The Bottom Relief of the Ocean describes the whole shape of the seafloor with its height above sea level and depth with the shape of its bottom relief. The bottom relief of a sea includes the different sizes of mountains, hills, so many ridges, plains, and different valleys. These oceanic features have some differences from the continental features as they belong to the Oceanic crust. The Oceanic crust is 60-70 million years old. The oceans cover 69% of the total earth’s surface. On the other hand, the continents cover 29% of the whole earth’s surface.
In this article, we are going to discuss the Bottom Relief of the Ocean in detail.
Bottom Relief of Ocean| Class 11 Geography
Bottom Relief of the Ocean
The Bottom Relief of the Ocean displays the variation in the process of elevation of the Seafloor. This can happen due to various factors like different tectonic activities, sedimentation, and erosion.
General Characteristics of Bottom Relief of the Ocean
The Bottom Relief of the Ocean affects the wave actions and its circulation. It also contributes to the proper distribution of the marine life. Here are some general characteristics of Bottom Relief of the Ocean as mentioned below.
- Bottom Relief of the Ocean is like land that is present under of the ocean. We can consider it as an underwater landscape.
- Underwater landscape has mountains, basins, plateaus, ridges, canyons, and trenches.
- Submarine relief means ocean floor features.
- Before SONAR, people thought ocean floor was flat.
- Technology like SONAR makes it easier to explore Bottom Relief of the Ocean with its structure and features.
Basic Configuration of Bottom Relief of the Ocean
Based on the depth and different relief patterns, the Bottom Relief of the Ocean can be divided into four major divisions. It includes Continental Shelf, Continental Slope, Abyssal Plains and Submarine Trenches. Let us discuss in detail.
| Aspects | Continental Shelf | Continental Slope | Continental Rise | Abyssal Plains |
|---|---|---|---|---|
| Definition | Shallow submerged extension of a continent. | Sloping segment from the land edge to the deep ocean floor. | Transition zone connecting slope to deep sea. | Flat, featureless expanses on the deep-sea floor. |
| Depth | Typically ranges from 120 to 370 meters deep. | Depths vary from 180 to 3600 meters below sea level. | Gradual decrease in depth towards the deep ocean floor. | Extends from 3000 to 6000 meters below sea level. |
| Width | Varies significantly, from a few kilometers to over 100 kilometers wide. | The average width of a continental slope is 25 miles. | The continental rise is a part of the continental margin. It can be as narrow as 15 miles and as wide as 228 miles. | The largest abyssal plain on Earth is the Sohm Plain. It is 900,000 square kilometers in size. |
| Sediment Deposits | Continental shelves hold significant sediment deposits. | Few sediments due to steepness and distance from land. | Belt of sediment deposits. | Covered with sediments, including organic matter. |
| Biodiversity | Rich in marine life due to shallow depths and sunlight. | Lower biodiversity compared to shelf due to depth and slope. | Lower biodiversity compared to shelf and rise. | Lower biodiversity compared to shallower regions. |
| Notable Features | Contains coral reefs and underwater valleys. | Characterized by steep slopes with few features. | Transitional zone where slope levels out. | Features undersea plateaus, hills, and mountains. |
| Sedimentary Formation | They are formed from different organic and inorganic materials carried by rivers, glaciers, and ice sheets. | Sediments accumulate at the bottom of the slope. | Accumulation of sediment between slope and deep ocean. | Formed by the buildup of sediments and organic material. |
Ocean Deeps or Submarine Trenches – Bottom Relief of Ocean
Ocean deeps and submarine trenches are deep parts of the sea. They are the shallow holes present in the ocean floor while trenches are deeper. They are long, narrow, and steep-sided, found near continental slopes and islands.
- Ocean deeps are the deepest parts of the ocean. It also known as Submarine trenches.
- Trenches may be close to continents and sometimes running alongside Fold Mountains.
- The Pacific Ocean hosts the most trenches with the Mariana Trench as the deepest spot.
- They generally found near the areas with active volcanoes and earthquakes prone areas.
- Ocean deeps are the origin of significant earthquakes and tsunamis.
Intresting Facts:
The deepest part of the Mariana Trench is called as the Challenger Deep. It is more than 7,000 feet deeper than the Mount Everest.
The Mariana Trench contains the largest single celled organisms yet discovered. It is called as Xenophyophores.
