The ocean is called a large expanse of salt water that separates two or more terrestrial continents.
These aquatic extensions cover most of the surface of our planet (71% of it) and communicate with each other, over miles of square kilometers and contain more than one trillion cubic kilometers of water.
Given these dimensions, it is understandable that the oceans are a distinctive feature of our world. They originated life and still maintain the highest percentage of biodiversity, which also means that it is the source of food for man and many other economic and recreational activities.
Therefore, throughout the history of the human being, the oceans have fascinated and particularly frightened him, which is a window of opportunities as well as a dividing border, which prevents him from moving through his own means of a corner of the earth to another
In addition, given that it extends to water bodies, it plays a vital role in the natural cycles of the planet, numerous climatic accidents and natural disasters are faced on its surface, often putting human coastal populations at risk.
Characteristics Of Oceans
The oceans are true colossal masses of water. Its estimated area is 361,000,000 km2, which means three quarters of the entire planet.
They have an average depth of 3900 meters (with known exceptions of much more, such as the Marianas trench of 11,034 meters), which represents about 1,300,000,000 km3 of volume, that is, 94% of the planet’s water.
There are three major oceans in the world: the Pacific, the Atlantic and the Indian, followed by two smaller oceans: the Arctic and the Antarctic. The first two of the list are usually divided, in addition, in Pacific and North Atlantic or South, respectively. Of all of them, the largest is the Pacific.
The Atlantic separates the continents of Europe and Africa from the American continent, while the Pacific separates the latter from Asia and Oceania. The Indian Ocean, on the other hand, separates the African continent from Asia and from Oceania, below India.
The Arctic and Antarctic oceans are in the vicinity of their respective north and south poles.
While water seems to be a substance universally present in our world, we are not very sure about its origin on our planet, given its absence in the others we know.
It is estimated that when the Earth cooled enough to allow the appearance of liquid water, it would generate a reduced amount that would later be increased by the ice arriving from outer space in the form of comets from the asteroid belt of our solar system.
The water of the oceans is salty, since it contains enormous quantities of sodium and chlorine in solid form, which turns into common salt (sodium chloride). Salinity levels are variable, however, and in the polar regions it is rather scarce.
Oceanic water also contains magnesium, potassium, calcium and other elements in a much smaller proportion. It is estimated that, given its dimensions, all the known elements can be found in it.
A curious fact about the water of the oceans is that its blue color, contrary to what one thinks, is not due exclusively to the reflection of the blue of the skies, but because it is in considerable proportions, the water tends to be bluish.
The water of the oceans has a variable temperature, which usually oscillates between 12 and 30 ° C in its surface temperate layer, which can go from the surface to 50 or even 100 meters deep.
Below these distances, the liquid remains between 5 and -1 ° C. Obviously these values are higher in the tropical waters and close to the equator, and lower as we approach the poles. Similarly, ocean water is warmer in summer and colder in winter.
The water of the oceans is never quiet, but is in constant movement due to the different types of existing tides, caused by the gravitational force of the Moon and the Sun. In this way, the face of the planet exposed to the moon will exhibit an apparent increase in the volume of the waters, while that exposed to the sun an apparent decrease.
This gives rise to two types of tide:
Spring tides. They occur when the moon is in the New or Full phase, that is, when the Earth, the Moon and the Sun are on the same line, and the gravitational force of both stars combines, achieving maximum attraction over the water mass.
Dead Tides They occur when the Moon and the Sun are at opposite ends of the planet, thus canceling their attraction to each other in opposite directions. They occur in the waning or increasing phases of the Moon.
8. Ocean currents
Another form of movement of the oceanic waters are the marine currents, product of the action of the wind on the water, that displaces them and puts in movement, next to the effect Coriolis and the terrestrial rotation. There are 28 different ocean currents known, each one connecting different sectors of the planet in a sort of tangle:
The water of the oceans can be the source of many natural disasters, both because of its effect on the planetary climate, because inside the oceans the temperature varies and leads to changes in pressure and generation of air masses in motion. This may well lead to storms, hurricanes, tornadoes or other climatic disasters that particularly affect coastal populations.
Similarly, earthquakes and tidal waves can alter the regular behavior of the waters and trigger tsunamis, which are gigantic waves that flood everything in their path.
The environmental impact of human industrial activity on the ecosystem does not exempt the ocean from suffering its effects. Which is an environmental tragedy if we consider that 70% of the planet’s oxygen comes from the plankton on the ocean surface, which means that the oceans absorb huge amounts of carbon dioxide and prevent the greenhouse effect.
However, it is estimated that life in the oceans has decreased by 40% since 1950, due to over-exploitation of fisheries but also to pollution, as many industrial complexes dump their toxic waste into the sea.
It has been said that the ecological destruction of the oceans is already done by 20-30%, and the most alarmist voices announce a possible mass extinction of ocean life for 25 years, to follow everything as it goes.