56 Land Under Water-High

Land Under Water FOCUS Question What does the land look like under the ocean?

A Hidden Landscape Imagine you are on a boat on the ocean. You look down into the water. The ocean is so deep, it looks as if it goes on forever. But all that water sits on top of land. This land has many shapes. It has flat areas, high places, and low spots. It's just like the land above water! Word Wise "The ocean" can mean one ocean or all five oceans on Earth. They're all connected as one body of water!

Continental Shelf A continent is a big piece of land. Most of this land is above water. But some of it, around the edges, is below the water. Have you been to the beach? When you walk into the water, you are stepping onto the continental shelf! The water is not very deep here. Sunlight reaches the ocean floor and warms the water.

Continental Slope At first the continental shelf slopes down gently. Then the seafloor becomes steep. This steep part is the continental slope. The seafloor is now very deep. It is far below sea level. The water is cold and dark. Sunlight cannot reach this deep.

Deep-Ocean Floor At the bottom of the continental slope is the deep-ocean floor. Tiny pieces of sand and rock sink down and land on the continental slope. Then the sand and rock slide down the slope. They pile up on the deep-ocean floor. Over time, a thick layer of sand and rock builds up. Do You Know? An abyss is a very deep place. Most of the deep-ocean floor is called the abyssal plain.

Highs and Lows The deep-ocean floor is not always flat. There are mountains and valleys below water just like there are above water. Seamounts are mountains under the ocean. Most seamounts are too short to reach the surface. If the top of a seamount is above water, that part is called an island.