Cold, dense water formed in the Arctic that flows onto the floor of the North Atlantic Ocean is called?

• A. Surface Current
• B. La Nina
• C. North Atlantic Deep Water
• D. Thermohaline Circulation

Answer: (C)

Cold, dense water forms when polar waters become very cold and saline enough to increase their density. In the Arctic and subpolar North Atlantic, this dense water sinks and flows along the ocean floor, spreading as bottom water. That bottom water mass is called North Atlantic Deep Water. It’s a key part of the global deep-ocean circulation, helping to drive the larger thermohaline circulation that moves water around the world.

Surface currents are movements near the surface driven mainly by winds, so they don’t describe the deep, bottom water here. La Niña is an atmospheric-ocean pattern in the Pacific and isn’t about deep-water formation in the Atlantic. Thermohaline Circulation refers to the global system that transports water due to density differences, of which North Atlantic Deep Water is a major component; the question asks for the name of the specific water mass, which is North Atlantic Deep Water.