Final answer:
The net primary productivity of a tropical forest where photosynthesis captures 5,000 Joules (J) of energy per square meter per year, with 60 percent lost to respiration, is 2,000 J/m²/year.
Step-by-step explanation:
In a productive tropical forest, photosynthesis by plants captures 5,000 Joules (J) of energy per square meter per year. Since approximately 60 percent of this energy is lost during plant respiration, we calculate the net primary productivity by subtracting the energy used for respiration from the gross productivity. Here's the calculation:
Gross Primary Productivity (GPP) = 5,000 J/m²/year
Energy lost to respiration = 60% of 5,000 J = 0.60 × 5,000 J = 3,000 J/m²/year
Net Primary Productivity (NPP) = GPP - Energy lost to respiration
NPP = 5,000 J - 3,000 J = 2,000 J/m²/year
Therefore, the net primary productivity of this tropical forest is 2,000 J/m²/year, which is the energy available to the primary consumers at the next trophic level after accounting for the respiratory losses of the producers.