In the depths of the ocean, tectonic plates can move around and create mountain ranges called mid-ocean ridges. Volcanoes and underwater chimneys can also be created in seas and oceans.
On the ocean floor huge plates can crash into each other, creating giant mountains. Plates can also pull away from each other, which creates large bodies of water. If they pull away from each other quickly, it will form rounded ridges. If they pull away from each other slowly, deep mountain ridges are formed instead. When the plates spread, they can also cause seas, oceans, or even underwater mountains.
Underwater volcano activity can occur several meters beneath a valley. These volcanoes only erupt periodically. The convention currents in Earths’ mantle controls the ridge system and brings magma up to the surface.
Underwater chimneys spew out hot, black water. The water has energy-rich minerals. Colonies of microscopic bacteria eat these minerals, supporting the ecosystem of tubeworms, blind crabs, and other rare aquatic creatures. These creatures don’t rely on sunlight to survive in the deep ocean, unlike other sea animals who depend on the sun for light and energy.
Though we might not be able to see it above ground, much is happening below the ocean surface. Underwater activity is an important and mysterious part of life on planet Earth.
[Source: Volcanoes and Earthquakes]