Net Primary Production (NPP) in ecosystems can be controlled
either by limiting resources for photosynthetic (autotroph)
organisms, such as nutrients, light, and temperature, or by the
abundance of herbivores (primary consumers), which in turn may be
controlled by predators (secondary consumers). The first scenario
is called bottom-up control of NPP and the second top-down
control.
Consider the saltwater ecosystem. Define the three important
trophic levels. What are the most important photosynthetic
organisms, herbivores, and carnivores in the saltwater
ecosystem?
Outline...