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)...

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 3.18, it is expressed as units of energy (kilocalories, or kcal) produced in a given area (square meters, or m2) per year. Look again at Figure 3.18 and consider the differences in NPP among various ecosystems. Then answer the following questions:

About how many times higher is NPP in estuaries than it is in lakes and streams? Why do you think this is so?