The tides are the rise and fall of the ocean water level. This phenomenon has a great impact on both marine and terrestrial life. But what causes tides? To understand their origin, we must look to the sky. They are the sun and moon those responsible for the tides, and the waves generated by these forces are known as tsunamis.
How are tides produced?
Tides are produced by the gravitational attraction that celestial bodies, mainly the Moon and the Sol, exert on the Earth and its oceans. Gravitational force creates a difference in water levels depending on depth, proximity to the coast, and other geographic features of the region.
Even though the Sun is much larger than the Moon, it is the Earth’s satellite that has a greater influence on the tides, and this is due to its relative proximity to the Earth. Every day, the water experiences two cycles of high and low tide. These cycles are divided into high tides y low tides, with an approximate period of 12 hours between each one.
Forces that generate tides
The explanation of the tides is based on the combination of two main forces: gravitational and centrifugal.
- The gravity of the Moon and the Sun: This force attracts masses of water towards the nearest star, generating high tides at the points on Earth closest to the Moon and the Sun.
- Centrifugal force: Produced by the rotation of the Earth, it balances the gravitational effect at points opposite to those where high tides are experienced, also creating tides on the opposite side of the planet.
Thus, the result is that in the same day we can notice from the coast two high tides and two low tides. Curiously, the highest tides occur when the Sun, the Moon and the Earth are aligned (full or new moon), which is known as spring tides.
Spring tides and neap tides
The spring tides occur when the Sun, Moon and Earth are almost aligned. This occurs during the full moon and the new Moon. In these phases, the forces of gravitational attraction combine, producing especially high and low tides. On the other hand, when the stars form a right angle, the forces counteract each other, giving rise to neap tides, where small rises and falls in sea level are observed.
The cycle of a lunar day
The complete tidal cycle follows what is known as lunar day, instead of a 24-hour solar day. The Earth takes approximately 24 50 hours and minutes in completing a cycle with respect to the Moon, which explains why the tidal schedule changes slightly each day.
Over the course of these 24 hours and 50 minutes, each point on Earth experiences two high tides and two low tides, due to the Earth’s rotation and the interaction between gravitational and centrifugal forces.
Impact of tides on marine and terrestrial life
Tides have a major impact on marine life, affecting everything from species migration to nutrient distribution. During low tide, many marine species are exposed to or must adapt to reduced aquatic habitat, while high tides provide new expansions of territory, allowing for the feeding and reproduction of a greater diversity of marine life.
- Intertidal ecosystems: In coastal regions, plants and animals that inhabit the intertidal zone have adapted to living both submerged and exposed to the air. Crabs, mollusks and algae are found within this environment, which changes every day with the tides.
- Fish and marine mammals: The location and life patterns of many species depend on tidal cycles. Schools of fish often move closer to shore at high tides, providing food for larger animals such as sharks, dolphins and seabirds.
The practical utility of tides
Tides not only influence marine life. They also have a considerable impact on activities such as navigation and the fishery, being very useful to predict optimal conditions for both activities.
In addition, its energy is used in tidal power plants that generate electricity. Although this technology is still under development, its sustainability is promising. tidal power plants They convert the kinetic energy of the tides into electricity, taking advantage of the natural ebbs and flows of water.
How to predict tides
Today, tide prediction is an essential tool in several industries, from fishing to boating. Through tide tables, it is possible to know the exact times of high and low tide. These tables are the result of calculations made from astronomical and local observations, and today they can be easily consulted online or through mobile applications.
By knowing the timing of the tides, fishermen can plan to catch species that approach the coast during high tide, while surfers can take advantage of the waves generated by high tides.
Finally, tides are a fundamental natural phenomenon that connects celestial bodies to life on Earth. From their effects on marine life and human activities to their potential as a source of renewable energy, their influence is vast. Understanding how they are produced and how they affect us is essential to harnessing their benefits sustainably and safely.