Ocean floor is the land surface under an ocean and it  includes the topography in it. The ocean floor can be categorized into four different parts viz. deep sea plains, continental shelf, oceanic deeps, and continental slopes. Apart from these categories, divisions in the form of trenches, guyots, canyons, sea mounts, ridges, etc. also exist. 

Major Divisions

Continental Shelf

When gulfs and seas that are relatively shallow occupy a continent’s extended boundary or margin, it is known as the continental shelf. 

• Continental Shelf is a shallow region that shows a gradient of 1-degree or even less at certain places
• This part usually ends at a steep slope which is referred to as the shelf break
• Continental shelf is irregularly wide in different oceans. Its width is around 80 kilometers on an average
• These shelves do not appear or are quite narrow along some coastal margins like that of Sumantra’s west coast, Chile, etc. The Arctic Ocean’s Siberian Shelf is up to 1,500 kilometers wide making it the largest shelf in the world
• Shelf depth varies from place to place. In some areas it might be as shallow as 30 meters whereas in some regions it can be as deep as 600 meters
• The thickness of sediments that appear on the shelves vary. These sediments are carried by wind, glaciers, rivers, etc. from the surface and are spread by ocean currents and waves

Continental Slope

• The part of the ocean floor that links the ocean basin with the shelf is called the continental slope
• It starts at the lowest part of the continental shelf where it breaks down into a steep slope
• The slope region exhibits a gradient between 2 to 5-degrees
• The slope can be 200 to 3000 meters deep
• The end of the continents is indicated by the slope boundary
• Trenches and canyons can be found in the continental slope

Deep Sea Plains

• The ocean basins have gentle sloping regions. These regions are known as deep sea plains
• Their depth varies from 3000 to 6000 meters
• Sediments composed of fine gradients such as silt and clay cover these plains

Deeps and Trenches

• The deepest areas of the ocean floor are known as deeps or trenches
• The steep-sided part with narrow basins is called the trench. They are around 3 to 5 kilometers deeper than the ocean floor that surrounds them
• They are found at the bottom of the continental slopes and alongside arcs of the islands. They are linked with the powerful earthquakes and active volcanoes. As a result, studying them is essential for examining plate movement
• Around 57 oceanic deeps have been found so far. Out of that 6, 19, and 32 deeps are found in the Indian, Atlantic, and Pacific Oceans respectively

Minor Relief Features 

Different areas of the oceans contain minor but essential features that are known as minor relief features. 

Mid-Oceanic Ridges 

• When 2 mountain chains are divided by a huge depression, it is called a mid-oceanic ridge
• The peaks of these mountain ranges can be higher up to 2500 meters and some of them even appear above the surface of the ocean. For instance, Iceland is a portion of the mid-Atlantic Ridge

Seamount 

• The mountain rising from the seafood that does not extend up to the surface of the ocean and consists of pointed summits is called a seamount
• These are volcanic mountains
• Some of them are up to 3000 to 4000 meters high. For instance, the Emperor Seamount that lies in the Pacific Ocean is said to be the extended part of the Hawaiian Islands

Submarine Canyons

• The valleys that are deep enough to be compared with the Colorado River’s Grand Canyon are called submarine canyons
• They sometimes cut through the continental slopes and shelves and often originate from the river mouths
• One of the most popular submarine canyons across the globe is the Hudson Canyon

Guyots 

• When the seamount has a flat top, it is known as a guyot
• The subsidence that happens gradually with time is evident from their flat tops
• The Pacific Ocean is said to have over 10,000 guyots and seamounts

Atoll 

• When coral reefs surround a central depression, these low islands are known as Atoll. These are typically found in the tropical oceans
• It can be a portion of the sea (lagoon) and at times form the borders of a fresh, saline, or brackish water body

Temperature of Ocean Water

• Ocean water also gets heated up as land, but the process is slower in the oceanic water in comparison to land

Conclusion

Ocean floor is categorized into four major categories, i.e. deep sea plains, continental shelf, oceanic deeps, and continental slopes and several minor relief features. All of these have varied features and are home to various fishes and under ocean creatures.