Hydrosphere : An Introduction With Important Terms

Hydrosphere : An Introduction

As we all know that one-third (about 30%) of the total area of the earth is present in the form of land and about two-thirds (about 70%) is present in the form of water area. Most of this water area is covered by oceans and seas.

Genetic Terminology - Genetics

There are four Oceans on the earth –

1. Pacific Ocean - Total area about 165.2 million sq km

2 . Atlantic Ocean – Total area about 106.4 million sq.km.

3. Indian Ocean - Total area about 73.6 million sq km

4. Antarctic Ocean - Total area about 18.8 million sq km

SONAR – Sound Navigation And Ranging

SONAR is a technique, in which with the help of sound waves, the objects present inside water or ocean or the depths of mountain and ocean are detected. SONAR is a special tool for navigation in Oceans.

Hypsographic Curve

More diversity is found in the ocean floor than in the land part of the earth. The graph or curve by which the height of the land and the depth of the sea are jointly displayed is called the Hypsographic Curve.

Topographies Formed By Ocean Water

On the basis of high altitude graph, mainly four major reliefs are found in the ocean floor, which are as follows –

1. Continental Shelf

2. Continental Slope

3. Deep Sea Plains

4. Submarine Deep & Trenchs

1. Continental Shelf

The shallow part adjacent to the ocean coast is called the Continental Shelf. Its average width is about 70 km and depth is about 150 – 200 m or 100 fathoms (1 fathom = 6 feet). The slope of this region ranges from 1 degree to 3 degree. It consists mainly of terrestrial deposits.

The shallow parts of the continental shelf are considered to be the main areas of fishing. Along with this, one-fourth of the world's petroleum and natural gas are found in these areas.

2 . Continental Slope

The part of the sharp slope present between the submerged coast and the deep ocean floor is called Continental Slope. The slope also varies in different parts. Its depth ranges from 200 – 2000 m. The gradient in this region ranges from about 2° – 5°

3. Deep Sea Plains

The widest part of the ocean floor is the deep sea plain. Their depth can be up to 3000 – 6000 meters. These sea plains are hundreds of kilometers wide and thousands of kilometers long.

4. Submarine Deep & Trenchs

These are the deepest parts of the oceanic submergence zone. Their shields stand up. They are found on about 7% of the total ocean floor area. Their position is mainly seen in front of mountains and with the help of islands.

Major ocean trenches are Sunda Trench – 8152 m (in Indian Ocean near Java Island), Mariana Trench – 11022 m (in Philippines), Atacama Trench, Curile Trench, Tonga Trench – 9000 m, Mindanao Trench – 10500 m etc. 

Drainage System and Drainage Pattern

Oceanic Ridges

Mountain ranges are found at the bottom of the ocean, whose width is around 100 km and length is around 1000 km. They form the longest mountain range found on earth. Some examples of which are as follows –

• Mid-Atlantic Ridge - It extends from Iceland in the north to Bovet Island in the south in the shape of 'S', whose length is about 14400 km.
• Intermediate main ridge Indian Ocean – It starts from the submerging coast of peninsular India in the north of the Indian Ocean (where its width is 320 km. In this part it is called Laccadive Chagos.) It expands towards the south, and the equator and Near 30 degree latitude (in this part it is called Chagos Centerpal ) . they have come above the ridge sea. Due to which many islands have been formed. These islands are called Laccadive, Maldives, Chagos, New Amsterdam, St. Paul respectively.
• Ninty East Ridge – It is situated in the Indian Ocean. Its extension is spread parallel to 90 degree east longitude. Its length is approximately 5000 km. Its width is about 200 km, which extends from 33 degree southern latitude to 17 degree northern latitude.

Sea Mountains and Guiants

Such submerged mountains whose summits are more than 1000 m above sea level are called sea mountains. And the mountains with flat top are called Guyant.

Canyon

Deep gorges on the ocean floor are called submerged gorges called canyons. The longest canyon in the world is found in the Bering Sea west of Alaska. Their depth can be from 1000 m to 3000 m.

Datum Line

The horizontal line of the sea level with the help of which heights and depths are measured, is called Datum line.

Hybridization Experiment of Gregor John Mendel and Mendel

Major Oceans on Earth

1. The Mediterranean Sea is the largest sea surrounded by land. Its depth is approximately 4632 m and it is spread over Europe, Anatolia and East Africa.
2. Black Sea – It is a continental sea, whose expansion is Georgia in the east, Bulgaria and Romania in the west, Russia and Ukraine in the north-east, Europe in the south-east, the peninsula of Caucasus and Anatolia (Turkey) and Turkey in the south.
3. South China Sea – It is a part of the Pacific Ocean located south of China, which extends to China, Taiwan, Philippines, Vietnam, Indonesia, Brunei, Malaysia.
4. Caspian Sea – It is the largest salt water lake in the world. It is bordered by Russia, Azerbaijan, Iran, Turkmenistan and Kazakhstan.
5. Bering Sea – It is located between the northeastern region of Asia and Alaska of North America. Russia and America are its coastal areas.
6. Sea of Japan – It is a part of the western Pacific Ocean, which is connected to the islands of Japan, the islands of Russia and the mainland of Asia.
7. Arabian Sea – It is attached to the south-west of India.
8. Andaman Sea – It is located in the south-east of the Bay of Bengal, south of Myanmar and west of Thailand. It is about 1200 km long from north to south and 650 km wide from east to west.
9. Caribbean Sea - Mexico is located in its west and Central America in the southwest. The islands of the Greater Antilles are in the north and the islands of the Lesser Antilles in the east.

Carbon Footprint : Impact and Prevention