Which type of algae is most likely found in nutrient-rich waters?

Blue-green algae, also known as cyanobacteria, thrive in nutrient-rich waters due to their ability to utilize high levels of nitrogen and phosphorus, which are often found in environments where there is run-off from agricultural areas, wastewater discharge, or other sources of nutrient pollution. These conditions create an ideal environment for blue-green algae to flourish, sometimes leading to harmful algal blooms.

In contrast, while green algae can also be found in nutrient-rich environments, they do not typically dominate in the same way that blue-green algae do under high nutrient conditions. Red algae generally prefer colder, nutrient-poor conditions, and brown algae are more commonly found in marine environments, often in deeper waters with less nutrient pollution. Thus, blue-green algae are particularly significant in discussions about water quality and treatment, especially in relation to the management of nutrient inputs in water bodies.