In a grassland ecosystem, the gross primary productivity (GPPGPPGPP) of the plant community is measured as 4.0×104 kJ m−2 yr−14.0 \times 10^4 \text{ kJ m}^{-2}\text{ yr}^{-1}4.0×104 kJ m−2 yr−1. The plants lose 65% of this energy as heat through cellular respiration.
Primary consumers in this ecosystem ingest 2.8×103 kJ m−2 yr−12.8 \times 10^3 \text{ kJ m}^{-2}\text{ yr}^{-1}2.8×103 kJ m−2 yr−1 of the producer biomass. Of this ingested energy, 1.5×103 kJ m−2 yr−11.5 \times 10^3 \text{ kJ m}^{-2}\text{ yr}^{-1}1.5×103 kJ m−2 yr−1 is lost in faeces and urine, while 6.0×102 kJ m−2 yr−16.0 \times 10^2 \text{ kJ m}^{-2}\text{ yr}^{-1}6.0×102 kJ m−2 yr−1 is lost through cellular respiration.
What is the net secondary productivity (NNN) of the primary consumers expressed as a percentage of the net primary productivity (NPPNPPNPP) of the producers?
1.75%1.75\%1.75%
5.00%5.00\%5.00%
9.29%9.29\%9.29%
20.00%20.00\%20.00%