Into the sea (εις την θαλασσαν). Like the first Egyptian plague (Exodus 7:12-41) though only the Nile affected then.

Blood as of a dead man (αιμα ως νεκρου). At the trumpet (Revelation 8:11) the water becomes wormwood. Here ως νεκρου is added to Exodus 7:19, "the picture of a murdered man weltering in his blood" (Swete). "Coagulated blood, fatal to animal life" (Moffatt).

Every living soul (πασα ψυχη ζωης). "Every soul of life" (Hebraism, Genesis 1:21, marked by life).

Even the things that were in the sea (τα εν τη θαλασση). "The things in the sea," in apposition with ψυχη. Complete destruction, not partial as in Revelation 8:9.