What does the term 'eutrophication' refer to in water bodies?

The term 'eutrophication' specifically refers to the process where water bodies become enriched with nutrients, particularly nitrogen and phosphorus. This nutrient enrichment often leads to excessive growth of algae, commonly known as algal blooms. These blooms can significantly alter the ecosystem by blocking sunlight from reaching aquatic plants and disrupting normal aquatic life cycles.

As the algal blooms grow and eventually die off, the decomposition process by bacteria consumes considerable amounts of dissolved oxygen in the water. This can result in hypoxic (low oxygen) conditions, which are detrimental to fish and other aquatic organisms. While decreased oxygen levels are an important consequence of eutrophication, they are a result of the initial nutrient increase and subsequent algal bloom. Hence, the primary definition of eutrophication focuses on the high levels of nutrients that drive this phenomenon, making it a fundamental concept in understanding water quality and its management.