Environmental Science 15th Edition by Scott Spoolman,Tyler Miller

تمرين 14

Recall that net primary productivity (NPP) is the rate at which producers can make the chemical energy that is stored in their tissues and that is potentially available to other organisms (consumers) in an ecosystem. In Figure 3.15, it is expressed as units of energy (kilocalories, or kcal ) produced in a given area (square meters, or m 2) over a period of time (a year). Look again at Figure 3.12 and consider the differences in NPP among various ecosystems. Then answer the following questions:
About how many times more NPP do estuaries produce, compared to lakes and streams? Why do you think this is so?