Lagoon vs. Lake

What's the Difference?

Lagoons and lakes are both bodies of water, but they differ in several ways. Lagoons are shallow, coastal water bodies that are usually separated from the ocean by a barrier such as a sandbar or coral reef. They are typically brackish or saline, meaning they have a mixture of saltwater and freshwater. Lagoons are often found in tropical or subtropical regions and are known for their rich biodiversity. On the other hand, lakes are inland bodies of freshwater that are surrounded by land. They can vary in size and depth, and are usually fed by rivers or underground springs. Lakes are home to a wide range of plant and animal species and are often used for recreational activities such as swimming, boating, and fishing.


Photo by Saul Mercado on Unsplash
DefinitionA shallow body of water separated from a larger body of water by a barrier such as a sandbar, coral reef, or barrier island.A large body of water surrounded by land.
FormationFormed by coastal processes, such as the accumulation of sediments or the submergence of a coastal landform.Formed by various geological processes, such as tectonic activity, glacial activity, or volcanic activity.
SizeUsually smaller in size compared to lakes.Can vary greatly in size, ranging from small to large.
SalinityCan be saline, brackish, or freshwater.Can be saline, brackish, or freshwater.
Connection to the OceanDirectly connected to the ocean through inlets or channels.May or may not have a direct connection to the ocean.
Flora and FaunaSupports a unique ecosystem with specialized plant and animal species adapted to the lagoon environment.Supports a diverse range of plant and animal species, which can vary depending on the specific lake ecosystem.
Human ActivitiesUsed for recreational activities such as swimming, boating, and fishing. Can also be impacted by human development and pollution.Used for recreational activities such as swimming, boating, and fishing. Can also be impacted by human development and pollution.
Photo by Alice Triquet on Unsplash

Further Detail


When it comes to natural water bodies, lagoons and lakes are two distinct features that often capture our attention. Both lagoons and lakes are formed through various geological processes, yet they possess unique characteristics that set them apart. In this article, we will explore the attributes of lagoons and lakes, highlighting their differences and similarities.

Formation and Geography

Lagoons are typically shallow bodies of water that are separated from the open sea by a barrier, such as a sandbar, coral reef, or barrier island. They are often found along coastlines and are influenced by both freshwater and saltwater sources. Lagoons can be formed by the accumulation of sediments, volcanic activity, or the submergence of coastal areas due to rising sea levels.

Lakes, on the other hand, are inland bodies of water that are usually surrounded by land. They can be formed through various processes, including tectonic activity, glacial activity, volcanic activity, or even human-made reservoirs. Lakes can range in size from small ponds to vast expanses of water, such as the Great Lakes in North America.

Size and Depth

When comparing lagoons and lakes, one noticeable difference is their size and depth. Lagoons are generally shallower than lakes, with an average depth of a few meters. Due to their shallow nature, lagoons often have warmer water temperatures compared to lakes. In contrast, lakes can vary significantly in depth, with some reaching hundreds of meters deep. The depth of lakes allows for the formation of distinct thermal layers, with colder water at the bottom and warmer water near the surface.

Water Source and Salinity

Another significant difference between lagoons and lakes lies in their water source and salinity. Lagoons are influenced by both freshwater and saltwater sources, making their salinity levels variable. The mixing of freshwater and saltwater creates a unique ecosystem that supports diverse marine life. In contrast, lakes are primarily fed by freshwater sources, such as rivers, streams, or underground springs. As a result, lakes tend to have lower salinity levels compared to lagoons.

Ecological Importance

Both lagoons and lakes play crucial roles in supporting various ecosystems and providing habitats for numerous plant and animal species. Lagoons, with their brackish water, are often home to a rich diversity of marine life, including fish, crustaceans, and various types of algae. They also serve as important breeding grounds for migratory birds and provide shelter for many coastal species.

Lakes, on the other hand, support a wide range of freshwater species, including fish, amphibians, and aquatic plants. They contribute to the overall biodiversity of an area and are often surrounded by wetlands, which further enhance their ecological importance. Lakes also serve as water sources for human consumption, irrigation, and recreational activities such as boating and fishing.

Human Interaction and Uses

Due to their unique characteristics, both lagoons and lakes have attracted human settlements and activities throughout history. Lagoons, with their proximity to the coast, have often been utilized for fishing, aquaculture, and tourism. They offer opportunities for water sports, such as kayaking, snorkeling, and swimming. Additionally, lagoons can provide protection against coastal erosion and storm surges.

Lakes, on the other hand, have been utilized for various purposes, including drinking water supply, irrigation for agriculture, hydroelectric power generation, and recreational activities. Many lakes have become popular tourist destinations, offering opportunities for boating, sailing, and camping. Some lakes also hold cultural and spiritual significance for local communities.


In conclusion, lagoons and lakes are distinct water bodies with unique attributes. Lagoons are shallow, coastal bodies of water influenced by both freshwater and saltwater sources, while lakes are inland bodies of water primarily fed by freshwater. Lagoons tend to have higher salinity levels and support diverse marine life, while lakes have lower salinity levels and are home to various freshwater species. Both lagoons and lakes have ecological importance and provide numerous benefits to human societies. Understanding the differences and similarities between these two water bodies allows us to appreciate their beauty and significance in our natural world.

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