Final answer:
To reduce algae in a pond, a farmer should reduce the nutrients nitrogen and phosphorus, which are important limiting factors for algae growth. High inputs of these nutrients lead to algal blooms, which can have negative effects on the aquatic ecosystem. These algal blooms reduce light penetration, deplete oxygen, and can cause the death of aquatic organisms.
Step-by-step explanation:
In order to reduce the amount of algae in a pond, a farmer would want to reduce the nutrients nitrogen and phosphorus. These nutrients are important limiting factors in lakes and ponds and are responsible for the growth of algae. When there is a large input of nitrogen and phosphorus, such as from sewage and fertilized lawns and farms, it leads to the growth of algae and the formation of algal blooms. These algal blooms can reduce light penetration in the water, causing other plants to die and resulting in severe oxygen depletion.