What is the upward movement of cold water from deeper layers called?

The upward movement of cold water from deeper layers is known as upwelling. This process is driven by a combination of wind patterns and the Earth's rotation, often occurring along coastlines where winds push surface waters away from the shore. As the surface water is displaced, deeper, colder water rises to replace it, bringing with it nutrients that are vital for marine ecosystems. This nutrient-rich water supports the growth of phytoplankton, which forms the base of the oceanic food web and is essential for sustaining fish populations and other marine life.

Upwelling is significant for both ecological productivity and global climate systems, as it influences temperature, ocean circulation, and food availability in marine environments. Other options, such as oceanic ridges, seamounts, and the Coriolis effect, relate to different geological and oceanic processes but do not specifically refer to the upward movement of water from deeper layers.