What type of water condition can lead to algal blooms?

Algal blooms are a consequence of favorable environmental conditions that promote the rapid growth of algae in water bodies. One of the primary factors that contribute to the occurrence of algal blooms is the presence of sufficient nutrients, particularly nitrogen and phosphorus. When nutrient levels are elevated, typically due to runoff from agricultural activities, wastewater discharges, or other sources, algae can flourish.

Additionally, warm temperatures play a critical role in facilitating algal growth. Warmer conditions can enhance the metabolic rates of algae, allowing them to reproduce more rapidly. Therefore, the presence of both adequate nutrients and optimal temperature conditions creates an environment conducive to algal blooms, making this combination the correct answer.

Considering the other options, high dissolved oxygen generally indicates a balanced and healthy aquatic ecosystem, which might not lead to algal blooms. Low nutrient levels would not support the significant growth of algae, as they require adequate nutrients to proliferate. Thus, both the presence of sufficient nutrients and the correct temperature are crucial for the development of algal blooms, highlighting the importance of nutrient management and temperature control in water bodies to prevent such occurrences.