Solar radiation of 15000 kcal/m2 yr reaches a meadon. Producers uses 80% of their energy in cellular respiration and supply a net primary productivity of 30000 cal/m2 over a year. what if the efficiency of photosynthesis in this region?

Question

anonymous · Answer

please help, very confused. there are many examples that are like this on my practice worksheet. and i want to figure out how to do it so i can do the rest

anonymous · Answer

the answer is 1% but how do you get it?

koikkara · Answer

Given, Solar radiation= $ 15000 kcal/m^2$
 $80⁄100$ Energy, productivity = $30000 cal/m^2$

koikkara · Answer

@lordofpens formula ?

anonymous · Answer

useful energy divided by input energy

so usually, to find photosynthesis eff i would do

GPP/15000 but i dont know the GPP

koikkara · Answer

. > Gross primary production (GPP) = All CO2 fixed by the plant in photosynthesis
        > Respiration = R
R = CO2 lost from metabolic activity
Rp = Respiration by Plants
Rh = Respiration by Heterotrophs
Rd = Respiration by Decomposers
        >Net Primary Production = NPP = GPP - Rp
        >Net Ecosystem Production = NEP = GPP - (Rp + Rh + Rd)

@lordofpens

koikkara · Answer

Ref: http://www.globalchange.umich.edu/globalchange1/current/lectures/kling/energyflow/EnergyFlow_lecture_large.pdf

koikkara · Answer

here, NPP= 30,000
         GPP= be X
         Rp  = 80% (Energy)

Find, GPP ?? where, NPP = GPP - Rp