What is the primary remediation strategy for eutrophication in freshwater systems?

• A. Reducing nutrient inputs to limit algal bloom formation.
• B. Increasing nutrient inputs to balance nutrients.
• C. Focusing on heating lake water to kill algae.
• D. Removing fish to reduce feeding.

Answer: (A)

Eutrophication in freshwater systems is driven by excess nutrients, especially phosphorus and nitrogen, which fuel rapid algal growth and can lead to oxygen depletion. The most effective remediation is to cut nutrient inputs at the source. By reducing runoff from agriculture and urban areas, upgrading wastewater treatment, and implementing practices like buffer strips and proper manure management, the nutrient load entering lakes and rivers drops. With fewer nutrients available, algal blooms lessen, light penetration improves, and oxygen conditions begin to recover, allowing the ecosystem to move toward a healthier state. The other ideas don’t address the root cause: adding nutrients would worsen the problem; heating water to kill algae is impractical and doesn’t prevent new blooms; removing fish targets ecosystem balance rather than the nutrient driver.