What initiates eutrophication according to the material?

What initiates eutrophication according to the material?

• A. Nutrients entering the water
• B. Algal blooms
• C. Oxygen depletion
• D. Increased water temperature

Answer: (A)

Nutrient inputs into a water body trigger eutrophication. When nutrients like nitrogen and phosphorus enter lakes or streams—often from fertilizer runoff, sewage, or decomposing organic matter—they feed rapid growth of algae and aquatic plants. This nutrient-driven bloom reduces light penetration and, as the organisms die, their decomposition uses up dissolved oxygen, leading to oxygen depletion and stress or death of aquatic life. Increased water temperature can speed up these processes and worsen effects, but it does not start eutrophication by itself; the initial trigger is the addition of nutrients.

Nutrient inputs into a water body trigger eutrophication. When nutrients like nitrogen and phosphorus enter lakes or streams—often from fertilizer runoff, sewage, or decomposing organic matter—they feed rapid growth of algae and aquatic plants. This nutrient-driven bloom reduces light penetration and, as the organisms die, their decomposition uses up dissolved oxygen, leading to oxygen depletion and stress or death of aquatic life. Increased water temperature can speed up these processes and worsen effects, but it does not start eutrophication by itself; the initial trigger is the addition of nutrients.