The etymology from tide takes us to the french word marée. The tide is the movement that sea waters make when descending and ascending alternately and periodically . This swing is a consequence of the attraction exercised by the moon and the sun .
Objects that have mass are attracted to each other by the natural phenomenon known as gravity . The moon and the sun, in this framework, exert forces of gravitational attraction on the planet land : the tide is the effect of these forces on the oceans.
Because of these forces , the tides develop and the sea level changes periodically. It is important to keep in mind that there are also changes due to rains, winds and other factors that are not linked to the tides.
To the continuous and slow ascent of marine waters it is called flow . When the sea reaches its maximum height, it reaches the high tide or high tide . From this point on, the progressive descent , called Reflux . The minimum height, meanwhile, is called low tide or Low tide . Then the flow develops again and so on.
From high tide to low tide (and vice versa) approximately six hours . It should be noted that the flow is due to the progressive increase of solar and / or lunar attraction, while reflux is related to the progressive decrease of said attraction .
Is called red tide , on the other hand, to the spread of microalgae in the Water in a given region These microorganisms generate toxins that affect mollusks: if a person later ingests these animals, they can be poisoned.
The black tide Finally, it appears when a spill occurs. Petroleum in water. These accidents damage the ecosystem in various ways.