2.3 Flows of Energy and Matter Flashcards
Explain the fate of solar radiation as it reaches Earth.
- reflection from Earths surface: 9%
- reflection from cloud surface: 19%
- reflection by scatter from aerosols or atmospheric particles 3%
- abosorption by clouds: 3%
- absorption by dust and molecules in atmosphere: 17%
41% reaches earth surface
pathways of energy through an ecosystem:
- conversion of light energy to chemical energy
- transfer of chemical energy from one trophic level to another with varying efficiencies
- overall conversion of ultraviolet and visible light to heat energy by an ecosystem
- reradiation of heat energy to the atmosphere
how much energy is available to plants on the surface of the earth
1-4%
how much of sunlight is reflected back to space?
Of the energy reaching the Earth’s surface, about 35% is reflected back into space by ice, snow, water and land.
how to calculate ecological efficiency
(energy used for growth (new biomass)/ energy supplied x 100
productivity definition
the conversion of energy into biomass over a given period of time
primary productivity definition
the gain by producers (autotrophs) in energy or biomass per unit per unit time. Either gross or net productivity
gross primary productivity definition
The total amount of energy fixed (converted to sugars) by plants through photosynthesis.
net primary productivity definition
The remaining energy after respiration, stored as biomass.
- This represents the energy available to consumers (herbivores & decomposers).
NPP calculation
NPP = GPP - R
Gross Secondary Productivity definition
total energy or biomass assimilated by consumers
(also known as assimilation)
GPP calculation
food eaten - fecal loss
secondary productivity definition
the biomass gained by heterotrophic organisms (animals), through feeding and absorption, measured in units of mass or energy per unit area per unit time.
NSP definition
the gain by consumers in energy or biomass per unit area per unit time through absorption after allowing for respiratory losses
NSP calculation
NSP = GSP - R
Maximum sustainability yield definition
the amount of biomass that can be extracted without reducing natural capital of the ecosystem.
- equal to NPP or NSP of a system
- harvesting above = reduction of natural capital = unsustainable
carbon cycle transformations
- fossilisation
- combustion
- respiration
- photosynthesis
carbon cycle transfers
- herbivores feeding on producers
- carnivores feeding on herbivores
- decomposers feeding on dead organic matter
- co2 dissolving from atmosphere in rainwater oceans
carbon cycles storages organic
- organisms
- forests
nitrogen cycle transformations
- nitrogen fixation
- nitrogen fixing bacteria
- death and decomposition
- denitrification
- assimilation
nitrogen fixing bacteria explanation
transforms nitrogen gasses found in roots of plants into ammonium ions
- bacteria converts ammonium into nitrites and nitrates
dentrifying bacteria explanation
converts ammonium and nitrate ions into nitrogen gas
nitrogen cycle transfers
- herbivores feeding on producers
- carnivores feeding on herbivores
- decomposers feeding on dead organic matter
- plants absorbing nitrates through their roots
- excretion
Discuss the impacts of human activity on the carbon cycle
- burning fossil fuels/fire adds co2 into atmosphere
- deforistation -> takes away important carbon store
increased atmospheric co2 by about 40%
Discuss the impacts of human activity on the nitrogen cycle
- Farmers using inorganic fertilisers -> Fertilizers increase nitrogen pollution (eutrophication)
- Burning fossil fuels releases NOₓ -> acid rain.
- livestock: release big amounts of ammonia -> atmopsheric nitrogen pollution
- Draining wetlands for agriculture or urban development -> reduces natural dentrificatoin -> higher nitrate levels in water -> water pollution (eutrophication)
more than doubled amount of nitrogen
carbon cycle storages inorganic
- atmosphere
- soil
- fossil fuels
- ocean
nitrogen cycle storages organic
organisms
nitrogen cycle storages inorganic
- soil
- fossil fuels
- atmosphere
- water bodies
stages nitrogen cycle
1) nitrogen fixation
2) nitrification
3) absorption
4) consumption
5) decomposition
6) denitrifying bacteria
stages carbon cycle
1) release of carbon
2) absorption
3) consumption
4) decomposition
absorption nc
plants absorb nitrates into soil and make proteins
decomposition nc
decomposers break down feaces and dead bodies of organisms -> nitrogen is returned to soil as ammonium ions
Denitrification nc
transforms nitrates into nitrogen
assimilation nc
nitrogen from nitrates used by plants to make protein and ammino acids
why is radiation captured by producers small?
- fails to enter chloroplasts because much light is reflected, transmitted or is the wrong wavelength to be absorbed
- conversion of light to chemical energy is inefficient
what are factors affecting biomass production?
- Spatial variation:
Biomes like tropical rainforests have higher NPP than tundras. - Temporal variation:
Seasonal changes (light, water, temperature) affect productivity.
GSP definition
the total energy taken as food subtracting the mass of faecal loss from the mass of food consumed
