KETAHANAN EKO- SISTEM Produktivitas smno.psdl-ppsub.2013

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smno.psdl-ppsub.2013

ECOSYSTEM PRODUCTIVITY

Food webs, food chains, pyramids – you can also look at ecosystems through

their productivity.

Productivity is the rate at which chemical energy is produced in an ecosystem – expressed as ‘gram of

organic matter per square metre per year’

. Sumber: lynclarkson.wikispaces.com/.../4.+ECOSYSTEMS+DIFER+IN+...………… diunduh 19/12/2012

PRODUKTIVITAS EKOSISTEM

1.Gross primary productivity (GPP) is the rate at which an ecosystem's producers convert solar energy into chemical energy as biomass.

2. Net primary productivity (NPP) is the rate at which energy for use by consumers is stored in new biomass.

NPP = GPP – R [rate at which producers use biomass]


PRODUKTIVITAS PRIMER EKOSISTEM

Generally ecosystems with the highest net productivity are those with the greatest accumulated producer biomass

The higher the net primary production of an ecosystem, the more food is available for consumer organisms and the greater the biomass of consumers living in that ecosystem.

More

producer biomass

More

photosynthes

is

More

chemical

energy stored in

organic matter


PRODUKTIVITAS EKOSISTEM

WHY DO PRODUCTION RATES DIFFER?

1. Why does a desert ecosystem have a lower productivity than a tropical rainforest?

2. What affects do temperature and hours of sunlight have on productivity?

3. List some limiting factors for ecosystems?

4. Explain why Australia does not have rich fishing grounds near its coast.


AN ECOSYSTEM IN DARKNESS

1. If light is needed for photosynthesis, but does not penetrate to the depths of the ocean, how does a consumer in ocean darkness feed?

2. Explain how producers can exist in the dark depths of the ocean.

3. Explain the difference between photosynthetic organisms and chemosynthetic organisms.

4. What is the energy source for photosynthetic organisms? What is the waste product?

5. What is the energy source for chemosynthetic organisms? What is the waste product?


KEY ENERGY PROCESSES

• Photosynthesis: use of chlorophyll. Energy storing process.

– 6 CO2 + 6 H2O + solar energy C6H12O6 + 6 O2

• Cellular Respiration:– Aerobic Respiration: energy releasing

process.– C6H12O6 + 6 O2 6CO2 + 6 H2O + energy

(ATP)• Anaerobic Respiration

– Ex. Fermentation: energy releasing process used by yeast and bacteria


PRIMARY PRODUCTION AND ENERGY FLOW

ENERGY FLOWS: solar (or nuclear) input

heat outputNUTRIENTS RECYCLE: mass conservation

inorganic ↔ organic

. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012

TINGKAT TROFIK

• Trophic Level: Position in a food web determined by number of energy transfers from primary producers to current level:

– Primary producers occupy first level.– Primary consumers occupy second level.– Secondary consumers occupy third level.– Tertiary consumers occupy fourth level.



PRODUSEN – KONSUMEN


RANTAI MAKANAN


RANTAI MAKANAN

• Primary production: Fixation of energy by autotrophs in an ecosystem.– Rate of primary production: Amount of

energy fixed over a given period of time.

• Gross primary production: Total amount of energy fixed by autotrophs.

• Net primary production: Amount of energy leftover after autotrophs have met their metabolic needs.


PRODUKSI PRIMER

• Bottom-Up Controls– Influences of physical and chemical

factors of an ecosystem.

• Top-Down Controls– Influences of consumers.


KONTROLPRODUKSI PRIMER

Actual Evapotranspiration and Terrestrial Primary

Production

• Rosenzweig estimated influence of moisture and temperature on rates of primary production by plotting relationship between annual net primary production and annual actual evapotranspiration (AET).– AET: Annual amount of water that

evaporates and transpires off a landscape.

• Cold dry ecosystems tend to have low AET.


Evapotranspiration and Terrestrial Primary Production



PRODUKSI PRIMER NETO

• Significant variation in terrestrial primary production can be explained by differences in soil fertility.– Shaver and Chapin found arctic net primary

production was twice as high on fertilized plots as unfertilized plots.

– Bowman suggested N is main nutrient limiting net primary production in a dry tundra meadow, and N and P jointly limit production in a wet meadow.


PRODUKSI PRIMER & KESUBURAN TANAH


PRODUKSI PRIMER NETO


PRODUKSI PRIMER

POLA PRODUKSI PRIMER AKUATIK

• Several studies have found quantitative relationship between phosphorus and freshwater phytoplankton biomass.

• Several studies support generalization that nutrient availability controls rate of primary production in freshwater ecosystems.



PRODUKSI PRIMERBIOMASA ALGAE

Carpenter proposed piscivores and planktivorous fish can cause significant deviations in primary productivity.

– Carpenter and Kitchell proposed the influence of consumers on lake primary productivity propagate through food webs.

• Trophic Cascade Hypothesis


PRODUKSI PRIMERDANAU







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KETAHANAN EKO- SISTEM Produktivitas smno.psdl-ppsub.2013