Revelation 16:3
The second angel poured his bowl into the sea, and it became blood, like a dead man's blood, and every living creature in the sea died.
Revelation 8:8-9
The second angel blew his trumpet; and what seemed to be a great mountain, all ablaze with fire, was hurled into the sea; and a third part of the sea was turned into blood.
Revelation 11:6
They have power given to them to seal up the sky, so that no rain may fall so long as they continue to prophesy; and power over the waters to turn them into blood, and to smite the earth with various plagues whenever they choose to do so.
Revelation 10:2
In his hand he held a small scroll unrolled; and, planting his right foot on the sea and his left foot on the land,
Revelation 13:1
And he took up a position upon the sands of the sea-shore. Then I saw a Wild Beast coming up out of the sea, and he had ten horns and seven heads. On his horns were ten kingly crowns, and inscribed on his heads were names full of blasphemy.