A beach is a strip of land along the edge of an ocean, sea or river that is made up of materials such as sand pebbles rock and shell fragments. The type of material that makes up a beach depends on the geology of the area where it is located.
Beaches are always moving and changing, as they are constantly accumulating sediment or being reworked by currents. This action can change beaches forever from one day to the next, bringing new materials and taking away others.
Tides and ocean currents move sand hundreds of kilometers from their source in the mountains, to the sea where it becomes a beach. This natural process of sediment transport can be very important to the survival of beaches.
Most beach sand is a mixture of tiny particles of weathered quartz from the Appalachian Mountains, and bits of rocks that have been eroded in the Gulf of Mexico and elsewhere. This sediment mix is carried to the beach by the wind and water, and if it hasn’t been iron-stained (oxidized like rust) it will be white. If it has been, the beach will be a brownish color or black.
Sediment on a beach tends to indicate the energy of waves and winds in the region. If a beach has long periods between wave crests, the fine sediment can compact and be resistant to erosion by receding tides and longshore currents. However, if the period between wave crests is short, the fine sediment will remain in suspension and become susceptible to wave action.
The size of the sediments that make up a beach can also tell you how much wave and wind energy it has. Smaller sediments are able to be transported by the waves, while larger ones are not.
When the sand is protected by a fence or barrier, most of the smaller sediments are not swept away. They are deposited onto the beach instead, making the beach more sandy.
Another way that the beach is created, changed, and destroyed is by storms. Strong, fast, and heavy storms can bring in new sand to the area. This can change the way a beach looks and how much it is used.
Beaches can change their width, slope, and composition, all within an hour or even a few minutes of a storm. Some beaches are narrow and flat, while others are wide and steep.
The width of a beach can change from one time to the next because of changes in the sea level, tides and currents, and wind. The slope of a beach can change from steep to gentle, depending on the nature of the sand and the type of sand that it contains.
There are many kinds of beach flora and plant species. Some of these plants, such as sand tiger palms, have large root balls that help to stabilize the sand dunes and protect them from coastal erosion. Other plants, such as oleanders, are adapted to beaches and grow best on sand dunes.