Final answer:
Primary productivity contributes to bottom-up control in ecosystems by determining nutrient availability and controlling the flow of energy and nutrients from the bottom to the top of the trophic pyramid.
Step-by-step explanation:
Primary productivity is a measure of the rate at which photosynthetic producers incorporate energy from the sun. It contributes to the notion of bottom-up control in ecosystems by determining nutrient availability. When primary producers, such as plants, algae, and photosynthetic bacteria, incorporate energy from the sun through photosynthesis, they also take up nutrients from the environment. These nutrients then become available to other organisms in the food web, setting the foundation for the entire ecosystem. Therefore, primary productivity plays a crucial role in controlling the flow of energy and nutrients from the bottom to the top of the trophic pyramid.