A seamount is an underwater mountain formed by volcanic activity. ... Thanks to the steep slopes of seamounts, nutrients are carried upwards from the depths of the oceans toward the sunlit surface, providing food for creatures ranging from corals to fish to crustaceans.

What is a seamount also called?

After they have subsided and sunk below the sea surface such flat-top seamounts are called "guyots" or "tablemounts".

Why are undersea mountains flat?

When an undersea volcano grows high enough to be near or breach the ocean surface, wave action and/or coral reef growth tend to create a flat-topped edifice. ... In addition, the erosive effects of waves and currents are found mostly near the surface: the tops of guyots generally lie below this higher-erosion zone.