Answer: 150 joules per square meter per year
Step-by-step explanation:
To calculate the Net Primary Productivity (NPP) of an ecosystem, you can use the following formula:
NPP = Gross Primary Productivity (GPP) - Respiration Loss
In this case, you're given:
GPP = 600 J/m²/year
Respiration Loss = 450 J/m²/year
Now, simply subtract the respiration loss from the gross primary productivity:
NPP = 600 J/m²/year - 450 J/m²/year
NPP = 150 J/m²/year
The Net Primary Productivity (NPP) of the ecosystem is 150 joules per square meter per year. This represents the energy that is available for consumption by herbivores and other trophic levels in the ecosystem after the energy lost to respiration by the producers.