IGCSE Environmental Management Practice Test 2026 – Comprehensive All-in-One Guide to Exam Success!

A rapid growth of algae in water is called an algae bloom. This term describes a sudden, dense increase that can color the water and block light, making it the standard way scientists describe such events. The option uses the plural noun form with bloom, which aligns with how the phenomenon is commonly named in environmental science. While similar concepts exist, terms like surge or proliferation aren’t the conventional labels for a bloom of algae, and algal bloom is also a widely recognized variant, but the wording here matches the given answer. This rapid increase is often driven by warm conditions and an excess of nutrients, and it can lead to problems such as oxygen depletion when the algae die and decompose, or toxin production in harmful blooms.