A beach is an area of land that stretches along the edge of a body of water. It is made of a variety of materials, including sand, pebbles, and shingle. These materials are moved on and off the beach due to wave action. There are different kinds of beaches, and they can be hundreds of kilometers long. Beaches are also referred to as coasts.
A beach is made of tiny pieces of rock and other materials that have been eroded by the action of water. This sand is a result of coral reefs, but it is not the only source of sand. Weathering also plays a big role in determining how a beach looks. Waves can knock rocks loose and reduce huge boulders to tiny grains of sand.
Fine-grained beaches generally have a gentler slope and are better able to absorb water. While fine sand absorbs little water, most of the water flowing up the beach flows back down again. This process is called backwash, and it moves the sand in a seaward direction. On the other hand, coarse sand beaches absorb more water and move it up and down the beach.
The beach environment can also support a variety of animals. Birds are common on beaches, and they use the sand to build nests and lay eggs. Seals also use beaches for feeding and protection from predators, such as sharks. Crabs are another animal that lives on the beach. They help keep the beach clean by going into the water to clean the sand. The sea grasses that grow on the shore are home to sea turtles.
Beach sand is often made up of minerals like quartz and feldspar. They form less than one percent of the grain, but are visible on the surface of the beach. Mica flakes add sparkle to the surface of the beach. When waves swash over them, the mica grains are suspended on the surface, creating a sparkle.
Sand beaches make up approximately one-third of the world’s coastlines, and play important recreational and cultural roles. They also often drive local tourism industries. Some have manmade infrastructure, such as changing rooms, showers, and lifeguard posts. Others are populated by resorts, where people can practice water sports. A beach is a great place to relax.
The surface of the beach is constantly changing and forming new features. A beach’s bedforms vary greatly depending on its location and tidal cycles. Figure 2.1 shows an example of a beach’s berm. In some areas, this structure may be accompanied by a trough or a long shore bar.
Beaches are especially susceptible to pollution. The waves wash debris into the ocean, and sewage and other waste from inland areas into the sea. Some of this debris contains toxic chemicals and bacteria that can harm humans. These toxins can take several days to wash out to sea.