10- energy transfer through ecosystems Flashcards
NPP =
GPP - R
gross primary productivity (GPP)
The total rate at which solar energy is converted to chemical energy by photosynthesis in green plants over a given area and time.
net primary productivity (NPP)
The rate of energy storage in plant biomass after subtracting the energy plants use for respiration (R) from GPP.
importance of NPP
• Indicates the amount of energy available to herbivores and higher trophic levels.
• Determines the carrying capacity of ecosystems for herbivorous consumers.
• High NPP areas are crucial for supporting diverse and abundant wildlife.
• Management practices may aim to preserve or enhance NPP for ecosystem health.
efficiency of energy transfer =
what is efficiency of energy transfer
Only a fraction of energy (usually around 10%) is transferred to the next trophic level.
how is energy lost
• Respiration.
• Heat.
• Waste.
• Uneaten parts.
• Other biological processes.
how is matter / biomass lost
• CO2 due to respiration.
• Waste.
• Uneaten parts.
draw the carbon cycle
carbon cycle- photosynthesis
• CO2 is used up in photosynthesis.
• Carbon dioxide is absorbed by producers to make carbohydrates in photosynthesis.
carbon cycle- respiration
• Animals produce CO2 during respiration.
• Animals feed on plants, passing the carbon compounds along the food chain. Most carbon they consume is exhaled as carbon dioxide during respiration. The animals and plants eventually die.
carbon cycle- decomposition
• Decomposers produce CO2.
• Dead organisms are decomposed and the carbon in their bodies is returned to the atmosphere as carbon dioxide during decomposition.
carbon cycle- combustion
• CO2 is released by burning fossil fuels (remains of dead organisms).
• In some conditions decomposition is blocked. The plant and animal material may then be available as fossil fuel in the future for combustion.
draw the nitrogen cycle
nitrogen cycle- nitrogen fixation
• Nitrogen gas cannot be directly used by plants and animals.
• Nitrogen fixing bacteria convert nitrogen gas into ammonia, then ammonium ions.
nitrogen cycle- nitrification
• Nitrifying bacteria convert ammonium ions into nitrites, then nitrates.
• This happens quickly in well aerated soil.
nitrogen cycle- assimilation and feeding
• Nitrate ions are transported from soil to plant roots.
• Plants use the nitrate to form nitrogen-containing compounds (nucleic acids, proteins).
• Through feeding, animals gain the nitrate.
nitrogen cycle- decomposition
Decomposers convert nitrogen-containing compounds into simpler forms.
nitrogen cycle- ammonification
Ammonification occurs, producing ammonia, then ammonium ions.
nitrogen cycle- denitrification
• Denitrifying bacteria convert nitrate back to nitrogen gas.
• This happens in poorly aerated soil with anaerobic conditions.
