“sea change” is a phrase evocative of something it no longer means
Shakespeare (great coiner of phrases and words) first used “sea change” in The Tempest:
Full fathom five thy father lies:
Of his bones are coral made:
Those are pearls that were his eyes:
Nothing of him that doth fade
But doth suffer a sea-change
Into something rich and strange.
“Sea change” has come to mean large and sudden shifts/changes, rather than “rich and strange” ones.
Even though it’s not explicit (even in the Shakespeare), the phrase always evokes, for me, images of bodies broken and beaten by water, made unhuman by constant exposure to nature. Despite the grotesque images that sometimes come to mind, the phrase still sounds pleasant to me, and according the Shakespeare in some ways is.
It’s also an album by Beck with artwork by Jeremy Blake, who also did some abstract and colorful scenes in Punch Drunk Love.