Question

Which best explains eutrophication as a cause of dead zones?

a) It results from decreased nutrient levels, suffocating marine life
b) It stems from excess nutrients, causing algal blooms and oxygen depletion
c) It occurs due to reduced sunlight penetration, hindering photosynthesis
d) It arises from increased dissolved oxygen, harming aquatic organisms

Answer 1

Eutrophication leads to dead zones by causing excess nutrients to flow into water bodies, which spurs algal growth and depletes oxygen, harming marine life.

Step-by-step explanation:

The correct explanation for eutrophication as a cause of dead zones is that it stems from excess nutrients, leading to algal blooms and consequent oxygen depletion in the water. This occurs when excess phosphorus and nitrogen from sources such as fertilizer runoff and sewage enter aquatic ecosystems, causing an excessive growth of algae. The death and decay of these organisms deplete the dissolved oxygen needed by aquatic organisms like shellfish and finfish, ultimately resulting in a dead zone.

Eutrophication leads to dead zones by causing excess nutrients to flow into water bodies, which spurs algal growth and depletes oxygen, harming marine life.