28: Energy in Ecosystems
Tophat
In hiking up a mountain you are likely to pass through various community types as you proceed from the low-elevation lands to the summit. This change in community is called
zonation
A trophic cascade is an example of a(n) _____ effect
indirect
Reading: Chapter 19
Primary productivity provides energy for the ecosystem
Concepts
Primary productivity: the rate at which solar or chemical energy is captured and converted into chemical bonds by photosynthesis or chemosynthesis
Gross primary productivity (GPP): the rate at which energy is captured and assimilated by producers in a given area
Net primary productivity: the rate energy is assimilated by producers and converted into producer biomass in a given area
Standing crop: the biomass of producers present in a given area of an ecosystem at a particular moment in time
GPP = NPP + Respiration
Energy basis of the ecosystem
Only a fraction of energy made by primary producers makes it to the top level
Food pyramids inverted in aquatic ecosystems, tertiary consumers bigger than producers
Measurements: gases
6 CO2 + gH20 = C6H12O6 + 6
GPP = NPP + Respiration
Measurements: harvesting
Measurements: remote sensing
The brown food web
some energy lost as heat every step
dead organic matter
detritus
Secondary production
net secondary productivity: the rate of consumer biomass accumulation in a given area
Drivers in terrestrial ecosystems
temperature
precipitation
Nitrogen and Phosphorus
all ecosystems
Silicon and iron
ocean
Solar radiation
ALL
Trophic pyramids
Efficiencies
proportions that help understand ecosystems
Conumption efficiency: the percentage of energy or biomass in a trophic level that is consumed by the next higher trophic level
Assimilation efficiency: the percentage of consumer energy that is assimilated
Net production efficiency: the percentage of assimilated energy that is used for growth and reproduction
Ecological efficiency: the percentage of net production from one trophic level, compared to the next lower tophic level
also known as food chain efficiency
Ecological efficiency and the number of trophic levels
Residence times
the length of time that energy remains in a given trophic level
decomposition rates are higher in tropical ecosystems bc of temperature/humidity
Stoichiometry: the study of the balance of nutrients in ecological interactions such as between a herbivore and a plant
Tophat
In hiking up a mountain you are likely to pass through various community types as you proceed from the low-elevation lands to the summit. This change in community is called
zonation
A trophic cascade is an example of a(n) _____ effect
indirect
Reading: Chapter 19
Primary productivity provides energy for the ecosystem
Concepts
Primary productivity: the rate at which solar or chemical energy is captured and converted into chemical bonds by photosynthesis or chemosynthesis
Gross primary productivity (GPP): the rate at which energy is captured and assimilated by producers in a given area
Net primary productivity: the rate energy is assimilated by producers and converted into producer biomass in a given area
Standing crop: the biomass of producers present in a given area of an ecosystem at a particular moment in time
GPP = NPP + Respiration
Energy basis of the ecosystem
Only a fraction of energy made by primary producers makes it to the top level
Food pyramids inverted in aquatic ecosystems, tertiary consumers bigger than producers
Measurements: gases
6 CO2 + gH20 = C6H12O6 + 6
GPP = NPP + Respiration
Measurements: harvesting
Measurements: remote sensing
The brown food web
some energy lost as heat every step
dead organic matter
detritus
Secondary production
net secondary productivity: the rate of consumer biomass accumulation in a given area
Drivers in terrestrial ecosystems
temperature
precipitation
Nitrogen and Phosphorus
all ecosystems
Silicon and iron
ocean
Solar radiation
ALL
Trophic pyramids
Efficiencies
proportions that help understand ecosystems
Conumption efficiency: the percentage of energy or biomass in a trophic level that is consumed by the next higher trophic level
Assimilation efficiency: the percentage of consumer energy that is assimilated
Net production efficiency: the percentage of assimilated energy that is used for growth and reproduction
Ecological efficiency: the percentage of net production from one trophic level, compared to the next lower tophic level
also known as food chain efficiency
Ecological efficiency and the number of trophic levels
Residence times
the length of time that energy remains in a given trophic level
decomposition rates are higher in tropical ecosystems bc of temperature/humidity
Stoichiometry: the study of the balance of nutrients in ecological interactions such as between a herbivore and a plant