoplankton
Inorganicphosphorus
GreatSouth Bay
MorichesBay
ShinnecockBay
Station number2119153011542
8
5
4
3
21
0
6
78
5
4
3
21
0
6
7
Phytoplankton biomass and phosphorus concentration
Ph
yto
pla
nk
ton
(mil
lio
ns
of
cel
ls/m
L)
Ino
rga
nic
ph
os
ph
oru
s(µ
m a
tom
s/L
)
Ammonium enriched
Station number2119153011542
30
Ph
yto
pla
nk
ton
(mil
lio
ns
of
cel
ls p
er m
L)
Startingalgal
density
Phytoplankton response to nutrient enrichment
24
18
12
6
0
Phosphate enrichedUnenriched control
LE 54-9
Control
August 1980JulyJune00
100
200
300L
ive,
ab
ove
-gro
un
d b
iom
ass
(g d
ry w
t/m
2 )
50
150
250N + P
N only
P only
Energy Transfer EfficiencyEnergy Transfer Efficiency
Secondary productionSecondary production
Production efficiency - % not used for Production efficiency - % not used for respirationrespiration
Trophic efficiencies and pyramidsTrophic efficiencies and pyramids– Pyramid of production (Energy)Pyramid of production (Energy)– Pyramid of biomassPyramid of biomass– Pyramid of numbersPyramid of numbers
LE 54-10
Growth (new biomass)
Cellularrespiration
Feces100 J
33 J
67 J
200 J
Plant materialeaten by caterpillar
LE 54-11
1,000,000 J of sunlight
10,000 J
1,000 J
100 J
10 JTertiaryconsumers
Secondaryconsumers
Primaryconsumers
Primaryproducers
LE 54-12a
Trophic level Dry weight(g/m2)
Tertiary consumers
Secondary consumers
Primary consumers
Primary producers
1.5
11
37
809
Most biomass pyramids show a sharp decrease in biomass at successively higher trophic levels, as illustrated by data from a bog at Silver Springs, Florida.
LE 54-12b
Trophic level Dry weight(g/m2)
Primary consumers (zooplankton)
Primary producers (phytoplankton)
21
4
In some aquatic ecosystems, such as the English Channel, a small standing crop of primary producers (phytoplankton) supports a larger standing crop of primary consumers (zooplankton).
LE 54-13
Trophic level Number ofindividual organisms
Tertiary consumers
Secondary consumers
Primary consumers
Primary producers
3
354,904
708,624
5,842,424
LE 54-14
Trophic level
Secondary consumers
Primary consumers
Primary producers
IV. Biogeochemical CyclesIV. Biogeochemical Cycles
See figure 54.18, p.1198See figure 54.18, p.1198
Water cycleWater cycle
Carbon cycleCarbon cycle
Nitrogen cycleNitrogen cycle
Phosphorus cyclePhosphorus cycle
LE 54-16
Fossilization
Reservoir a Reservoir b
Reservoir c Reservoir d
Organicmaterialsavailable
as nutrients
Organicmaterialsunavailableas nutrients
Inorganicmaterialsavailable
as nutrients
Inorganicmaterialsunavailableas nutrients
Livingorganisms,detritus
Coal, oil,peat
Atmosphere,soil, water
Mineralsin rocks
Assimilation,photosynthesis Burning
of fossil fuels
Weathering,erosion
Formation ofsedimentary rock
Respiration,decomposition,excretion
LE 54-17a
Transportover land
Precipitationover landEvaporation
from oceanPrecipitationover ocean
Net movement ofwater vapor by wind
Solar energy
Evapotranspirationfrom land
Runoff andgroundwater
Percolationthroughsoil
LE 54-17b
Cellularrespiration
Burning offossil fuelsand wood
Carbon compoundsin water
Photosynthesis
Primaryconsumers
Higher-levelconsumers
Detritus
Decomposition
CO2 in atmosphere
LE 54-17c
Assimilation
N2 in atmosphere
DecomposersNitrifyingbacteria
Nitrifyingbacteria
Nitrogen-fixingsoil bacteria
Denitrifyingbacteria
NitrificationAmmonification
Nitrogen-fixingbacteria in rootnodules of legumes
NO3–
NO2–NH4
+NH3
LE 54-17d
Sedimentation
Plants
Rain
Runoff
Weatheringof rocks
Geologicuplift
SoilLeaching
Decomposition
Plant uptakeof PO4
3–
Consumption
LE 54-18
Nutrientsavailable
to producers
Decomposers
Geologicprocesses
Abioticreservoir
Consumers
Producers
V. Human Disruption on CyclesV. Human Disruption on Cycles
Nutrient enrichmentNutrient enrichment– Agriculture and nitrogen cyclingAgriculture and nitrogen cycling
criticial load in aquatic ecosystems criticial load in aquatic ecosystems cultural cultural eutrophicationeutrophication
Acid precipitationAcid precipitation
Toxins and biological magnificationToxins and biological magnification
Rising atmospheric CORising atmospheric CO22
Depletion of ozoneDepletion of ozone
LE 54-21
North America
Europe
4.3 4.6
4.14.3
4.6
4.34.6
4.6
LE 54-23
Zooplankton0.123 ppm
Phytoplankton0.025 ppm
Lake trout4.83 ppm
Smelt1.04 ppm
Herringgull eggs124 ppm
Co
nc
en
tra
tio
n o
f P
CB
s
LE 54-24
Temperature
CO
2 c
on
ce
ntr
ati
on
(p
pm
)
CO2
1.05
Te
mp
era
ture
va
ria
tio
n (
°C)
0.90
0.75
0.60
0.45
0.30
0.15
0
–0.15
–0.30
–0.45
390
380
370
360
350
340
330
320
310
3001960 1965 1970 1975 1980 1985 1990 1995 2000 2005
Year
LE 54-26
Ozo
ne
la
ye
r th
ick
ne
ss
(D
ob
so
n u
nit
s)
350
300
250
200
150
100
50
01960 1965 1970 1975 1980 1985 1990 1995 2000 2005
Year (Average for the month of October)
1955
LE 54-27
Chlorine atoms
O3Chlorine
Cl2O2
CIO
O2
O2
CIO
Chlorine from CFCs interacts with ozone (O3), forming chlorine monoxide (CIO) and oxygen (O2).
Sunlight causes Cl2O2 to break down into O2 and free chlorine atoms. The chlorine atoms can begin the cycle again.
Two CIO molecules react, forming chlorine peroxide (Cl2O2).
Sunlight