Final answer:
Net photosynthesis, or net primary productivity (NPP), is calculated by subtracting the respiration rate (R) from the photosynthetic carbon fixation rate (P), typically measured in grams of carbon per day.
Step-by-step explanation:
To calculate net photosynthesis, also known as net primary productivity (NPP), one must subtract the respiration rate (R) from the rate of carbon fixation by photosynthesis (P). Both rates can be expressed in grams of carbon per day (gC/d). The formula is NPP = P - R. This represents the amount of carbon that is converted into biomass after accounting for the carbon dioxide released during respiration.
Net primary productivity is essential for understanding the energy flow within an ecosystem because it indicates how much energy is available for the next trophic level, the primary consumers. It is vital for ecological studies and can be considered a measurement of the energy accumulation within an ecosystem.