Oceans cover nearly 68% of earth’s surface! Because of its vast expanse the oceans contain an enormous amount of life from tiny phytoplankton and zooplankton to giant whales. The ocean is filled with countless species of plant and animal life that span from coral reefs to the open ocean to the deepest darkest depths of the ocean. The diversity of life in oceans is vast, and scientists believe there are many organisms that have not even been discovered yet!
When a continent meets the ocean it will gently start sloping down to the ocean floor. This gentle slope is called the continental shelf. As you get farther from the continent the slope becomes steeper. The steeper part of the slope is called the continental slope and this slopes down to reach the sea floor deep below the ocean’s surface.
The ocean can be broken into 4 main zones depending on depth and amount of sunlight that can penetrate to the zone. These zones are the intertidal zone, the pelagic zone, the aphotic zone and the benthic zone. Different organisms can be found living in different zones. Some organisms like coral can be found in zones closer to the water's surface while other organisms like the angler fish can only be found in deeper zones of the ocean.
Ocean tides are the rise and fall of the sea level each day caused by the moon’s gravitation pull. Each day there is a high tide and a low tide.
Source: Prentice Hall Science Explorer, Life Science. Pearson Education 2009.