World Ocean Day
With an average depth of 12,450ft, oceans cover 71% of the Earth’s surface. They play a crucial role in regulating our climate and atmosphere. In fact, without water, life itself would be itself impossible. Let’s take a journey through water kingdom.
The origin: The oceans originated at the time of the Earth’s formation close to 4.6 billion years ago. According to historians and researchers, at that time the Earth was almost entirely covered in water with just a few small islands. Roughly around 200 million years ago, the Earth’s surface was very different from how it is today. All the landmasses were grouped together into one vast supercontinent called Pangaea, while the rest of the globe was covered by a single great ocean known as Panthalassa, also known as the Panthalassic Ocean. Panthalassa comprised of the Pacific Ocean to the west and north and the Tethys Ocean to the southeast of Pangaea.
Over millions of years, the supercontinent began to slowly split apart, which eventually led to the formation of the modern continents and the Atlantic and Indian Oceans. And finally, 35 million years ago, the water and the land split to form the pattern we are now familiar with.
Currently, there are five major oceans - the Pacific Ocean, Atlantic Ocean, Indian Ocean, Southern or Antarctic Ocean and Arctic Ocean. While the Pacific is the deepest and largest (almost as large as all the others combined), the Atlantic and the Indian Oceans are similar in average depth. The Arctic is the smallest and shallowest. These oceans, although distinct in some ways, are all interconnected, as the same water circulates through them through different currents.
However, according to researchers, the continents still drifting apart. While the Pacific Ocean is slowly shrinking, the Atlantic and Indian Oceans are spreading wider by a few inches every year. In fact, the Red Sea at the northeast corner of Africa is widening so much that in the next 200 million years, it will be as wide as the Atlantic Ocean today.
Plants in the Oceans: Oceans are home to billions of plants and animals. There are two types of plants found in the ocean - those that have roots and are attached to the ocean floor and those that do not have roots and simply drift about in water. The rooted plants are only found in shallow water.
The most abundant plants found in the ocean are the phytoplankton. These are usually single-celled, minute, floating plants that drift across the surface of the oceans. Phytoplankton produce about 50% of our oxygen supply. They are so productive that each year, nearly 200 million tonnes of phytoplankton grow in the world’s oceans.
Animals in the oceans: Although 94% of life on Earth is aquatic, two-thirds of marine life has still remained unidentified. Marine animals are divided into three groups - zooplankton, nekton and benthos.
Zooplankton are drifting animals and usually small in size. The zooplankton population also includes some temporary members such as fish eggs or larval forms of organisms, which may grow up and leave the community to join the nekton or benthos. Nekton are the free swimmers and probably the largest portion of animals found in the ocean. Commonly found fishes, octopuses, whales, eels and squids are all examples of nekton. The third type of sea animal spends its entire life on the ocean floor. This includes lobsters, starfish, various worms, snails and oysters, among many more. Some of these creatures, such as lobsters and snails, may be able to move about on the bottom but their lifestyle is bound to the ocean floor and they cannot survive away from this environment.
Did you know?
● The oceans contain 1.34 billion cubic kms of water.
● 97% of the water on Earth is seawater and less than 1% is freshwater, while the remaining 2% is contained in glaciers and ice caps.
● Mid-Ocean Ridge, which is the Earth’s longest mountain range, is located underwater. It is longer than the Andes, Rockies and Himalayas combined.
● More than 90% of all volcanic activity occurs in the oceans.
● The average seawater temperature is 3.5 degree Celsius.
● Oil is the largest pollutant of the ocean; 5 million tonnes of oil enter the oceans each year.
● The largest known waterfall on earth lies underwater, between Greenland and Iceland.
