Water with different qualities meets through the Strait of Gibraltar

Where do plankton grow more prolifically in the ocean? At fronts where different water masses meet. In this case, less-salty, less-dense water from the Atlantic Ocean enters the Mediterranean Sea, where it meets saltier, denser Mediterranean water. The denser water sinks beneath the lighter water. The lighter water rises toward the sunlit surface, bringing with it nutrients that fuel the growth of plankton. (Illustration by Eric S. Taylor, Tim Silva, and Jack Cook, © Woods Hole Oceanographic Institution)