About 94 per cent of the Earth’s living beings exist inside the oceans. It is no surprise that most of the Earth’s surface is covered by water.
According to the National Ocean Service of the United States, we have explored less than five per cent of oceans on Earth, while the rest remains unexplored.
As per the World Register of Marine Species, there are 240,470 marine species known. However, it is only a small part of all the species that exist in the ocean, and new ones are being discovered every day.
There are lakes and rivers inside the ocean. This can happen when hydrogen sulfide combines with salt water and it becomes more dense than surrounding water.
The longest mountain range in the world, Mid-Ocean Ridge, is underwater. It spans about 65,000 kilometres beneath the ocean.
It is believed that about 70 to 80 per cent of the Earth’s oxygen is generated by marine plants, most of which are marine algae.