Algae bloom refers to a rapid growth or increase in the population of algae, which forms visible patches on the surface of water bodies such as lakes, rivers and oceans. These blooms can occur naturally due to favorable environmental conditions like sunlight, warm temperatures, and nutrient-rich waters. However, excessive algal growth can also be caused by human activities such as agricultural runoff or sewage discharge, which introduce high levels of nutrients into the water. Algae blooms are not always harmful but they can have negative impacts on aquatic ecosystems and human health if the excessive algal growth leads to oxygen depletion, contamination of drinking water sources or toxin production by certain species of algae.