Hmm... so the reference to water turning to blood is from the Bible? Revelations and sorta end times signs? So hard to reference the Bible these days. Every site has a heavy religious overtone and I want to avoid all that and speculate purely from a prophetic view point. To simply read the scripture and try to compare it to modern day events if at all possible without waxing into churchdom or religulessness.
I think the reference comes from chapter 8: verse 8-9.
King James Version (KJV)
8 And the second angel sounded, and as it were a great mountain burning with fire was cast into the sea: and the third part of the sea became blood;
9 And the third part of the creatures which were in the sea, and had life, died; and the third part of the ships were destroyed.
The thing about this particular vision is that it was defined and interpreted 2000 years ago by someone who had little knowledge of modern technology, but received instruction about what to write on the events so that we here and now could maybe get what was being revealed.
My take on those two verses is the Gulf oil spill. It fits like I know no other single event could. Even the destruction of ships can be interpreted to mean the failing fishing businesses that depended on the seafood polluted by the oil. Hard to quantify by "thirds" because the media downplays the true extent of the damage. And maybe the interpretation of the vision by John of Patmos was muddled in his own mind when he wrote it down. Who knows? Just my take on this one.