Lagoon

A lake, also called a lagoon or lagoon, is a landform in which part of an inland bay or shallow sea is separated from the open sea by a sand spit, sandbar, or coastal bar. The water is generally shallow. Seawater and land water mix together to form brackish water, but the water often flows with the open seawater through a tidal inlet as the tides rise and fall, and the salinity changes greatly over time and space. They often develop on coasts where the seabed has a relatively gentle slope and small tidal range, and for this reason, in Japan they are more common along the coasts of the Sea of ​​Japan and the Sea of ​​Okhotsk than on the Pacific coast. They are often gradually filled in to become coastal marshes, or are artificially drained and filled in. Lake Saroma in Hokkaido, Kahokugata in Ishikawa Prefecture, and Hachirogata in Akita Prefecture, which has been reclaimed by land reclamation, are typical examples of lagoons.

[Kazunori Mori]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

内湾や浅海の一部が、砂嘴(さし)や砂州、または沿岸州によって外海から切り離され、湖となった地形で、潟湖(せきこ)・ラグーンともいう。一般に水深は浅い。海水と陸水が混じり合い汽水をたたえるが、潮口を通して、干満に伴う外海水との交流が行われることが多く、塩分は時間的にも空間的にも大きく変化する。海底が比較的緩傾斜で潮差が小さい沿岸によく発達し、このため日本では太平洋側より日本海とオホーツク海沿岸に多くみられる。しだいに埋め立てられて海岸湿地となる場合や、人工的に排水されて埋め立てられることが多い。北海道のサロマ湖、石川県の河北潟(かほくがた)、干拓が進められた秋田県の八郎潟などは潟の典型的な例である。

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