Random Thought # 104

I wonder why there is so much salt on this earth. If you think about the Dead Sea, Great Salt Lake, Salt Flats in Utah, Salt Mines in east Africa and all of the oceans throughout the world, there is a lot of salt. I'm especially curious why the bulk of our water is salty. Water is fundamental to sustaining life. Why is the biggest source of it salty? Was the salt meant as a deterrent so that we don't waste it? Is there some use for it? How does marine life filter it out and what do they do with it? Just another random thought