Bathymetry is the study of the depth and floors of bodies of water. This field describes the major bathymetric features found on the ocean floor. Specific bathymetric features associated with each of the following categories are listed for each ocean.

The continental shelf is a rather flat area of the sea floor adjacent to the coast that gradually slopes down from the shore to water depths of about 200 m (660 ft). It is narrow or nearly nonexistent in some places; in others, it extends for hundreds of miles.

The continental slope is where the bottom drops off more rapidly until it meets the deep-sea floor (abyssal plain) at about 3,200 m (10,500 ft) water depth. The continental slope can be indented by submarine canyons, often associated with the outflow of major rivers. Another feature of the continental slope are alluvial fans or cones of sediments carried downstream to the ocean by major rivers and deposited down the slope.

The abyssal plains, at depths of over 3,000 m (10,000 ft) and covering 70% of the ocean floor, are the largest habitat on earth. Despite their name, these “plains” are not uniformly flat and are interrupted by features like hills, valleys, and seamounts.

The mid-ocean ridge, rising up from the abyssal plain, is a continuous range of undersea volcanic mountains that encircles the globe almost entirely underwater. It is the longest mountain range on Earth at over 64,000 km (40,000 mi) long, rising to an average depth of 2,400 m (8,000 ft). Mid-ocean ridges form at divergent plate boundaries where two tectonic plates are moving apart and magma creates new crust.

Seamounts are submarine mountains at least 1,000 m (3,300 ft) high, formed from individual volcanoes on the ocean floor. They are distinct from the plate-boundary volcanic system of the mid-ocean ridges, because seamounts tend to be circular or conical. Flat-topped seamounts are known as "guyots."

Ocean trenches are the deepest parts of the ocean floor and are created by the process of subduction, when tectonic plates move toward each other and one plate sinks (is subducted) under another.

Atolls are the remains of dormant volcanic islands. In warm tropical oceans, coral colonies establish themselves on the margins of the island. Over time, the high elevation of the island collapses and erodes away to sea level, leaving behind an outline of the island in the form of the coral reef. The resulting island typically has a low elevation of sand and coral with an interior shallow lagoon.

Arctic Ocean

continental shelf: more than one quarter of the Arctic sea floor; the Eurasian shelf is very wide, extending out 1,500 km (930 mi), and is the largest continental shelf in the world

the following are examples of continental-shelf features in the Arctic Ocean (see Figure 2):

Barents Shelf
Beaufort Shelf
Davis Sill
Chukchi Shelf
East Siberian Shelf
Kara Shelf
Laptev Shelf
Lincoln Shelf

continental slope: the following are examples of continental-slope features in the Arctic Ocean (see Figure 2):

Litke Trough
Novaya Zemlya Trough
Svyataya Anna Trough (Saint Anna Trough)
Voronin Trough

abyssal plains: the following are examples of abyssal-plain features in the Arctic Ocean (see Figure 2):

Baffin Basin
Canada Basin
Fram/Amundsen Basin
Greenland Abyssal Plain
Iceland Basin
Makarov Basin
Molloy Deep (deepest point in the Arctic Ocean)
Nansen Basin
Norwegian Basin

mid-ocean ridge: the following are examples of mid-ocean ridges in the Arctic Ocean (see Figure 2):

Gakkel Ridge
Mohns Ridge

undersea terrain features: the following are examples of undersea terrain features on the floor of the Arctic Ocean (see Figure 2):

Lomonosov Ridge
Gakkel Ridge
Alpha Ridge
Mendeleev Rise
Chukchi Plateau

ocean trenches: none

atolls: none

Atlantic Ocean

continental shelf: the passive margins of the Atlantic Ocean provide for wide continental shelves in North America, Northwest Europe, and the southern coast of South America

the following are examples of features on the continental shelf of the Atlantic Ocean:

Blake Plateau (Figure 5)
Celtic Shelf (Figure 2)
Dogger Bank (Figure 2)
Flemish Cap (Figure 2)
Falkland Plateau (Figure 3)
Grand Banks of Newfoundland (Figure 2)
Great Bahama Bank (Figure 5)
Little Bahama Bank (Figure 5)
Tunisian Plateau (Figure 4)
Yucatán Shelf (Figure 5)

continental slope: the following are examples of features on the continental slope of the Atlantic Ocean:

