Beach (also beachfront, shoreline, and coastline) is a landform alongside a body of water that consists of loose particles of rock, such as sand, gravel, cobbles, pebbles, shells, and coralline algae. The beach’s shape and structure depend on wave action, weather conditions, and the composition of its material. Beaches are often popular for recreation, with facilities such as lifeguard posts, showers, shacks, and bars. They are also important habitats for marine organisms and a source of food for birds, insects, and mammals. Beaches may also serve as a buffer between the land and sea, preventing erosion of the underlying shore.
A sandbar is a long mass or low ridge of submerged or partially exposed sand built up in an area along a beach by the action of waves and currents. They are often curved or horseshoe-shaped. They form when a current moving toward the beach meets a current pushing out to sea, and the sand carried by both of these forces sinks into the water. Bars can also form in bays and other enclosed areas, as well as in river mouths where the water meets the sea.
Many beaches contain finer particles than sand, such as pebbles, shells, and even coarse coralline algae. These particles can be sorted into different sizes by the action of currents and waves, creating sandy, shingle, or gravel beaches. A beach’s slope is determined by the size of its particle; the smaller the particles, the flatter the beach. The sand or shingle is then further shaped by wind and water, producing different textures, gradients, and coloration of the beach.
In coastal erosion, beaches are particularly important because of the energy that they dissipate in the water and on the land. The sand, silt, and organic materials they contain slow the flow of water, helping to stabilize coastal features. They also provide a place for runoff from the land to be deposited, which can then feed the flora of the coastal zone.
Humans can alter the course of a beach’s evolution by building structures to limit its erosion, such as seawalls or breakwaters. However, these changes can have a negative impact on wildlife, such as sea gulls that scavenge trash or are killed by floating plastic. Beachgoers can help protect the beach by reducing litter and leaving live animals alone.
Many beachgoers contribute to the health of beaches by recycling, reducing their use of fossil fuels, and avoiding areas that are closed to the public due to environmental hazards such as dangerous sea urchins or sharks. They can also help by reducing their consumption of seafood from the beach and leaving shells, crabs, and other marine organisms alone. In addition, it is always a good idea to swim in shallow waters away from the beach and to never take live organisms from the ocean. Lastly, it is important to remember that even wild sand and shingle beaches are homes for many species of plants, animals, and birds.