Origin of the Ocean

It is likely that millions of years of earthquake and volcanic activity release molten rocks and also clouds of carbon dioxide, nitrogen, and water vapor. The first water vapor that hissed out of the boiling surface of the earth joined with other gases to form a thick atmosphere, which wrapped a dark pall around the planet earth.

When temperatures above the earth became cool enough to allow the vapor to condense into rain, it fell toward the earth but was quickly boiled back into the gaseous state as it approached the scorching earth.

Ever so slowly the earth cooled. When the rocks were cooler than the boiling point of water, some rain fell to the surface and stayed there. The water from the clouds no longer immediately vaporized when it fell to the earth. Hence the ocean was formed. Some of the ocean water on earth may have come from the impact of comets.

The ocean level at the beginning were much lower than the ocean level they are today. The ocean level in recent years seem to have been determined mainly by the amount of water trapped in glaciers and by the slow rise of land masses as the cruts of hte earth adjusts itself to stresses. Of course, ocean life that existed then are very different from ocean life that exist today.