Lagoon vs Lake: What’s the Difference?

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People mix up lagoon vs lake because both are calm, enclosed stretches of water that look similar in photos. Some lagoons even have “lake” in their names, which makes things worse. The real difference is how each one relates to the sea.

What does “lake” mean?

A lake is a large body of standing water that sits in a basin and is surrounded by land. It is the usual word for inland water that is too big to be called a pond.

Most lakes hold freshwater and are fed by rivers, streams, rain or springs. Lake Superior in North America is a classic example. Not every lake is fresh, though: the Great Salt Lake in the United States is far saltier than the ocean.

The defining feature is that a lake is landlocked. It is not separated from the sea by a coastal barrier because it is not on the coast in that way at all.

What does “lagoon” mean?

A lagoon is a shallow body of water that is partly or fully separated from a larger body of water, usually the sea, by a barrier. That barrier can be a sandbar, a barrier island or a coral reef.

Because lagoons sit next to the sea, their water is typically salty or brackish, meaning a mix of fresh and salt water. Narrow channels often let tides flow in and out. The Venice Lagoon in Italy is a well-known example.

The word also describes the calm water inside a coral atoll, where a ring of reef shelters a pool in the middle. Coastal lagoons and atoll lagoons are different in origin, but both are cut off from open water by a natural barrier.

Lagoon vs Lake: Is a Lagoon a Lake?

Not in the strict sense. A lagoon is tied to the sea, while a lake is tied to the land.

Here are the main points that separate them:

• Location: lagoons are on the coast; lakes are inland.
• Water type: lagoons are usually salty or brackish; lakes are usually fresh.
• Barrier: a lagoon is held back from the sea by a sandbar or reef; a lake needs no such barrier.
• Depth: lagoons are generally shallow, while lakes can be very deep.

Names can be misleading, though, which is why common usage sometimes blurs the line.

Why is Chilika called a lake if it is a lagoon?

Chilika Lake in Odisha, India, is a good example of a name that does not match the geography. It is widely described as a brackish water lagoon separated from the Bay of Bengal by a sandy ridge, yet it is called a lake.

Local and historical naming often wins over scientific classification. When you see “lake” in a name, check where the water comes from and whether it touches the sea before deciding which it really is.

Is the Blue Lagoon a real lagoon?

“Blue Lagoon” is best known as the name of a geothermal spa in Iceland, so it is a place name rather than a plain description. When it is capitalized, it usually points to that attraction.

In lowercase, “blue lagoon” simply describes a clear, bright stretch of lagoon water. Capital letters usually separate the place from the general term.

Lagoon vs Lake: How Can You Remember Which One to Use?

Ask one question: does the water sit behind a barrier next to the sea? If yes, it is a lagoon. If land surrounds it, it is a lake.

You can also use the taste test as a rough guide. Salty or brackish coastal water points to a lagoon, while fresh inland water points to a lake. Use it as a hint, not a rule, because salty lakes and fresh lagoons both exist.

What are common mistakes with lagoon vs lake?

• ✗ A lagoon is just a small lake.
  ✓ A lagoon is a coastal water body behind a barrier, while a lake is surrounded by land.
• ✗ All lakes are freshwater.
  ✓ Most are, but some, like the Great Salt Lake, are salty.
• ✗ Lagoons only exist in the tropics.
  ✓ Lagoons form on coasts worldwide, including Venice in Italy.
• ✗ If the name says lake, it must be a lake.
  ✓ Chilika Lake is described as a lagoon despite its name.
• ✗ Every lagoon is part of a coral reef.
  ✓ Many lagoons form behind sandbars and barrier islands, with no coral at all.

What are some memory tricks?

• Land vs sea: Lake = Land all around. Lagoon = a barrier between it and the sea.
• The barrier test: if you can point to a sandbar, island or reef shielding the water, call it a lagoon.
• The coast check: far from the coast, think lake; right beside the sea, think lagoon.

Frequently asked questions

Is a lagoon a type of lake?

Not exactly. A lagoon is a shallow body of water next to the sea, separated by a barrier, while a lake is surrounded by land. Some lagoons are called lakes by name.

Is lagoon water saltwater or freshwater?

Usually salty or brackish, because it connects to or draws from the sea. Some coastal lagoons can be fresh.

Are all lakes freshwater?

No. Most are, but some, such as the Great Salt Lake in the United States, are saline.

What is a lagoon in an atoll?

It is the calm, shallow water enclosed by a ring of coral reef.

Can people swim in lagoons and lakes?

Often, yes, but check local water quality, wildlife and safety notices first.

Conclusion

The difference in lagoon vs lake comes down to the sea: a lagoon sits behind a barrier beside it, and a lake is surrounded by land. Remember the barrier test and you will rarely get it wrong. Share this with someone who mixes these up, then retake the quiz above to see what stuck.