Upwellings bring nutrients from deep layers to the surface, supporting marine life. Which statement best describes their effect?

• A. They decrease productivity
• B. They increase productivity
• C. They have no effect
• D. They increase salinity

Answer: (B)

Upwelling brings nutrient-rich deep water into the sunlit surface layer, where phytoplankton can use those nutrients to grow. When nutrients are available, phytoplankton blooms occur, supporting more zooplankton and then more fish and other marine life. This increase at the base of the food web leads to higher overall productivity in the area. So, describing an increase in productivity matches what actually happens when upwelling brings nutrients upward. It’s not about a lack of effect, a decrease, or salinity as the main outcome—the key impact is the boost to biological productivity due to the added nutrients.