ENVS 200 CHAP 11 Flashcards
What is a standing crop?
It is the bodies of living organisms within a unit area, constituting a standing crop of biomass
ex. trees
What is biomass?
It is the mass of organisms per unit area of ground/water, usually expressed in units of energy (ex. joules/sq. m), and dry organic matter (g/sq. m) or mass of carbon (g of C/sq. m).
Basically mass per area that could include all organisms
What is primary productivity?
It is the rate at which biomass is produced per unit are or volume through photosynthesis and can be expressed in many different units (ex. GPP & NPP).
Rate of biomass production per area per time
What is gross primary productivity (GPP)?
It is the total fixation of energy by photosynthesis, but a portion of this as respiratory heat (R auto)
What is respiratory heat (R auto)?
It is a portion of the GPP that is respired away by primary producers and is lost as respiratory heat
What is net primary productivity (NPP)?
It is GPP-R auto and represents the actual rate of new biomass production available for consumption by heterotrophs
What is secondary productivity?
It is the rate of biomass production by heterotrophs
What is net ecosystem productivity (NEP)?
It is the difference between GPP and the respiration of all organisms in an ecosystem (R total). It measures the net rate of accumulation/loss of OM, energy, or organic carbon from an ecosystem and is equivalent to NPP-R het (the respiration of heterotrophic organicms)
What is a live consumer system?
It is when a portion of primary production is consumed by herbivores, which are then consumed by carnivores
What is a decomposer system?
It is the other portion of NPP not eaten by herbivores but by detritivores and decomposers.
Decomposers
an organism (bacteria and fungi) that decomposes organic material
Detritivores
animals that consume dead OM
What is Liebig’s Law of the Minimum?
It states that the growth of a plant is limited primarily by one nutrient that is in relatively short supply (usually N or P). The nutrient that is the most important but least available will control NPP.
ex. tropics are more P-limited (old, weathered soil) and the boreal is more N-limited (young, nutrient-lacking soil)
What is colimitation?
It is when both N and P are limiting to PP.
ex. occurs in temperate forests
What is eutrophication?
It is the process of excess nutrient enrichment and can lead to algal blooms, which are very damaging and deplete ecosystems of oxygen