How is the productivity of an ecosystem measured?

The productivity of an ecosystem is most accurately measured by the percentage of energy entering the ecosystem that is converted into biomass. Biomass refers to the total mass of living matter within a given area, and it indicates how much energy is available to consumers in the food chain. This conversion is primarily influenced by photosynthesis, where autotrophs (such as plants) capture sunlight and convert it into chemical energy stored in their biomass. By assessing how efficiently energy is converted into biomass, scientists can evaluate the productivity of different ecosystems and understand their overall health and sustainability.

Other options, while related to ecosystem functioning, do not directly measure productivity. The total amount of sunlight received speaks to potential energy availability rather than how much of that energy is used. The variety of organisms present indicates biodiversity but does not quantify energy conversion. Similarly, the rate of energy loss among trophic levels provides insight into energy transfer efficiency but does not directly assess how much of the energy is transformed into biomass, which is the core aspect of measuring productivity.