Researchers are measuring surface salinity in different areas of an ocean. Which area will researchers most likely find the highest surface salinity?

• A. An area where warm, dry winds cause a high rate of evaporation
• B. An area with heavy rainfall
• C. A region with strong river inflow
• D. A zone with low surface temperatures

Answer: (A)

Salinity reflects the balance between water loss from evaporation and addition of fresh water from rain or rivers. When winds are warm and dry, evaporation is high, so water leaves as vapor and the remaining seawater becomes richer in salts. There’s little fresh water coming in to dilute it, so salinity climbs. In contrast, heavy rainfall or strong river inflow adds fresh water that dilutes salinity, and cooler conditions typically reduce evaporation, not increase it. So the area with warm, dry winds and high evaporation is the region where surface salinity will be the highest.