Which ocean is also known as the Southern Ocean?

Oceans

Oceans occupy about 70 per cent of the Earth’s surface. There are five oceans in the world. They are the Atlantic, Pacific, Indian, Arctic and Antarctic oceans. The surface under the oceans is called the ocean floor. Like land, the ocean floor also has natural features like plains, valleys and mountains.

Which ocean is also known as the Southern Ocean?

A The Antarctic Ocean is also called the Southern Ocean. Until recently, the Antarctic
Ocean was considered to be a part of the other main oceans, as it was actually formed
from parts of the Pacific, Atlantic and Indian oceans. In the year 2000, however, it was
officially named the ‘Southern Ocean’.

What is the ocean floor like?

A The ocean floor is far from flat. The edges of islands and continents gently slope
into the surrounding water to form an area called a continental shelf that is higher than
rest of the ocean floor. A continental shelf usually extends about 75 kilometres (47 miles)
out to sea but some, like the Siberian shelf in the Arctic Ocean, can extend up to 1,500
kilometres (932 miles). The continental shelf contains large deposits of petroleum, natural
gas and minerals. It also receives the most sunlight, so marine life thrives here. The
point where the continental shelf starts to plunge steeply towards the deep ocean floor
is called the continental slope. It is here that the deep canyons of the ocean are found.

What causes the formation of mountains and valleys on the ocean floor?

A Like the rest of the Earth, the ocean floor is divided into tectonic plates. The
movement of these plates is responsible for features like ridges, trenches, and valleys.
Ridges are formed when two plates drift apart. Boiling rock from inside the Earth,
called magma, oozes out through the cracks between the plates and cools to form a ridge.
Trenches are formed when a heavier plate sinks down under a lighter one.

Ocean currents
The water in the oceans and seas is always in motion,
due to the rotation of the Earth, the gravitational pull
of the Sun and Moon, and the difference in temperature
and salt content of the water. These movements form
strong currents in the oceans, both at the surface
and deep down.

Not a flat floor
The ocean floor has mountains and valleys. Some of the
mountains are tall enough to rise above the surface and
form islands.

1. Which is the largest of all oceans?
The Pacific Ocean is the world’s largest and deepest ocean. It has
an average depth of over 4,000 metres (13,100 feet). It has the world’s deepest trench
– the Mariana Trench near Japan. The Challenger Deep in the Mariana Trench is the
deepest point on Earth – about 11,033 metres (36,200 feet) deep.

2. What causes ocean current?
An ocean current is a mass of water that keeps moving in one direction. Surface
currents are caused by wind and the Earth’s rotation. Underwater currents are the result
of differences in temperature and salt content of the water.

3. What is a black smoker?
When water seeps into the crust of the ocean floor through cracks, it
may be heated by the magma below. As pressure builds up within the crust, the
hot water shoots up through these cracks. These jets of warm water are often black
due to their mineral content, so they are called black smokers.