Seamount chains are underwater mountains formed by volcanic activity. These mountains rise from the ocean floor but do not reach the surface of the water. They often occur in long, linear arrangements, created as tectonic plates move over stationary hotspots in the Earth's mantle. As the tectonic plate shifts, new volcanoes can form, while older ones become inactive and erode over time. This process results in a series of seamounts that can stretch for hundreds or even thousands of kilometers. Seamount chains are important for marine ecosystems, providing habitats for various species and influencing ocean currents.