Hearing is also tough for otters, in the noisy underwater environment.

由于水下环境非常嘈杂，海獭的听觉也会受限。

This lake had laid frozen for many thousands of years, effectively cocooning its underwater environment from the outside world.

这个湖已经冻结了数千年，有效地将其水下环境与外界隔绝开来。