Revelation 16:3
The second emptied his bowl upon the sea, and it turned into blood like a dead man's, and every live thing in the sea died.
Revelation 8:8-9
Then the second angel blew his trumpet, and what looked like a great mountain ablaze with fire was thrown into the sea, and one third of the sea turned into blood,
Revelation 11:6
They have the power to shut up the sky, so that no rain will fall during the days when they are prophesying, and they have power to turn the waters into blood and to smite the earth with any plague whenever they please.
Revelation 10:2
and he had a little scroll open in his hand. He set his right foot on the sea and his left foot on the land,
Revelation 13:1
Then I stood on the sand of the seashore, and I saw an animal come up out of the sea with ten horns and seven heads, and with ten diadems on its horns, and blasphemous titles on its heads.