Where is the continental shelf?

The continental shelves of our planet surround the land masses and large islands. They are like doorsteps sloping down from the dry land to the watery depths of the oceans. The tides wash up and down in these areas and the shallow sunlit waters teem with sea life comparable to the thriving plants and animals that inhabit the lush meadows of the dry land.

When you bathe from your favorite beach, you soon learn that the sand floor dips down to deeper and deeper water as you leave the shore. This gentle slope is the continental shelf, the doorstep between the dry land and the ocean abyss. North of Cape Hatteras, the shelf is 150 miles wide. Off the Pacific coast, it is about 20 miles wide. Around the world, the width of the continental shelves varies from lefts than a mile to 200 miles.

The wide shelves dip more gradually than the narrow shelves and most of them end abruptly when the water is about ?2 fathoms deep. At this depth, the red and gold rays of sunlight have been filtered out and the water is a dark and vivid blue. Here we reach some of the most dramatic geological formations on the face of our globe.

In many cases, the edges of the continental shelves plunge two to five miles down sheer cliffs, or escarpments. These cliffs are the walls of the true ocean basins, the floors of which rest anywhere from three to six miles below the surface of the sea. There is nothing on the dry land to compare with these towering cliffs and we know about them only by the use of sonar and various instruments used in probing the ocean depths.

Throughout the ages, the earth’s sea and land areas have waged  areas have waged restless warfare, Time after time the seas have invaded the land and receded  each battle taking tens of millions of years. The home territory of the seas is the deep ocean basins. The continental shelves, geologically speaking, belong to the continents.

But the sloping doorsteps have been the watery no manes land in the age long conflict between land and sea. Right now, the water is winning a battle and the worlds sea level is slowly rising.

The shallow waters above the continental shelves are bright with sunlight and vigorous with oxygen dissolved from the air in the tossing waves. Microscopic alga and floating seaweeds thrive in these waters and teeming animals feed on the plant life in the watery meadows and on each other,