Amazon Cone (Figure 3)
Congo Fan (Figure 3)
Hudson Canyon (Figure 5)
Mississippi Fan (Figure 5)

abyssal plains: the following are examples of features on the abyssal plains of the Atlantic Ocean:

Angola Basin (Figure 3)
Agulhas Basin (Figure 3)
Argentine Basin (Figure 3)
Brazil Basin (Figure 3)
Canary Basin (Figure 2)
Cape Basin (Figure 3)
Colombia Basin (Figure 2)
Labrador Basin (Figure 2)
Mexico Basin (Figure 2)
Newfoundland Basin (Figure 2)
North American Basin (Figure 2)
Venezuela Basin (Figure 2)
West European Basin (Figure 2)

mid-ocean ridge: the Charlie-Gibbs Fracture Zone displaces the mid-ocean ridge 350 km to the west, separating the Mid-Atlantic Ridge from the Reykjanes Ridge; the Romanche Fracture Zone, located near the equator, offsets the Mid-Atlantic Ridge 900 km and is considered the dividing line between the North and South Atlantic Oceans

the following are examples of mid-ocean ridges on the floor of the Atlantic Ocean:

East Mediterranean Ridge (Figure 4)
Mid-Atlantic Ridge (Figures 2, 3)
Reykjanes Ridge (Figure 2)

undersea terrain features: the following are examples of undersea terrain features on the floor of the Atlantic Ocean:

Bermuda Rise (Figure 2)
Cape Verde Plateau (Figure 2)
New England Seamounts (Figure 2)
Rio Grande Plateau (Figure 3)
Rockall Plateau (Figure 2)

ocean trenches: the following are examples of ocean trenches on the floor of the Atlantic Ocean:

Cayman Trench (Caribbean Sea) (Figure 2)
Hellenic Trench (Mediterranean Sea) (Figure 4)
Puerto Rico Trench (Figure 2) - deepest point in the Atlantic
South Sandwich Trench (South Atlantic) (Figure 3)

atolls: Rocas Atoll (Brazil) is the only atoll in the South Atlantic
Indian Ocean
continental shelf: the following are examples of features on the continental shelf of the Indian Ocean (see Figure 2):

Exmouth Plateau
Indus Canyon
The Swatch of No Ground/Ganges Canyon (Bay of Bengal)
Sunda Shelf

continental slope: the following are examples of features on the continental slope of the Indian Ocean (see Figure 2):

Bengal Fan
Indus Fan

abyssal plains: the following are examples of features on the abyssal plains of the Indian Ocean (see Figure 2):

Arabian Basin
Crozet Basin
Madagascar Basin
Mid-Indian Basin
Mozambique Basin
Wharton Basin

mid-ocean ridge: the following are examples of mid-ocean ridges on the floor of the Indian Ocean (see Figure 2):

Central Indian Ridge
Davie Ridge
Southeast Indian Ridge
Southwest Indian Ridge

undersea terrain features: the following are examples of undersea terrain features on the floor of the Indian Ocean (see Figure 2):

Andaman-Nicobar Ridge
Chagos-Laccadive Ridge
Kerguelen Plateau
Madagascar Plateau
Mascarene Plateau
Mozambique Plateau
Ninetyeast Ridge

ocean trenches: the following are examples of ocean trenches on the floor of the Indian Ocean (see Figure 2):

Java/Sunda Trench (deepest point in the Indian Ocean)

atolls: the following are examples of atolls in the Indian Ocean (see Figure 2):

Bassas da India
Chagos Archipelago/Diego Garcia
Europa Island
Juan de Nova Island
Lakshadweep Islands
Maldive Islands
Seychelles

Pacific Ocean

continental shelf: the following are examples of features on the continental shelf of the Pacific Ocean:

Arafura Shelf (Figure 5)
Sahul Shelf (Figure 5)
Sunda Shelf (Figure 5)
Taiwan Banks (Figure 5)

continental slope: the following are examples of features on the continental slope of the Pacific Ocean:

