What is eutrophication?

Eutrophication refers specifically to the process of nutrient enrichment in water bodies, mainly due to an increase in nutrients, particularly nitrogen and phosphorus. This enrichment often stems from agricultural runoff, wastewater discharge, or the use of fertilizers, which promotes the growth of algae and aquatic plants. As these organisms thrive, they can lead to excessive algal blooms, which may deplete oxygen levels in the water as they die and decompose. This can create conditions that are detrimental to aquatic life, resulting in "dead zones" where fish and other organisms cannot survive.

The other choices do not accurately capture the essence of eutrophication. Filtering water is a separate treatment process aimed at removing contaminants, while techniques for measuring pollution levels focus on assessing water quality rather than the enrichment process itself. The natural process of water evaporation does not involve nutrient dynamics and is unrelated to the concept of eutrophication. Understanding eutrophication is crucial in surface water quality management as it has significant ecological impacts and can influence water health and usability.