Answer and Explanation:
Available Data:
- NPP = GPP – Respiration = 120 grams/m2/day
- NPP= Net primary productivity of a system
- GPP= Gross productivity of the producers
- Respiration loss 25% of NPP
- Insolation energy is 800 calories/cm2/day
- % Efficiency of Photosynthesis = (NPP/Insolation Energy) X 100
1) Find the gross productivity of the sugar beets.
We need to calculate the GPP, which equals NPP - Respiration rate. The respiration loss is 25% of the NPP. This is:
100% NPP--------------- 120 g/m²/day
25% NPP ----------------X = (25 x 120)/100 = 30 g/m²/day
Now that we know the values of NPP and respiration rate, we can calculate the GPP.
GPP = NPP - Respiration
GPP = 120 (g/m²/day) - 30 (g/m²/day)
GPP = 90 g/m²/day
GPP = 0.009 g/cm²/day
2) Using the NPP, calculate the efficiency of photosynthesis for the sugar beets.
% Efficiency of Photosynthesis = (NPP/Insolation Energy) X 100
We know the NPP, but this value is calculated in g/m²/day, while the Insolation energy is in g/cm²/day. We need to calculate the % Efficiency of Photosynthesis in cm. To do that, we must transform the information.
So if 1 m² = 10,000 cm², then:
10,000cm²----------120 grams/m²/day NPP
1 cm²---------------- (1 x 120) / 10,000 = 0.012 grams/cm²/day NPP
We also know that 1 gr beets = 2,000 cal, and that the Insolation energy is 800 calories/cm²/day
So we need to transform Insolation energy from calories/cm²/day to grams/cm²/day, so:
2,000 calories ----------------- 1 gr beet
800 calories/cm²/day---------X = 0.4 gr beet.
% Efficiency of Photosynthesis = (NPP/Insolation Energy) X 100
% Efficiency of Photosynthesis = (0.012 (gr/cm2/day) /0.4 (gr/cm2/day)) X 100
% Efficiency of Photosynthesis = 3 gr/cm2/day
