Lagoon

A lagoon is a shallow pool of water.

It sits next to the big ocean. A thin strip of land keeps it safe. This land can be a reef or small islands.

The water can be salty or fresh. Some lagoons are very long. They can form near many coasts. They are found in many parts of the world.

Lagoons are very special places to see.

A lagoon is a shallow body of water.

It sits next to a larger body of water, like an ocean. A narrow piece of land keeps them apart. This land might be a reef or a barrier island.

There are two main types of lagoons. One type is a coastal lagoon. These form along coasts with gentle slopes. They can be leaky or choked. This means they have many or few paths to the sea.

The water can be salty or fresh. It depends on how much fresh water flows in. It also depends on how much water evaporates.

The other type is an atoll lagoon.

These form around coral reefs. As the reefs grow up, the islands sink down. Eventually, only the reef stays above the sea. This leaves a lagoon in the middle. These lagoons can be quite deep. Lagoons are common. They are found along 15 percent of the world's shorelines.

A lagoon is a shallow body of water.

It sits next to a much larger body of water. A narrow piece of land separates the two. This land might be a coral reef or a barrier island.

Some people call these areas estuaries. However, experts often use different names for them. A lagoon is usually long and runs along the coast. An estuary is often a river valley that has flooded. These water bodies are very common around our world.

There are two main ways these lagoons form. Atoll lagoons happen around coral reefs. First, the reefs grow upward toward the sun. Next, the islands they surround begin to sink down. Eventually, only the ring of reef stays above the water.

This leaves a lagoon in the middle. Coastal lagoons form in a different way. They appear along coasts that slope very gently. Barrier islands or reefs develop far from the shore. As sea levels rise, these areas become shallow lagoons.

People have studied these places for a long time. The word lagoon comes from the Venetian word "laguna." This name refers to the waters around Venice, Italy.

English speakers began using the word by 1612. In 1697, William Dampier wrote about a salt water lagoon in Mexico. Later, Captain James Cook described an island with a lagoon in 1769. These explorers helped us learn about different types of water. They saw how lagoons look in many different lands. Many different languages have their own special names for them.

Lagoons can be found in many different places. They exist along nearly 15 percent of the world's shorelines. In the United States, they cover 75 percent of the Eastern and Gulf Coasts.

Some lagoons are very large, like Lake Maracaibo. Other lagoons are part of big systems like the Pamlico Sound. The water in a lagoon can be salty or fresh. This depends on how much fresh water flows in. It also depends on how much water evaporates away. Some lagoons have many inlets to the ocean. Others have very few paths to the sea.

Lagoons are part of a changing world. They are often young and can change quickly.

If the sea level drops, a lagoon might dry up. If the sea level rises, the ocean might break the barrier. This can leave the reefs too deep to protect the water. Many things help build up the floor of a lagoon. Rivers carry sediment, which is sand or mud, into the water. Storm waves can also wash sand over the barrier islands. Plants like mangroves help trap this sediment in place. This makes the lagoon a very busy place for nature.

A lagoon is a shallow body of water separated from a larger body of water by a narrow landform. This barrier might be a coral reef, a barrier island, or an isthmus. Lagoons are common coastal features found throughout the world. They play a major role in coastal ecosystems. Scientists often divide them into two main categories: coastal lagoons and atoll lagoons.

Coastal lagoons form along coasts with very gentle slopes. These lagoons appear when barrier islands or reefs develop offshore. This process often happens when sea levels rise relative to the land. This rise can be caused by the ocean rising or the land sinking. Because the coast slopes so gently, these lagoons remain quite shallow. They do not form along steep or rocky coasts.

Atoll lagoons form through a different biological and geological process. These lagoons develop as coral reefs grow upward toward the surface. While the reefs grow, the islands they surround begin to subside, or sink. Eventually, only the ring of coral reef remains above the sea level. This leaves a body of water in the center. Unlike coastal lagoons, atoll lagoons often contain deep portions.

Researchers sometimes debate the exact definition of a lagoon. Some authorities include fresh water bodies in the definition. Others say a lagoon must have some level of salinity, or saltiness. There is also a distinction between a lagoon and an estuary. Richard A. Davis Jr. suggests that lagoons have little fresh water inflow. He defines an estuary as a bay that receives regular fresh water. Timothy M. Kusky notes that lagoons are usually elongated parallel to the coast. In contrast, estuaries are often drowned river valleys perpendicular to the coast.

The term lagoon has a long history in the English language. It is derived from the Venetian word "laguna." This refers to the waters surrounding Venice, Italy. The word "laguna" was used in English by at least 1612. In 1697, William Dampier described a salt water lagoon in Mexico. Later, in 1769, Captain James Cook described an island with a lagoon in the middle.

Lagoons are incredibly widespread across the globe. They occur along nearly 15 percent of the world's shorelines. In the United States, they are found along more than 75 percent of the Eastern and Gulf Coasts. Coastal lagoons can be classified as leaky, restricted, or choked. Their water chemistry depends on several moving parts. For example, Lake St. Lucia in South Africa can become highly saline. This happens due to high evaporation and little ocean interchange. Conversely, the Wadden Sea has many wide inlets. These inlets create strong tidal currents that mix the water.

Many different factors influence the physical structure of a lagoon. Lagoons accumulate sediment from inflowing rivers and shoreline runoff. Tides also carry sediment through inlets into the lagoon. Large amounts of sediment may arrive during storm waves. These waves can wash material over barrier islands. Plants like mangroves and marsh plants help facilitate sediment accumulation. Additionally, benthic organisms can stabilize or destabilize these sediments. This makes lagoons dynamic and often short-lived in geological terms.