Education

# How Deep is the Ocean? Where is the Deepest Part of the Ocean?

About 71% of the planet Earth is made up of water. 96.5% of the total water found on Earth is in the form of oceans. Mount Everest is the highest point in the world, you know. But do you know what the deepest place in the world is and where it is found? In this piece of construct, we will learn: how deep is the ocean? Where is the deepest part of the ocean? How deep is the ocean at its deepest point? How deep is the Mariana Trench? Let’s get started!

## Difference between Ocean and Sea

Apparently, there is not much difference between ocean and sea. However, there is a slight geographical difference between them.

Ocean is larger than the sea. Let’s just say that the sea is actually a small part of the ocean. The ocean is open on all sides, meaning you see water everywhere. If there is land on either side of it, that is, if the water of the ocean touches the ground, then that part is called sea.

The Indian Ocean, for example, when it meets land, we call it Arabian Sea towards Pakistan, India and Oman, while towards Yemen, Saudi Arabia and Ethiopia etc. we call it Red Sea, that is, both the Red Sea and the Arabian Sea are part of the Indian Ocean.

Similarly, if the ocean water makes its way somewhere on land and water is surrounded by land on three sides, it is called bay. For example, both the Bay of Bengal and the Persian Gulf originate from the Indian Ocean. If you want to have a detailed and crystal clear distinction and description of the difference between sea and ocean, here is the way to go.

## How is the Ocean Depth Measured?

In the old days the methods of measuring the depth of the ocean were different from today. The weight was usually tied to a long rope and thrown into the ocean. And later, the length of wet rope would be measured. Nowadays, two methods to answer the question “how deep is the ocean” are considered to be the most important.

One is sonar technology – a depth measurement instrument, depth is measured using sounds. Sound waves from a device are formed, they collide with ocean bottom and return to the surface as an echo. This time is noted and then the depth is measured.

The second method is the use of radar and satellite. Radar sends electromagnetic waves into the ocean that hit the bottom and come back. However, these waves travel faster in the air than in water. Therefore, through a device, the travel time of these radio waves from ocean surface level to a satellite is noted. And later, with the help of all this data, the depth of the ocean is extracted. This method is more difficult and time consuming than sonar.

## How Deep is the Ocean?

It was generally believed that as we go deeper, the life will disappear. One and a half hundred years ago today, a voyage from England began in 1872 to prove this idea wrong. A warship was selected for the voyage, which was transformed into a lab. 250 people were on board, including six scientists. These people traveled in different oceans and measured the depth of the oceans from different places with the help of rope and weight. They also discovered many marine species on this trip.

In 1875, this group traveled from all over the world to a place in the Pacific Ocean fifteen hundred miles east of the Philippines. When the rope was thrown into the water to measure the depth of this point, the rope went insufficient. In this place, the tectonic plates of the earth beneath the ocean floor have thrust under each other, which is why it forms a ditch in the ocean. That is why this special point is named The Mariana Trench.

## How Deep is the Mariana Trench?

The depth of this trench is 36,200 feet or eleven kilometers. The last point of this trench is named Challenger deep – deepest part of the ocean. And this is considered to be the deepest point on our planet.

The depth is of Mariana Trench is greater than the height of Mount Everest. The depth of the Mariana Trench is 36,200 feet, while the height of Mount Everest is about 29,000 feet. The average depth of ocean is 12,140 feet. The Pacific Ocean is the largest and deepest ocean in the world. The length is 14,500 kilometers. The Mariana Trench is also located in it. The closest island to the Mariana Trench is the island of Guam. This island is under control of the United States. The United States also has management authority over the Mariana Trench.

## Has Anyone Descended to Challenger Deep?

First, in 1960, two oceanographers arrived at Challenger Deep in a submarine. One was from Switzerland and the other was an American. While learning ‘how deep is the ocean?’ you must be aware of the fact that so far more than twenty people have reached Challenger Deep.

## Zones of Ocean Depth

The first zone is up to 200 meters below sea level from surface. There is a lot of sunlight in this area. Therefore, there are plants that are undergoing photosynthesis. Ocean surface temperatures are usually minus two to thirty-two degrees Celsius. As we go deeper into the ocean, the water pressure starts to rise.

The second zone of the ocean starts from a depth of 200 meters. In this section, light reaches less than the first part. Photosynthesis plants are rare in this zone, but fish and other living things are more common. The sea temperature also starts falling in this part.

The third zone starts from one thousand meters. And sunlight does not reach it at all. There are many kinds of aquatic species here. These include jellyfish etc. After 4,000 meters, the fourth zone of the ocean begins. The water in this part is very cold. It is completely dark here and the water pressure is very high. Underwater volcanoes are also found in this zone. Sea creatures, however, are rarely found here.

The last fifth zone or the deepest zone starts after 6,000 meters. The Mariana Trench is found in this part. Pressure increases exponentially here. That is why very few people are able to reach such depths.

Oceans provide us with oxygen. They also absorb carbon dioxide. They cause climate change. Clouds also cause rain to fall. Marine life is also used to make various medicines. And the oceans are also used for transport. Ocean water is not fit for human consumption as it contains a lot of salts. However, it may be used after treatment. Hope, while dealing with the question ‘how deep is the ocean?’ you’d have grasped other interconnected concepts and facts.

Let’s dive into how deep is the ocean with reference to the different units of length: