What Causes Ocean Tides: Detailed Overview

Not all, but many of our world's oceans experience ocean tides influencing the sea level and the surf. But what causes ocean tides?

Are ocean tides important? How does the moon affect ocean tides?

All these questions will be covered in this article. Let’s begin!

What Causes Tides?

The main factor that causes ocean tides is the gravitational pull of the moon and the sun on Earth's oceans.

Other factors that causes ocean tides will depend on location but this is the main the reason the ocean tide comes in and out.

What Are Ocean Tides

Ocean tides refer to the regular rise and fall of sea levels caused by gravitational forces between the Earth, the moon, and the sun. 

The moon's gravitational pull is the primary driver of tides, creating two high tides and two low tides during a 24-hour period. 

As the moon orbits the Earth, it creates a bulge of water on the side facing the moon, resulting in high tide, while a second high tide occurs on the opposite side due to centrifugal force. 

The areas between these bulges experience low tide. This gravitational dance that causes ocean tides, also influenced by the sun, gives us the flow of ocean tides we observe daily. 

Why do not all beaches have ocean tides? 

Not all beaches experience ocean tides in the same way because tidal patterns depend on geographical factors, including the beach's location and the shape of the coastline. 

Some inland seas or enclosed bays may have limited tidal influence compared to open coastlines, leading to variations in tidal behaviour from beach to beach.

What Causes Ocean Tides

The gravitational interaction between the Earth, the moon, and the sun causes ocean tides to occur.

The moon's gravitational pull is especially influential, although much smaller than Earth's, its proximity leads to significant effects that causes ocean tides.

As the Earth and moon orbit each other, the gravitational forces create a tidal bulge on the side of the Earth facing the moon. 

Simultaneously, there's another bulge on the opposite side due to the centrifugal force from the Earth-moon system's rotation. These gravitational forces, along with the sun's influence, result in the predictable rhythm of high and low tides we observe. 

Tidal Force

Tidal force is a gravitational phenomenon that arises from the interaction between celestial bodies, particularly the Earth, moon, and sun. This force is what causes ocean tides. 

The moon's gravitational pull generates a tidal force, creating a bulge of water on the side of the Earth facing the moon and a second bulge on the opposite side due to centrifugal force.

This force is not only exerted by the moon but also influenced by the sun which in turn causes ocean tides.

When the gravitational forces align, they intensify, leading to higher high tides and lower low tides. 

How Are Tides Formed

Tides are formed through the gravitational pull exerted by celestial bodies, mainly the moon and the sun, on Earth's oceans. 

As the Earth and moon orbit each other, the gravitational forces create a tidal bulge on the side facing the moon and another bulge on the opposite side due to centrifugal force. 

This results in two high tides and two low tides in a 24-hour period influencing sea levels throughout the day. The sun also contributes to tidal formation, though to a lesser extent.

High and Low Tides

Tides are the regular rise and fall of sea levels, creating high and low tides in a rhythmic pattern.

What Causes High Tides

High tides occur when the gravitational pull of the moon and sun align, creating a bulge of water on the side of the Earth facing the moon and a second bulge on the opposite side due to centrifugal force. 

This alignment intensifies the gravitational forces, leading to higher high tides.

What Causes Low Tides

Low tides, on the other hand, happen when the Earth, moon, and sun form a right angle, resulting in less gravitational pull on Earth's waters. 

This configuration creates periods of reduced gravitational force, leading to lower water levels known as low tides and also overall causes ocean tides.

What Is a Spring Tide

A spring tide is an extraordinary variation in the ocean's tidal range, characterised by higher high tides and lower low tides. 

This phenomenon occurs during the new moon and full moon phases when the Earth, moon, and sun are aligned, intensifying their gravitational forces on Earth's oceans.

During a spring tide, the combined gravitational pull of the moon and sun creates a more pronounced tidal bulge, leading to higher high tides. Conversely, the low tides during a spring tide are lower than usual due to the increased gravitational forces. 

Ebb Tides

Ebb tides are the reverse of flood tides and signify the seaward movement of water. 

They occur between high tide and low tide as the gravitational forces of the moon and sun lessen. 

During ebb tides, water recedes from the shorelines, revealing more of the seabed. This phase is integral for coastal ecosystems and activities like beachcombing. 

Intertidal Life

Intertidal life refers to the diverse ecosystems existing in the area between the high and low tide marks along coastlines. 

This dynamic zone, also known as the intertidal zone, experiences fluctuating conditions due to the regular rise and fall of tides. 

Organisms in this environment, such as barnacles, crabs, and sea anemones, have adapted to withstand exposure to air during low tide and immersion in seawater during high tide.

The intertidal zone serves as a critical habitat for numerous marine species and plays a vital role in coastal ecosystems.

How Does The Moon Cause Tides

The moon causes tides through its gravitational influence on Earth's oceans. 

As the moon orbits our planet, its gravitational pull creates a tidal bulge on the side facing the moon and another on the opposite side due to centrifugal force. 

This gravitational dance results in two high tides and two low tides during a 24-hour period.

Why Are Tides Higher During a Full Moon

Tides are higher during a full moon due to the alignment of the Earth, moon, and sun. When the sun and moon are on opposite sides of the Earth, their gravitational forces align, reinforcing each other. 

This alignment intensifies the tidal bulges, leading to higher high tides and lower low tides. The full moon's position enhances the gravitational pull, creating a more pronounced tidal effect, known as spring tides. 

Does Anything Else Affect Tides?

Wind: Strong winds can push water towards the shore, causing a temporary rise in sea level known as a wind tide. 

Atmospheric Pressure: Changes in atmospheric pressure can also impact sea levels. Low pressure can cause a slight elevation in sea level, while high pressure can lead to a slight depression.

Geography: The shape of coastlines and the ocean floor can influence the amplitude of tides. Narrow, shallow bays may experience higher tides than open coastlines due to the funnelling effect of the water.

Coriolis Effect: The rotation of the Earth causes a deflection of moving fluids, including ocean water. This Coriolis effect can influence the direction and intensity of tidal currents.

Tides and Surfers

Tides influence wave conditions, with high tide often providing powerful and consistent waves suitable for surfing. 

In turn, factors that causes ocean tides also cause different surfing conditions

Low tide, on the other hand, may reveal sandbars and create faster, hollower waves. 

Surfers often check tide charts to plan their sessions, ensuring they align with optimal tide conditions for their preferred surfing experience. Tides play a pivotal role in shaping the surfing landscape and contribute to the thrill and excitement of the sport.

Tidal Bores

Tidal bores are extraordinary phenomena where incoming tides create powerful, upstream river surges. 

One of the most famous tidal bores occurs on the Qiantang River in China, known for its colossal "Silver Dragon" bore during the mid-autumn festival.

In England, the Severn Bore is renowned for its dramatic surges, attracting surfers to ride the tidal wave upstream. 

Tidal Flats: Mud Warning!

Surfers should exercise caution around tidal flats, especially during low tide, as the receding water can expose muddy areas. 

These mudflats can pose risks of entrapment, making it essential for surfers to be mindful of their surroundings and avoid venturing into potentially hazardous conditions.

Summing It Up: What To Do Now

Nice! Now you understand what causes ocean tides and how each factors causes ocean tides to be stronger than others.

If your interested in learning more about surfing discover our many guides that will inform you on your surfing journey. Don't forget to follow us on Facebook & Instagram to stay informed on our amazing surf shots and stories shared from surf creators around the world!