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Ecosystem• All the organisms in a community plus abiotic
factors–Transform energy & process matter
• Ecosystems are self-sustaining–what is needed?
capture energycapture energytransfer energytransfer energycycle nutrientscycle nutrients
capture energycapture energytransfer energytransfer energycycle nutrientscycle nutrients
biosphere
Ecosystem inputs
constant inputof energy
energy flowsthrough
nutrients cycle
inputsinputs energyenergy nutrientsnutrients
inputsinputs energyenergy nutrientsnutrients
How does energymove through
the ecosystem?
Energy flows through ecosystems
sun
producers (plants)producers (plants)producers (plants)producers (plants)
loss of energy
loss of energy
secondary secondary consumersconsumers(carnivores)(carnivores)
secondary secondary consumersconsumers(carnivores)(carnivores)
primary consumersprimary consumers(herbivores)(herbivores)
primary consumersprimary consumers(herbivores)(herbivores)
5
Primary Productivity
• What is primary productivity?• What is GPP?• What is NPP?• How does the light/dark bottle method allow you to calculate primary productivity?
5
Limiting Factors
What are some limiting Factors that can effect productivity?
Light
Nitrogen
Phosphorous
• Trophic levels–Why do food chains usually go up only 4 or 5 levels?
–all levels connect to decomposers
Food chains
Fungi
Level 4Level 4
Level 3Level 3
Level 2Level 2
Level 1Level 1
Decomposers
Producer
Primary consumer
Secondary consumer
Tertiary consumer
top carnivore
carnivore
herbivore
Bacteria
autotrophsautotrophs
heterotrophsheterotrophs
Inefficiency of energy transfer• Loss of energy between levels of food chain
–Where is the energy that is not available to the next tropic level?
only this energymoves on to the
next level in the food chain 50%
waste (feces)
33%cellularrespiration
energy lost todaily living
energy lost todaily living
17% growth
Ecological pyramid• Loss of energy between levels of food chain
–can feed fewer animals in each level
1,000,000,000
100,000
100
1
Food webs• Food chains are linked together into food webs
• Who eats whom?–a species may weave into web at more than one level• bears• humans
–eating meat?–eating plants?
Humans in food chains• What has more energy a pound of hamburger or a pound of
peas?• What is the most efficient way for one person to eat?• What is the most efficient way for the human population to
eat?
13
Biological Magnification
Why do eggshellsbecome Fragile?
Where doesthe toxin
accumulate?
Let’s go to the video!
biosphere
Nutrients…
nutrients cycle
Don’t forgetthe laws of
Physics!
Matter cannotbe created or
destroyed
General Nutrient
Cycle
Decompositionconnects all
trophic levels
consumerconsumerss
decomposerdecomposerss
abioticabioticreservoireservoi
rr
nutrientsnutrientsmade availablemade availableto producersto producers
geologicgeologicprocesseprocesse
ss
consumerconsumerss
consumer
producer
decomposer
abioticreservor
nutrientsENTER FOOD CHAIN
= made availableto producers
geologicprocesse
return toabiotic
reservoir
Carbon cycleCO2 in
atmosphere
Diffusion RespirationPhotosynthesis
Photosynthesis
Plants and algae
PlantsAnimals
Industry and home
Combustion of fuels
Animals
Carbonates in sediment
Bicarbonates
Deposition ofdead material
Depositionof deadmaterial
Fossil fuels(oil, gas, coal)
Dissolved CO2
abiotic reservoir:CO2 in atmosphereOther reservoirFossil fuelsenter food chain:photosynthesis = carbon fixation in Calvin cyclerecycle:decomposition return to abiotic:respirationcombustion
Birds
Herbivores
Plants
amino acids
CarnivoresAtmospheric
nitrogen
loss to deep sediments
Fish
Plankton withnitrogen-fixingbacteria
Nitrogen-fixingbacteria
(plant roots)
Nitrogen-fixingbacteria
(soil)
Denitrifyingbacteria
Death, excretion, feces
Nitrifying bacteria
soil nitrates
excretion
Decomposing bacteria
Ammonifying bacteria
Nitrogen cycle
abiotic reservoir:N in atmosphereLocal reservoir N in soilenter food chain:nitrogen fixation by soil & aquatic bacteriarecycle:decomposing & nitrifying bacteriareturn to abiotic:denitrifying bacteria
Lakes
Runoff
Percolation in soil
Evaporation
Transpiration
Precipitation
Oceans
Solar energy
AquiferGroundwater
Water cycleWater cycle
Water vapor
abiotic reservoir:surface & atmospheric waterenter food chain:precipitation & plant uptakerecycle:transpirationreturn to abiotic:evaporation & runoff
Phosphorus cycle
Loss to deep sediment
Rocks andminerals
Soluble soilphosphate
Plants andalgae
Plants Urine
Land animals
Precipitates
Aquaticanimals
Animal tissueand feces
Animal tissueand feces
Decomposers(bacteria and
fungi)
Decomposers(bacteria & fungi)
Phosphatesin solution
Loss indrainage
abiotic reservoir:rocks, minerals, soilenter food chain:erosion releases soluble phosphateuptake by plantsrecycle:decomposing bacteria & fungireturn to abiotic:loss to ocean sediment
Breaking the water cycle• Deforestation breaks the water cycle–groundwater is not transpired. Precipitation is not created.
forest forest →→desert desert
desertificationdesertification
Studying ecosystems
• Hubbard Brook Experimental Forest
7800 acres7800 acres
38 acre deforestation38 acre deforestation
Effects of deforestationC
on
cen
trat
ion
of
nit
rate
(m
g/l
)
1965 1966
Year
2
0
4
40
80
1967 1968
Deforestation
nitrate levels in runoffnitrate levels in runoff
40% increase in runoff40% increase in runoffloss of water
40% increase in runoff40% increase in runoffloss of water
60x loss in nitrogen60x loss in nitrogen10x loss in calcium10x loss in calcium
60x loss in nitrogen60x loss in nitrogen10x loss in calcium10x loss in calcium
loss into loss into surface watersurface water
loss out of loss out of ecosystemecosystem!!
Why is nitrogen so Important?