Bottom Reliefs of Ocean Features
The bottom relief of the ocean decides how it looks underwater of the ocean. This helps us learn about the past of that area, how ocean currents move, and what processes shape the ocean floor. Here are some features of the bottom relief of the ocean as mentioned below.
|
Bottom Reliefs of Ocean Features |
|
|---|---|
| Underwater mountain ranges | Ranges of mountains under the sea created by moving pieces of the Earth’s crust. |
| Seamounts | Isolated underwater mountains formed by volcanic activity. |
| Deep depressions | Deep, long indented areas in the ocean floor. |
| Guyots | Flat-topped underwater mountains worn away over time. |
| Volcanic mountains | Mountains created by volcanoes under the sea. |
| Reefs | Structures formed by sea creatures like coral. |
| Sandbanks | Shallow areas of the sea bottom covered in sand. |
| Atolls | Ring-shaped formations of coral reefs around sunken volcanic islands. |
Impacts of Bottom Relief of The Ocean
There are so many impacts of bottom relief of the ocean as mentioned below.
- The ocean floor affects how ocean currents move, which can impact the distribution of heat, nutrients, and sea life.
- In some places, deep, cold water rises to the surface, bringing nutrients that support marine life.
- The ocean floor shapes waves and water movements.
- It affects how sediment moves and coastlines change of the ocean.
- It plays a part in climate change.
- Different ocean floor features create homes for sea animals.
- Some plateaus have valuable minerals.
- It influences how ships navigate and where fishing occurs.
Major And Minor Bottom Relief of The Ocean
Here are the major differences between Major And Minor Bottom Relief of The Ocean as mentioned below.
| Aspects | Major Bottom Relief | Minor Bottom Relief |
|---|---|---|
| Description | Large-scale features shaping the ocean floor. | Smaller-scale features of the ocean floor. |
| Examples | Underwater mountain ranges, deep depressions, isolated underwater mountains. | Ridges, hills, seamounts, guyots, trenches, canyons, slopes, fracture zones, island arcs, atolls, coral reefs, submerged volcanoes, and sea scarps. |
| Size | Usually covering extensive areas. | Typically covering localized regions. |
| Impact on Ocean | Significantly affects ocean currents, climate, and habitats. | May influence local water movements, sediment distribution, and microenvironments. |
| Economic Importance | Often linked with valuable mineral deposits and major fishing areas. | Lesser economic significance, may offer local resources or recreational sites. |
Also Read
How Many Oceans are There in the World
Ocean Floor: Features, Types, and Structure
Ocean Currents – Meaning, Types, Causes, Effects
Coastal Landforms: Definition, Features & Formation
Coastal Erosion: Causes, Effects, Processes & Examples
FAQs – Class 11 Bottom Relief of Ocean
What are the minor relief features of the ocean floor Class 11?
Ridges, hills, seamounts, guyots, trenches, canyons, etc. are minor ocean reliefs. Mid-Oceanic Ridges: A mid-oceanic ridge is composed of two chains of mountains separated by a large depression. The mountain ranges can have peaks as high as 2,500 m and some even reach above the ocean’s surface.
What is the deepest relief in the ocean?
The Ocean Deeps or trenches are the deepest part of the ocean floor. They are relatively narrow and are the deepest parts of the world’s oceans. The Mariana Trench in the Pacific Ocean reaches the greatest known depth of about 36,000 feet.
What is in the bottom of the ocean?
Some features of the seabed include flat abyssal plains, mid-ocean ridges, deep trenches, and hydrothermal vents. Seabed topography is flat where layers of sediments cover the tectonic features. For example, the abyssal plain regions of the ocean are relatively flat and covered in many layers of sediments.
What are the ocean bottom relief features of Indian Ocean?
The bottom relief of the Indian Ocean resembles that of the Atlantic Ocean. This ocean has a continuous central ridge, called the Arabic-Indian Ridge, together with its southern extension, the Kerguelen-Gaussberg Ridge, which connects with the Antarctic continent.
What is relief of the ocean floor Class 11 geography?
Ocean relief refers to the physical features of the ocean floor. These features are formed due to various tectonic, volcanic, erosional, and depositional processes and their interactions. Ocean relief features can be broadly categorized into major and minor relief features.
What are the major and minor relief of the ocean?
Ocean relief can be divided into four major parts: The Continental Shelf, The Continental Slope, The Deep Sea Plain, and The Oceanic Deeps. Additionally, there are major and minor relief features in the ocean floors like ridges, hills, seamounts, guyots, trenches, canyons, etc.
Where is the bottom of the ocean?
The deepest part of the ocean is called the Challenger Deep and is located beneath the western Pacific Ocean in the southern end of the Mariana Trench, which runs several hundred kilometers southwest of the U.S. territorial island of Guam. Challenger Deep is approximately 10,935 meters (35,876 feet) deep.