GGR227H5 Lecture Notes - Lecture 4: Ecosystem Respiration, Carbonate Rock, Lithosphere
Document Summary
Ecosystem productivity: net primary productivity (npp) = gross primary productivity (gpp) - respiration by autotrophs, npp = energy available to consumers and decomposers, net ecosystem productivity (nep) = gpp - ecosystem respiration. Npp: npp = photosynthesis - respiration, canadian ecosystems have low npp, but store most c in soil and biomass. Links the global c and o cycles together. There are 800 gt c as co2 in the atmosphere and if the removal rate of co2 from the atmosphere is 215 gt. Mrt = 3. 7 years = ~ 4 years: allows us to make better predictions and design better strategies/decisions with respect to climate change. Nitrogen cycle: n cycles b/w atmosphere and lithosphere: most importantly via biological activity. Nitrogen fixation: n fixed by archaea and bacteria including cyanobacteria, combine n2 with h to make nh3 and nh4+ Soil bacteria change nh3 and nh4+ to no3: plants can use no3- as nutrients.
