A beach is the area along a body of water, such as an ocean, lake, river or even a large pond that is characterized by loose bits and fragments of material, mostly sediments. The sediments, which may be sand, gravel, pebbles, cobbles, or boulders, are the result of wave erosion and deposition, and a combination of these factors that shape the beach over time. Beaches are not only important recreational areas for humans but also provide habitat for marine organisms. From tiny hermit crabs scurrying across the sand to colorful fish swimming in the waves, beaches are home to many fascinating species.
A beach has several distinct parts when viewed from the air or from waterline level: a crest (top) with a face, and a flat, low portion known as the backshore. In addition, a beach may contain sand dunes that lie either within or adjacent to the beach. Finally, a beach can include nearshore bars, which are slightly raised areas of sediments just offshore.
While most people associate beaches with oceans, they can actually be found along the shorelines of lakes, rivers, and other bodies of water. The most common feature of a beach is the accumulation of loose sediments like sand and pebbles, which are transported by waves and currents over long periods of time and ultimately build up and form a coastline. Beaches are not only important recreational and economic areas for humans, but they also serve as home to numerous marine organisms.
The materials that comprise a beach vary from region to region, but sand is the most commonly observed component. Beach sand can be geological in origin, resulting from the weathering of rocks onshore, or biological in nature, resulting from the breakdown of coral skeletons and other hard shells of marine organisms. Most beaches have a mix of these two types of sand, but the proportion of each will depend on the intensity of waves and winds.
Sand particles on a beach tend to compact if there is a sufficiently long period between the wave crests. This causes the sediments to become more resistant to erosion by the turbulent water of succeeding waves. Conversely, a beach with relatively short wave periods will have finer and more mobile sediments.
A beach may also contain a range of other sediments, such toto sdy as clay and silt. These may be deposited by rain or river runoff, or may be the result of erosion from the cliffs above the beach. In addition, a beach may contain organic material from decaying plant matter or animal remains. In the case of a man-made beach, these can include garbage and other waste that has been carried to the coast by storms. Beaches are not only vital recreation areas for humans, but they also play an important economic and cultural role in many communities around the world. Many beaches have extensive facilities, including lifeguard posts, showers, changing rooms, and a variety of hospitality venues for visitors.