The second, third and forth trumpets
Rev 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;
This may be a comet or meteor from outer space. It was burning and turned a third part of the sea as it were blood. One object fell in a sea. There are seven seas and four oceans. This must refer to the sea near Israel. Was this the lake called the Sea of Galilee? No, the Mediterranean Sea is a larger sea in this region near Jerusalem and the Mideast nations.
Rev 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.
A third part of the sea and a third part of the ships, perhaps with their crews, were destroyed.
Rev 8:10 And the third angel sounded, and there fell a great star from heaven, burning as it were a lamp, and it fell upon the third part of the rivers, and upon the fountains of waters;
Another object looking like a burning star, falls from heaven. This time it falls upon a third of the streams and the springs of water.
Rev 8:11 And the name of the star is called Wormwood: and the third part of the waters became wormwood; and many men died of the waters, because they were made bitter.
The waters were made bitter causing many to die. Wormwood is a bitter weed. This was a bitterness of the natural waters. To be sure many were perplexed and were bitter of spirit.
Exo 15:23 And when they came to Marah, they could not drink of the waters of Marah, for they were bitter: therefore the name of it was called Marah.
Exo 15:24 And the people murmured against Moses, saying, What shall we drink?
Exo 15:25 And he cried unto the LORD; and the LORD showed him a tree, which when he had cast into the waters, the waters were made sweet: there he made for them a statute and an ordinance, and there he proved them,
Jesus on the tree, removes the bitterness of life.
Heb 12:15 Looking diligently lest any man fail of the grace of God; lest any root of bitterness springing up trouble you, and thereby many be defiled;
These people were already defiled by following the antichrist. They were receiving judgment for their wrong choices and the creation suffered because of them.
Rom 8:22 For we know that the whole creation groaneth and travaileth in pain together until now.
Rom 8:23 And not only they, but ourselves also, which have the firstfruits of the Spirit, even we ourselves groan within ourselves, waiting for the adoption, to wit, the redemption of our body.
Rev 8:12 And the fourth angel sounded, and the third part of the sun was smitten, and the third part of the moon, and the third part of the stars; so as the third part of them was darkened, and the day shone not for a third part of it, and the night likewise.
Mat 24:29 Immediately after the tribulation of those days shall the sun be darkened, and the moon shall not give her light, and the stars shall fall from heaven, and the powers of the heavens shall be shaken:
A third of the day will be in complete darkness, no sun and a third of the night, with no light from the moon or stars. God is in control of His creation. He covered this region with a blanket of darkness. These things must occur before Jesus returns.
Mat 24:30 And then shall appear the sign of the Son of man in heaven: and then shall all the tribes of the earth mourn, and they shall see the Son of man coming in the clouds of heaven with power and great glory.
Revelation is a look into the future. The Chapters are not necessarily in order of things happening, rather they are a record of what was revealed to John by Jesus. These things will occur as God sends them according to His time. People tend to trust in their natural things; God will remove them. Those who trust in themselves and government see that these things are crumbling. God is to be honored and trusted above all else.