Second Trumpet - Third part of Sea became blood
Trumpet - God's Judgement on the Roman Empire (First Beast)
Revelation 8:8 - 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;
Revelation 8:9 - 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.
Daniel 2:35 - Then was the iron, the clay, the brass, the silver, and the gold, broken to pieces together, and became like the chaff of the summer threshingfloors; and the wind carried them away, that no place was found for them: and the stone that smote the image became a great mountain, and filled the whole earth.
Daniel 2:44 - And in the days of these kings shall the God of heaven set up a kingdom, which shall never be destroyed: and the kingdom shall not be left to other people, but it shall break in pieces and consume all these kingdoms, and it shall stand for ever.
Jeremiah 51:24-25 - And I will render unto Babylon and to all the inhabitants of Chaldea all their evil that they have done in Zion in your sight, saith the LORD. Behold, I am against you, O destroying mountain, Who destroys all the earth, says the Lord. And I will stretch out My hand against you, Roll you down from the rocks, And make you a burnt mountain.
Revelation 17:15 - Then he said to me, The waters which you saw, where the harlot sits, are peoples, multitudes, nations, and tongues.
Jeremiah 51:36 - Therefore thus says the Lord: Behold, I will plead your case and take vengeance for you. I will dry up her (Babylon) sea and make her springs dry.
Isaiah 8:7 - Now therefore, behold, the Lord brings up over them The waters of the River, strong and mighty-- The king of Assyria and all his glory; He will go up over all his channels And go over all his banks.
Isaiah 8:8 - He will pass through Judah, He will overflow and pass over, He will reach up to the neck; And the stretching out of his wings Will fill the breadth of Your land, O Immanuel.
Isaiah 17:12 - Woe to the multitude of many people Who make a noise like the roar of the seas, And to the rushing of nations That make a rushing like the rushing of mighty waters!
Isaiah 17:13 - The nations will rush like the rushing of many waters; But God will rebuke them and they will flee far away, And be chased like the chaff of the mountains before the wind, Like a rolling thing before the whirlwind.
Psalms 65:7 - You who still the noise of the seas, The noise of their waves, And the tumult of the peoples.
In 425 A.D, Genseric (Tyrant of the sea) waged naval warfare, destroyed Roman naval ships, sea were turned into blood as the sailors were killed.
The Sack of Rome in 455 A.D was the second of three ancient sacks of Rome; It was conducted by the Vandals king Genseric, who was then at war with the Western Roman Emperor Petronius Maximus.
Upon the Vandal arrival, according to the chronicler Prosper of Aquitaine, Pope Leo I requested that Genseric not destroy the ancient city nor murder its inhabitants. Genseric agreed and the gates of Rome were thrown open to him and his men.
It is accepted that Genseric looted great amounts of treasure from the city, damaging the Temple of Jupiter Optimus Maximus by stripping away the gilt bronze roof tiles. Hence the modern term Vandalism. The sack of 455 A.D is generally seen as being more thorough than the Visigothic Sack of 410 A.D, because the Vandals plundered Rome for fourteen days whereas the Visigoths spent only three days in the city.
Modern historians like John Henry Haaren stated that there were temples, public buildings, private houses and even the emperor's palace that were sacked. Besides taking many Romans as slaves, the Vandals also committed other depredation like taking immense quantities of gold, silver, jewels and furniture, destroyed works of art, and killed a number of citizens.
Genseric, who was known as the tyrant of the seas fought naval battles against Rome in the Mediterranean Sea between 425 A.D – 470 A.D., and they destroyed Roman ships by pirating the seas (1/3rd the seas). Genseric sent a fleet of 500 Vandal ships against the Romans, losing 340 ships in the first engagement, but succeeded in destroying 600 Roman ships in the second literally fulfilling the destruction of ships mentioned in Revelation 8:9. The Romans abandoned the campaign and Genseric remained master of the western Mediterranean until his death, ruling from the Strait of Gibraltar all the way to Tripolitania.
Thus the second trumpet ushered in ruin on the Roman world by a heavier plague.