noun
blue tide; upwelling of oxygen-depleted water
An oceanographic phenomenon where cold, oxygen-poor water rises to the surface, often causing fish kills and a bluish discoloration. The term is used in environmental and fisheries contexts.
東京湾で青潮が発生し、多くの魚が死んだ。
A blue tide occurred in Tokyo Bay, killing many fish.
青潮の原因は、貧酸素水塊の湧昇だと考えられている。
The cause of the blue tide is thought to be the upwelling of hypoxic water masses.