Beaches are one of the most popular tourist destinations in the world. Millions of people flock to the coast yearly to enjoy the sun, sand, and waves. But have you ever noticed that some beaches have crystal clear water while others have murky or even downright dirty water?
It turns out that a few factors can influence the clarity of the water at a beach. Let’s take look at why some beaches have clear water and others don’t.
Proximity to a River or Stream
The main factors are the proximity to a river or stream. Beaches located near a river or stream are more likely to have murky or cloudy water. That’s because rivers and streams carry sediment and other pollutants from upstream, eventually making their way into the ocean.
Since the water at sea is constantly in motion, the sediment does not settle at the bottom, but they are continually getting stirred up. So, even if the water at a beach looks clear when you first arrive, it can quickly become cloudy if there is a lot of activity in the water.
Also, Caribbean beach water is warm, and it is hard for algae to grow in warm water. The lack of algae also gives the water a more clear appearance.
Additionally, the sediments from the river also contain nutrients that feed sea plants, such as algae. These nutrients can cause algae blooms, making the water appear mild tint or green.
On the other hand, beaches that are far from any rivers or streams tend to have much clearer water. That’s because the water has had time to settle, and the sediments have been carried away by the currents.
The Power of Barrier Reefs in Keeping Water Clear
A very important reason beaches in and around the Caribbean are clear is because many barrier reefs protect these beaches. As a result, these barrier reefs mitigate the flow of water into the beach area, so the water is clear and free from sediments and the water being stirred up.
So in essence, the water is more like a swimming pool because the water flow is reduced by these barriers. So the sediment is not churned up in the water like it is on beach that don’t have this protective barrier.
Regions such as the Dominican Republic and Bahamas have reefs and other physical structures that act as barriers. By the time the waves reach these beaches, they are much weaker, and the sediments have already been deposited. As a result, the water at these beaches is usually much clearer.
The Earth’s Rotation
The earth’s rotation also affects how clear the water is at a beach. As the earth rotates, it creates currents in the oceans that travel from west to east. The water movement creates a phenomenon known as upwelling, which brings deep, nutrient-rich water to the surface.
This deep water is usually colder and darker than the water at the surface. Additionally, it often contains a lot of sediment picked up from the seafloor. It makes the water at the beach appear cloudy or even muddy.
However, upwelling only happens in some regions of the world. The process is most common along the coasts of Japan, Australia, the Philippines, East Africa, the USA, Chile, and western Mexico. These areas have large continental shelves, allowing deep water closer to the surface.
Regions such Dominican Republic and Bahamas have reefs and other physical structures that act as barriers. By the time the waves reach these beaches, they are much weaker, and the sediments have already been deposited. As a result, the water at these beaches is usually much clearer.
Next time you’re on holiday, you will know why some beaches have clearer water than others!
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