APES Aquatic Pollution Practice Test 2026 - Free Aquatic Pollution Practice Questions and Study Guide

Cultural eutrophication refers to the process by which water bodies become enriched with nutrients, commonly due to human activities such as agricultural runoff, wastewater discharge, and urban stormwater runoff. This nutrient influx, particularly nitrogen and phosphorus, can lead to accelerated plant growth, including algae blooms.

The increase in algal biomass can raise the biochemical oxygen demand (BOD) in the water. As algae die and decompose, the decomposition process consumes a significant amount of dissolved oxygen, which can lead to hypoxic (low oxygen) conditions often detrimental to aquatic life. This imbalance in oxygen levels can harm fish and other aquatic organisms, resulting in decreased biodiversity and potential die-offs.

Thus, the answer emphasizes the critical relationship between nutrient pollution and oxygen levels in aquatic environments, illustrating how cultural eutrophication can lead to increased BOD.