What is cultural eutrophication?

Cultural eutrophication refers to the process where nutrient enrichment in aquatic systems, particularly nitrogen and phosphorus, is significantly accelerated due to human activities. This often results from the runoff of fertilizers from agricultural fields, sewage discharge, and industrial waste, which adds excessive nutrients to water bodies. As a result, this influx leads to rapid algae blooms, which can cause harm to aquatic ecosystems by depleting oxygen levels and blocking sunlight necessary for other aquatic plants.

In contrast, the other options describe aspects that do not align with the definition of cultural eutrophication. A natural increase in nutrient availability does occur in ecosystems but is a part of natural processes rather than a consequence of human actions. A decrease in aquatic plant life might result from eutrophication due to shading by algae, but it does not define the process itself. Finally, a reduction of nutrient levels in water opposes the essence of eutrophication, which is fundamentally about increased nutrient levels. Therefore, the choice highlighting the human-induced acceleration of nutrient availability effectively captures the concept of cultural eutrophication.