brackish water area; estuarine waters
Technical term used in geography, ecology, and environmental science to refer to the zone where fresh water and seawater mix, such as an estuary.
A unique ecosystem forms in brackish water areas.
海水 means 'seawater', while 汽水域 refers to the transitional zone where seawater and freshwater mix.
Compound of 汽水, “brackish water,” and 域, “area” or “zone.”