Energy and Matter Fluxes Flashcards
differences between energy and matter supply to organisms
“energy is dissipated as heat and replaced by solar radiation - needs this ‘outside’ energy supply
matter is not lost, but is recyclable. However, it cannot be used by more than one organism at a time - needs decomposition to make matter available as nutrients”
life-based energy fluxes
photosynthesis, albedo (from lack of vegetation)
life-based matter fluxes
“hydrological cycle
carbon cycle
N, P, S cycling (global biogeochemical cycles)”
what is GPP
gross primary productivity = total amount of glucose produced by photosynthesis in a given area
what is NPP
“net primary productivity = GPP - glucose lost by respiration
the carbon that gets assimilated into the plant”
basic explanation of carbon cycle
“photosynthesis, carbon intake as co2
carbon used to produce woody material in trees
carbon lost to soil
tree decomposes and releases co2 as it decomposes”
traditional top down method of estimating GPP
eddy covariance/micrometeorological estimates - set up equipment above forest, measuring volume of co2 passing the sensor every second, take records over long time, average it for GPP
biases of eddy covariance
co2 released by photosynthesis, which doesn’t happen at night, but respiration still does. Doesn’t measure this.
traditional bottom up method of estimating GPP
take growth inventories to measure NPP and use chambers to measure co2 leaving (respiration) and add them together
how are satellites now used to estimate GPP
“photosynthesis energy absorbance causes a small fluorescence that satellites can measure on large scales
or measure greenness of plants - amount of chlorophyll to estimate production”
how is NPP estimated
inventory, empirical model simulation, biogeochemical model simulation, dynamic global vegetation model simulation remote sensing estimation
how is inventory used to estimate global NPP
combine observation data from each biome
how do empirical models simulate estimates of global NPP
correlate field NPP data with environmental parameters such as rainfall or temperature
how do biogeochemical models simulate estimates of global NPP
create ecosystem-scale carbon cycle models
how do dynamic global vegetation models simulate estimates of global NPP
ecosystem scale vegetation structure change and carbon cycle models
how does remote sensing estimate global NPP
senses absorbed solar radiation, and uses it to solve for NPP
why is NPP increasing globally
“we use more fertilizer, so more nitrogen
more co2 in the air
longer growing seasons bc climate change”
how much global NPP is appropriated by humans
25%
what are the most productive ecosystems
tropical rainforests, estuaries, swamps and marshes
why is there more matter in a forest than its productivity
some NPP is fixed as wood, which stays there for as long as the tree s alive
where is soil carbon highest globally
temperate areas, where colder temperatures slow the decomposition processes, slowing its release as co2, sometimes storing it as peat
what is a detritivore
organism that breaks detritus into smaller pieces e.g. worm
what is a decomposer
organism that uses enzymes to break detritus into simple inorganic substances e.g. certain bacteria or fungi
3 factors effecting amount of energy transferred from one trophic level to the next
consumption efficiency, assimilation efficiency, production efficiency
