Coastal geography

The land meets the sea.

Waves hit the shore. Strong waves can carry sand away. Weak waves build the beach up.

Waves hit the sand at an angle. This moves sand down the beach. This can make long strips of sand. Wind can also blow sand into hills.

The sea level goes up and down. This happens when the world gets warm or cold. The coast is always changing.

Coastal geography is the study of the coast. It looks at the area where land meets the sea. This place is always changing.

Waves are the main movers of the coast. Strong waves are called destructive waves. They carry sand away from the beach. Weak waves are called constructive waves. They pile sand up to make the beach bigger.

Waves often hit the shore at an angle. This causes longshore drift. This is a way that sand moves along the beach. The water pushes sand up at an angle. Then gravity pulls the water straight back. This cycle moves sand in one direction. It can make long strips of coast.

Wind also helps. Onshore winds blow sand up to make dunes. Other things change the coast too. Rain can wear down rocks. In warm places, plants and animals can change the land. Even salt can break rocks. Salt gets into cracks. When the water dries, the salt grows. This creates pressure that breaks the rock.

Coastal geography is the study of the changing area where land meets the sea. It looks at how the physical world and people interact at the coast. Scientists study the shape of the land and the weather. They also look at how the ocean works. This includes studying how waves move and how rocks break down. People also study the history of these places. Understanding the coast helps us know how it changes over time.

Waves are the main tools that shape the shoreline. Different waves do different jobs on the beach. Strong waves are called destructive waves. They usually happen in the winter on high-energy beaches. These waves carry sand away to parts of the sea called bars. Weak waves are called constructive waves. They usually happen in the summer on low-energy beaches. These waves pile sand up to make the beach bigger.

One important way sand moves is through longshore drift. This happens because waves rarely hit the shore at a straight angle. The water carries sand up the beach at an angle called swash. Then, gravity pulls the water straight back down the beach. This movement is called backwash. This cycle moves sand sideways along the coast. This process can create long strips of sand. It also helps make landforms like spits and barrier islands.

Many other things can change the shape of the coast. Onshore winds blow sand up to create sand dunes. Rain can hit rocks and wash them away. In tropical areas, living things can change the land too. Some plants and animals protect rocks, while others eat them away. Even salt can break rocks through salt-crystal growth. Salt spray gets into cracks in the rock. When the water dries, the salt crystals grow and create pressure.

Finally, the level of the sea and land can change. Sea levels rise and fall because of climate changes. During cold times, water stays as ice in glaciers. During warm times, the ice melts and the sea rises. About 18,000 years ago, sea levels were very low. The movement of tectonic plates can also change the land. In the U.K., the land is changing right now. The southeast is sinking by about 2 mm every year. Meanwhile, northeast Scotland is rising by that same amount.

Coastal geography is the study of the constantly changing region where the ocean meets the land. This field is quite broad because it includes both physical and human geography. Physical geography focuses on coastal geomorphology, which is the study of landforms. It also looks at climatology and oceanography to understand the environment. Human geography explores the sociology and history of how people interact with these coasts. By studying these areas, we can understand how weathering and sediment movement shape our world.

Waves are the primary movers and shapers of the coastline. The strength of these waves determines how they affect the beach. Strong waves are known as destructive waves. These are typical of high-energy beaches during the winter months. Destructive waves reduce the amount of sediment on a beach by carrying it out to underwater bars. In contrast, weak waves are called constructive waves. These are common on low-energy beaches during the summer. Constructive waves increase the size of the beach by piling sediment up onto a berm.

One of the most important transport mechanisms is called longshore drift, or littoral drift. This process moves sediment continuously along a beach through wave action. It begins when waves hit the shore at an oblique angle. The water carries sand up the beach at an angle in a movement called swash. Gravity then pulls the water straight back down the beach in a perpendicular direction. This return flow is called backwash. This endless cycle of swash and backwash moves beach material laterally. This movement is why long strips of coast are covered in sediment.

Longshore drift is essential for creating many different landforms. These include barrier islands, bay beaches, and spits. This process generally works to straighten the coastline over time. It does this by creating barriers that cut off bays from the open sea. In bays, waves are often weaker due to wave refraction. This allows sediment to build up and protect the bay from further erosion. Meanwhile, sediment is often carried away from exposed headlands. This lack of sediment makes headlands more vulnerable to weathering.

Many atmospheric and biological processes also impact the coast. Onshore winds can blow sand up the beach to form sand dunes. Rain can erode rocks and carry weathered material to the shoreline. In tropical regions, biological processes play a major role. Some organisms protect stones from weathering, while others actually eat away at the rocks. Many organisms have shells made of calcium carbonate. When these are broken down, they form sediment, clay, or limestone. Physical processes like salt-crystal growth also break down rocks. Salt spray enters cracks in the rock and evaporates. The resulting salt crystals create pressure that breaks the rock apart.

Sea levels on Earth change regularly due to eustatic change. This refers to global changes in sea level caused by climatic shifts. During cold periods, more water is stored in glaciers as ice. During warm periods, this ice melts and sea levels rise. For example, sea levels were quite low 18,000 years ago during the Pleistocene ice age. Currently, sea levels are quite high. Global warming may cause further rises in the future. This presents a risk to coastal cities because even small rises can cause flooding. Rising seas can also create new landforms like fjords and rias.

Land levels can also change through a process called isostatic change. This happens when the land rises or falls due to tectonic pressure or ice weight. In the United Kingdom, this is very visible. During the last ice age, ice sheets covered much of the land. The massive weight caused northeast Scotland to sink. This displacement forced the southeast of the country to rise. As the ice receded, the process reversed. Today, the southeast is sinking at about 2 mm per year. At the same time, northeast Scotland is rising by that same amount.

Spits are unique landforms that form when a coast suddenly changes direction. Longshore drift pushes sediment along the beach until it reaches a turn. If the sediment cannot easily turn, it begins to accumulate. This often happens near an estuary where river currents might push sediment away. Over time, the sediment builds up to form a barrier of sand extending into the sea. Sometimes, a change in wind direction can cause the spit to grow backward, forming a hook. If a spit grows all the way across a bay, it is called a bar. When a bar joins an island to the mainland, it is known as a tombolo.