Revelation 16:3
The second angel poured out his bowl on the sea, and it became blood like that of a dead man, and every living thing in the sea died.
Revelation 8:8-9
The second angel sounded his trumpet, and something like a great mountain burning with fire was thrown into the sea; and a third of the sea became blood,
Revelation 11:6
These have the power to shut up the sky, so that rain will not fall during the days of their prophesying; and they have power over the waters to turn them into blood, and to strike the earth with every plague, as often as they desire.
Revelation 10:2
He had a little scroll which was open in his hand. And he set his right foot on the sea, and his left foot on the land,
Revelation 13:1
And the dragon stood on the shore of the sea. And I saw a beast coming out of the sea. He had ten horns and seven heads, with ten diadems on his horns, and on his heads were blasphemous names.