Pribilof Canyon (Figure 2)
Zhemchug Canyon (Figure 2; deepest submarine canyon)

abyssal plains: the following are examples of features on the abyssal plains of the Pacific Ocean:

Aleutian Basin (Figure 2)
Central Pacific Basin (Figure 2)
Northeast Pacific Basin (Figure 2)
Northwest Pacific Basin (Figure 2)
Philippine Basin (Figure 4)
Southwest Pacific Basin (Figure 4)
Tasman Basin (Figure 4)

mid-ocean ridge: the following are examples of mid-ocean ridges on the floor of the Pacific Ocean:

East Pacific Rise (Figure 3)
Pacific-Antarctic Ridge (Figure 3)

undersea terrain features: the following are examples of undersea terrain features on the floor of the Pacific Ocean:

Caroline Seamounts (Figure 5)
East Mariana Ridge (Figure 4)
Emperor Seamount Chain (Figure 2)
Hawaiian Ridge (Figure 2)
Lord Howe Seamount Chain (Figure 4)
Louisville Ridge (Figure 4)
Kapingamarangi (Ontong-Java) Rise (Figure 5; largest submarine plateau)
Macclesfield Bank (Figure 5)
Marshall Seamounts (Figure 2)
Magellan Seamounts (Figure 2)
Mid-Pacific Seamounts (Figure 2)
Reed Tablemount (Figure 5)
Shatsky Rise (Figure 2; third-largest submarine plateau)
Tonga-Kermadec Ridge (Figure 4)

ocean trenches: the following are examples of ocean trenches on the floor of the Pacific Ocean:

Aleutian Trench (Figure 2)
Chile Trench (Figure 3)
Izu-Ogasawara Trench (Figure 2)
Japan Trench (Figure 2)
Kermadec Trench (Figures 3, 4)
Kuril-Kamchatka Trench (Figure 2)
Manus Trench (Figure 4)
Mariana Trench (Figures 2, 4; deepest ocean trench)
Middle America Trench (Figure 3)
Nansei-Shoto Trench (Figure 5)
Palau Trench (Figures 2, 4)
Philippine Trench (Figure 4)
Peru-Chile Trench (Figure 3)
South New Hebrides Trench (Figure 4)
Tonga Trench (Figures 3, 4)
Yap Trench (Figures 2, 4)

atolls: the following are examples of atolls in the Pacific Ocean, and because they are also countries or territories, they have entries in The World Factbook with additional information:

Federated States of Micronesia
French Polynesia
Kiribati
Marshall Islands
Midway Island
Tonga
Tuvalu
Vanuatu
Wake Island

Southern Ocean

continental shelf: the following are examples of features on the continental shelf of the Southern Ocean (see Figure 2):

Astrid Ridge (see also Figure 4)
Belgrano Bank
Gunnerus Ridge (see also Figure 4)
Hayes Bank
Iselin Bank

continental slope: the following are examples of features on the continental slope of the Southern Ocean (see Figure 2):

Amery Basin (Figure 4)
Filchner Trough
Hillary Canyon
Pobeda Canyon (Figure 3)

abyssal plains: the following are examples of features on the abyssal plains of the Southern Ocean (see Figures 2, 3, and 4):

Amundsen (Abyssal) Plain
Enderby (Abyssal) Plain
South Indian/Australian-Antarctic Basin
Southeast Pacific/Bellinghausen Basin
Weddell (Abyssal) Plain

mid-ocean ridge: the following are examples of mid-ocean ridges on the floor of the Southern Ocean (see Figure 2):

Pacific-Antarctic Ridge (Figure 3)

undersea terrain features: the following are examples of undersea terrain features on the floor of the Southern Ocean (see Figure 2):

Akopov Seamounts (Figure 3)
De Gerlache Seamounts (see also Figure 3, 4)
Endurance Ridge (Figure 4)
Marie Byrd Seamount (see also Figure 3)
Maud Rise (see also Figure 4)
Scott Seamounts (see also Figure 3)

ocean trenches: the following are examples of ocean trenches on the floor of the Southern Ocean (see Figure 2):

South Sandwich Trench (Figure 4; the deepest location in the Southern Ocean)

atolls: none, due to the extremely cold water