A rapid and large increase in plankton biomass, often driven by nutrient upwelling or light, is known as what?

• A. Plankter
• B. Plankton
• C. Plankton Bloom
• D. Nekton

Answer: (C)

A bloom describes a rapid, large increase in plankton biomass. When nutrient-rich upwelling brings nutrients into sunlit surface waters, phytoplankton can photosynthesize and multiply quickly, leading to a sharp rise in their population. Light availability is also crucial—more light supports faster growth, so blooms are more likely when days are long and waters are clear. This phenomenon specifically refers to the sudden surge in population size, not just the presence of plankton or larger, swimming animals. Plankter is not the term for this event, while plankton and nekton refer to broader groups of organisms. Blooms can be harmless, but some become harmful algal blooms and can affect oxygen levels and ecosystem health as they rise and then decay.