Revelation 16:3-6

³ The second [angel] emptied his bowl into the sea, and it turned into blood like that of a corpse [thick, corrupt, ill-smelling, and disgusting], and every living thing that was in the sea perished.

•  A Sea is a smaller body of water then an ocean. So the small group who take the mark are doomed, Revelation 14:8-9. Once again I believe this to be the fallen angels.
• There is no forgiveness for this sin. It is blasphemy of the Holy Spirit, Matthew 12:31. 
• We talked about this yesterday, but let's go over it again.
• The Bible never spells out specifically what taking the mark is or what blasphemy of Holy Spirit is. But we are told that the fallen angels will not be forgiven, 2 Peter 2:4.
• We are told that the fallen angels have been cast to the earth, Revelation 12:9.
• We are told that we are to beware that we may be in contact with angels, Hebrews 13:2.
• This is what I believe: man cannot commit this sin. I believe that this is a sin of the fallen angels who have been cast out of Heaven and who dwell among us.
• John 17:2 and Romans 5 tell us that Jesus controls all mankind and that His sacrifice saved all mankind. We are told that where sin abounds, grace much more abounds. We are told that Jesus’ sacrifice far outweighs man's sin. 
• Also if this sin is unforgiveable and we can commit it, why did our Father not tell us, who are to come to Him as little children, exactly what it is? If there is a sin that we cannot come back from then how can there be any grey area. We are little kids, we need to be specifically told.

⁴ Then the third [angel] emptied out his bowl into the rivers and the springs of water, and they turned into (became) blood.

• Rivers and streams are the things that feed the sea. So the infrastructure of the anti-christ’s kingdom is doomed to fail. 
• The beast and his kingdom are built on sand, not on rock, Revelation 13:1.

⁵ And I also heard the angel of the waters say, Righteous (just) are You in these Your decisions and judgments, You Who are and were, O Holy One!

⁶ Because they have poured out the blood of Your people (the saints) and the prophets, and You have given them blood to drink. Such is their due [they deserve it]!

• The beast, dragon, and fallen angels come after the woman, the Church, Revelation 12:15.