Revelation 16:3
And the second poured out his bowl into the sea; and it became blood, as of a dead man; and every living soul died, the things in the sea.
Revelation 8:8-9
And the second angel sounded, and as it were a great mountain burning with fire was cast into the sea; and the third part of the sea became blood;
Revelation 11:6
These have authority to shut the heaven, that it rain not in the days of their prophecy; and they have authority over the waters, to turn them into blood, and to smite the earth with every plague, as often as they may wish.
Revelation 10:2
And he had in his hand a little book opened; and he set his right foot on the sea, and his left on the land;
Revelation 13:1
(12:18) and he stood upon the sand of the sea. (13:1) And I saw a beast coming up out of the sea, having ten horns and seven heads, and on his horns ten diadems, and upon his heads names of blasphemy.