A Celebration at Sea

What could this be when most landlubbers are abed?
Neptune has whipped up his charges into a vigorous
Spring clean. His sandy shores must be swept clean
of Autumn's fallen weeds. A wind from the East is better
than a thousand brushes. This is all in preparation
for a new birth of marine life? What we can see cast in
the air will, below the waves, be a swirl of the confetti
of celebration that the fruit trees of the sea have been
pruned.